Azure Functions C# script (.csx) developer reference

Article
09/27/2023

This article is an introduction to developing Azure Functions by using C# script (.csx).

Important

C# script is supported primarily to provide a convenient in-portal experience to help you quickly get started creating and running C# functions. For production-quality apps, you should instead develop your C# functions locally as a compiled C# class library project. To learn how to migrate a C# script project to a C# class library (isolated worker) project, see Convert a C# script app to a C# project.

Azure Functions lets you develop functions using C# in one of the following ways:

Type	Execution process	Code extension	Development environment	Reference
C# script	in-process	.csx	Portal Core Tools	This article
C# class library (isolated worker)	isolated worker process	.cs	Visual Studio Visual Studio Code Core Tools	.NET isolated worker process functions
C# class library (in-process)	in-process	.cs	Visual Studio Visual Studio Code Core Tools	In-process C# class library functions

How .csx works

Data flows into your C# function via method arguments. Argument names are specified in a function.json file, and there are predefined names for accessing things like the function logger and cancellation tokens.

The .csx format allows you to write less "boilerplate" and focus on writing just a C# function. Instead of wrapping everything in a namespace and class, just define a Run method. Include any assembly references and namespaces at the beginning of the file as usual.

A function app's .csx files are compiled when an instance is initialized. This compilation step means things like cold start may take longer for C# script functions compared to C# class libraries. This compilation step is also why C# script functions are editable in the Azure portal, while C# class libraries aren't.

Folder structure

The folder structure for a C# script project looks like the following example:

FunctionsProject
 | - MyFirstFunction
 | | - run.csx
 | | - function.json
 | | - function.proj
 | - MySecondFunction
 | | - run.csx
 | | - function.json
 | | - function.proj
 | - host.json
 | - extensions.csproj
 | - bin

There's a shared host.json file that can be used to configure the function app. Each function has its own code file (.csx) and binding configuration file (function.json).

The binding extensions required in version 2.x and later versions of the Functions runtime are defined in the extensions.csproj file, with the actual library files in the bin folder. When developing locally, you must register binding extensions. When you develop functions in the Azure portal, this registration is done for you.

Binding to arguments

Input or output data is bound to a C# script function parameter via the name property in the function.json configuration file. The following example shows a function.json file and run.csx file for a queue-triggered function. The parameter that receives data from the queue message is named myQueueItem because that's the value of the name property.

{
    "disabled": false,
    "bindings": [
        {
            "type": "queueTrigger",
            "direction": "in",
            "name": "myQueueItem",
            "queueName": "myqueue-items",
            "connection":"MyStorageConnectionAppSetting"
        }
    ]
}

#r "Microsoft.WindowsAzure.Storage"

using Microsoft.Extensions.Logging;
using Microsoft.WindowsAzure.Storage.Queue;
using System;

public static void Run(CloudQueueMessage myQueueItem, ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem.AsString}");
}

The #r statement is explained later in this article.

Supported types for bindings

Each binding has its own supported types; for instance, a blob trigger can be used with a string parameter, a POCO parameter, a CloudBlockBlob parameter, or any of several other supported types. The binding reference article for blob bindings lists all supported parameter types for blob triggers. For more information, see Triggers and bindings and the binding reference docs for each binding type.

Tip

If you plan to use the HTTP or WebHook bindings, plan to avoid port exhaustion that can be caused by improper instantiation of HttpClient. For more information, see How to manage connections in Azure Functions.

Referencing custom classes

If you need to use a custom Plain Old CLR Object (POCO) class, you can include the class definition inside the same file or put it in a separate file.

The following example shows a run.csx example that includes a POCO class definition.

public static void Run(string myBlob, out MyClass myQueueItem)
{
    log.Verbose($"C# Blob trigger function processed: {myBlob}");
    myQueueItem = new MyClass() { Id = "myid" };
}

public class MyClass
{
    public string Id { get; set; }
}

A POCO class must have a getter and setter defined for each property.

Reusing .csx code

You can use classes and methods defined in other .csx files in your run.csx file. To do that, use #load directives in your run.csx file. In the following example, a logging routine named MyLogger is shared in myLogger.csx and loaded into run.csx using the #load directive:

Example run.csx:

#load "mylogger.csx"

using Microsoft.Extensions.Logging;

public static void Run(TimerInfo myTimer, ILogger log)
{
    log.LogInformation($"Log by run.csx: {DateTime.Now}");
    MyLogger(log, $"Log by MyLogger: {DateTime.Now}");
}

Example mylogger.csx:

public static void MyLogger(ILogger log, string logtext)
{
    log.LogInformation(logtext);
}

Using a shared .csx file is a common pattern when you want to strongly type the data passed between functions by using a POCO object. In the following simplified example, an HTTP trigger and queue trigger share a POCO object named Order to strongly type the order data:

Example run.csx for HTTP trigger:

#load "..\shared\order.csx"

using System.Net;
using Microsoft.Extensions.Logging;

public static async Task<HttpResponseMessage> Run(Order req, IAsyncCollector<Order> outputQueueItem, ILogger log)
{
    log.LogInformation("C# HTTP trigger function received an order.");
    log.LogInformation(req.ToString());
    log.LogInformation("Submitting to processing queue.");

    if (req.orderId == null)
    {
        return new HttpResponseMessage(HttpStatusCode.BadRequest);
    }
    else
    {
        await outputQueueItem.AddAsync(req);
        return new HttpResponseMessage(HttpStatusCode.OK);
    }
}

Example run.csx for queue trigger:

#load "..\shared\order.csx"

using System;
using Microsoft.Extensions.Logging;

public static void Run(Order myQueueItem, out Order outputQueueItem, ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed order...");
    log.LogInformation(myQueueItem.ToString());

    outputQueueItem = myQueueItem;
}

Example order.csx:

public class Order
{
    public string orderId {get; set; }
    public string custName {get; set;}
    public string custAddress {get; set;}
    public string custEmail {get; set;}
    public string cartId {get; set; }

    public override String ToString()
    {
        return "\n{\n\torderId : " + orderId +
                  "\n\tcustName : " + custName +
                  "\n\tcustAddress : " + custAddress +
                  "\n\tcustEmail : " + custEmail +
                  "\n\tcartId : " + cartId + "\n}";
    }
}

You can use a relative path with the #load directive:

#load "mylogger.csx" loads a file located in the function folder.
#load "loadedfiles\mylogger.csx" loads a file located in a folder in the function folder.
#load "..\shared\mylogger.csx" loads a file located in a folder at the same level as the function folder, that is, directly under wwwroot.

The #load directive works only with .csx files, not with .cs files.

Binding to method return value

You can use a method return value for an output binding, by using the name $return in function.json.

{
    "name": "$return",
    "type": "blob",
    "direction": "out",
    "path": "output-container/{id}"
}

Here's the C# script code using the return value, followed by an async example:

public static string Run(WorkItem input, ILogger log)
{
    string json = string.Format("{{ \"id\": \"{0}\" }}", input.Id);
    log.LogInformation($"C# script processed queue message. Item={json}");
    return json;
}

public static Task<string> Run(WorkItem input, ILogger log)
{
    string json = string.Format("{{ \"id\": \"{0}\" }}", input.Id);
    log.LogInformation($"C# script processed queue message. Item={json}");
    return Task.FromResult(json);
}

Use the return value only if a successful function execution always results in a return value to pass to the output binding. Otherwise, use ICollector or IAsyncCollector, as shown in the following section.

Writing multiple output values

To write multiple values to an output binding, or if a successful function invocation might not result in anything to pass to the output binding, use the ICollector or IAsyncCollector types. These types are write-only collections that are written to the output binding when the method completes.

This example writes multiple queue messages into the same queue using ICollector:

public static void Run(ICollector<string> myQueue, ILogger log)
{
    myQueue.Add("Hello");
    myQueue.Add("World!");
}

Logging

To log output to your streaming logs in C#, include an argument of type ILogger. We recommend that you name it log. Avoid using Console.Write in Azure Functions.

public static void Run(string myBlob, ILogger log)
{
    log.LogInformation($"C# Blob trigger function processed: {myBlob}");
}

Note

For information about a newer logging framework that you can use instead of TraceWriter, see the ILogger documentation in the .NET class library developer guide.

Custom metrics logging

You can use the LogMetric extension method on ILogger to create custom metrics in Application Insights. Here's a sample method call:

logger.LogMetric("TestMetric", 1234);

This code is an alternative to calling TrackMetric by using the Application Insights API for .NET.

Async

To make a function asynchronous, use the async keyword and return a Task object.

public async static Task ProcessQueueMessageAsync(
        string blobName,
        Stream blobInput,
        Stream blobOutput)
{
    await blobInput.CopyToAsync(blobOutput, 4096);
}

You can't use out parameters in async functions. For output bindings, use the function return value or a collector object instead.

Cancellation tokens

A function can accept a CancellationToken parameter, which enables the operating system to notify your code when the function is about to be terminated. You can use this notification to make sure the function doesn't terminate unexpectedly in a way that leaves data in an inconsistent state.

The following example shows how to check for impending function termination.

using System;
using System.IO;
using System.Threading;

public static void Run(
    string inputText,
    TextWriter logger,
    CancellationToken token)
{
    for (int i = 0; i < 100; i++)
    {
        if (token.IsCancellationRequested)
        {
            logger.WriteLine("Function was cancelled at iteration {0}", i);
            break;
        }
        Thread.Sleep(5000);
        logger.WriteLine("Normal processing for queue message={0}", inputText);
    }
}

Importing namespaces

If you need to import namespaces, you can do so as usual, with the using clause.

using System.Net;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

public static Task<HttpResponseMessage> Run(HttpRequestMessage req, ILogger log)

The following namespaces are automatically imported and are therefore optional:

System
System.Collections.Generic
System.IO
System.Linq
System.Net.Http
System.Threading.Tasks
Microsoft.Azure.WebJobs
Microsoft.Azure.WebJobs.Host

Referencing external assemblies

For framework assemblies, add references by using the #r "AssemblyName" directive.

#r "System.Web.Http"

using System.Net;
using System.Net.Http;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

public static Task<HttpResponseMessage> Run(HttpRequestMessage req, ILogger log)

The following assemblies are automatically added by the Azure Functions hosting environment:

mscorlib
System
System.Core
System.Xml
System.Net.Http
Microsoft.Azure.WebJobs
Microsoft.Azure.WebJobs.Host
Microsoft.Azure.WebJobs.Extensions
System.Web.Http
System.Net.Http.Formatting

The following assemblies may be referenced by simple-name, by runtime version:

v2.x+
v1.x

Newtonsoft.Json
Microsoft.WindowsAzure.Storage^*

^*Removed in version 4.x of the runtime.

In code, assemblies are referenced like the following example:

#r "AssemblyName"

Referencing custom assemblies

To reference a custom assembly, you can use either a shared assembly or a private assembly:

Shared assemblies are shared across all functions within a function app. To reference a custom assembly, upload the assembly to a folder named bin in the root folder (wwwroot) of your function app.
Private assemblies are part of a given function's context, and support side-loading of different versions. Private assemblies should be uploaded in a bin folder in the function directory. Reference the assemblies using the file name, such as #r "MyAssembly.dll".

For information on how to upload files to your function folder, see the section on package management.

Watched directories

The directory that contains the function script file is automatically watched for changes to assemblies. To watch for assembly changes in other directories, add them to the watchDirectories list in host.json.

Using NuGet packages

The way that both binding extension packages and other NuGet packages are added to your function app depends on the targeted version of the Functions runtime.

v2.x+
v1.x

By default, the supported set of Functions extension NuGet packages are made available to your C# script function app by using extension bundles. To learn more, see Extension bundles.

If for some reason you can't use extension bundles in your project, you can also use the Azure Functions Core Tools to install extensions based on bindings defined in the function.json files in your app. When using Core Tools to register extensions, make sure to use the --csx option. To learn more, see func extensions install.

By default, Core Tools reads the function.json files and adds the required packages to an extensions.csproj C# class library project file in the root of the function app's file system (wwwroot). Because Core Tools uses dotnet.exe, you can use it to add any NuGet package reference to this extensions file. During installation, Core Tools builds the extensions.csproj to install the required libraries. Here's an example extensions.csproj file that adds a reference to Microsoft.ProjectOxford.Face version 1.1.0:

<Project Sdk="Microsoft.NET.Sdk">
    <PropertyGroup>
        <TargetFramework>netstandard2.0</TargetFramework>
    </PropertyGroup>
    <ItemGroup>
        <PackageReference Include="Microsoft.ProjectOxford.Face" Version="1.1.0" />
    </ItemGroup>
</Project>

Note

For C# script (.csx), you must set TargetFramework to a value of netstandard2.0. Other target frameworks, such as net6.0, aren't supported.

Version 1.x of the Functions runtime uses a project.json file to define dependencies. Here's an example project.json file:

{
  "frameworks": {
    "net46":{
      "dependencies": {
        "Microsoft.ProjectOxford.Face": "1.1.0"
      }
    }
   }
}

Extension bundles aren't supported by version 1.x.

To use a custom NuGet feed, specify the feed in a Nuget.Config file in the function app root folder. For more information, see Configuring NuGet behavior.

If you're working on your project only in the portal, you'll need to manually create the extensions.csproj file or a Nuget.Config file directly in the site. To learn more, see Manually install extensions.

Environment variables

To get an environment variable or an app setting value, use System.Environment.GetEnvironmentVariable, as shown in the following code example:

public static void Run(TimerInfo myTimer, ILogger log)
{
    log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}");
    log.LogInformation(GetEnvironmentVariable("AzureWebJobsStorage"));
    log.LogInformation(GetEnvironmentVariable("WEBSITE_SITE_NAME"));
}

public static string GetEnvironmentVariable(string name)
{
    return name + ": " +
        System.Environment.GetEnvironmentVariable(name, EnvironmentVariableTarget.Process);
}

Retry policies

Functions supports two built-in retry policies. For more information, see Retry policies.

Fixed delay
Exponential backoff

Here's the retry policy in the function.json file:

{
    "disabled": false,
    "bindings": [
        {
            ....
        }
    ],
    "retry": {
        "strategy": "fixedDelay",
        "maxRetryCount": 4,
        "delayInterval": "00:00:10"
    }
}

function.json property	Description
strategy	Use `fixedDelay`.
maxRetryCount	Required. The maximum number of retries allowed per function execution. `-1` means to retry indefinitely.
delayInterval	The delay that's used between retries. Specify it as a string with the format `HH:mm:ss`.

Here's the retry policy in the function.json file:

{
    "disabled": false,
    "bindings": [
        {
            ....
        }
    ],
    "retry": {
        "strategy": "exponentialBackoff",
        "maxRetryCount": 5,
        "minimumInterval": "00:00:10",
        "maximumInterval": "00:15:00"
    }
}

function.json property	Description
strategy	Use `exponentialBackoff`.
maxRetryCount	Required. The maximum number of retries allowed per function execution. `-1` means to retry indefinitely.
minimumInterval	The minimum retry delay. Specify it as a string with the format `HH:mm:ss`.
maximumInterval	The maximum retry delay. Specify it as a string with the format `HH:mm:ss`.

Binding at runtime

In C# and other .NET languages, you can use an imperative binding pattern, as opposed to the declarative bindings in function.json. Imperative binding is useful when binding parameters need to be computed at runtime rather than design time. With this pattern, you can bind to supported input and output bindings on-the-fly in your function code.

Define an imperative binding as follows:

Do not include an entry in function.json for your desired imperative bindings.
Pass in an input parameter Binder binder or IBinder binder.
Use the following C# pattern to perform the data binding.

using (var output = await binder.BindAsync<T>(new BindingTypeAttribute(...)))
{
    ...
}

BindingTypeAttribute is the .NET attribute that defines your binding and T is an input or output type that's supported by that binding type. T can't be an out parameter type (such as out JObject). For example, the Mobile Apps table output binding supports six output types, but you can only use ICollector<T> or IAsyncCollector<T> for T.

Single attribute example

The following example code creates a Storage blob output binding with blob path that's defined at run time, then writes a string to the blob.

using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Host.Bindings.Runtime;

public static async Task Run(string input, Binder binder)
{
    using (var writer = await binder.BindAsync<TextWriter>(new BlobAttribute("samples-output/path")))
    {
        writer.Write("Hello World!!");
    }
}

BlobAttribute defines the Storage blob input or output binding, and TextWriter is a supported output binding type.

Multiple attributes example

The preceding example gets the app setting for the function app's main Storage account connection string (which is AzureWebJobsStorage). You can specify a custom app setting to use for the Storage account by adding the StorageAccountAttribute and passing the attribute array into BindAsync<T>(). Use a Binder parameter, not IBinder. For example:

using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Host.Bindings.Runtime;

public static async Task Run(string input, Binder binder)
{
    var attributes = new Attribute[]
    {
        new BlobAttribute("samples-output/path"),
        new StorageAccountAttribute("MyStorageAccount")
    };

    using (var writer = await binder.BindAsync<TextWriter>(attributes))
    {
        writer.Write("Hello World!");
    }
}

The following table lists the .NET attributes for each binding type and the packages in which they're defined.

Binding	Attribute	Add reference
Azure Cosmos DB	`Microsoft.Azure.WebJobs.DocumentDBAttribute`	`#r "Microsoft.Azure.WebJobs.Extensions.CosmosDB"`
Event Hubs	`Microsoft.Azure.WebJobs.ServiceBus.EventHubAttribute`, `Microsoft.Azure.WebJobs.ServiceBusAccountAttribute`	`#r "Microsoft.Azure.Jobs.ServiceBus"`
Mobile Apps	`Microsoft.Azure.WebJobs.MobileTableAttribute`	`#r "Microsoft.Azure.WebJobs.Extensions.MobileApps"`
Notification Hubs	`Microsoft.Azure.WebJobs.NotificationHubAttribute`	`#r "Microsoft.Azure.WebJobs.Extensions.NotificationHubs"`
Service Bus	`Microsoft.Azure.WebJobs.ServiceBusAttribute`, `Microsoft.Azure.WebJobs.ServiceBusAccountAttribute`	`#r "Microsoft.Azure.WebJobs.ServiceBus"`
Storage queue	`Microsoft.Azure.WebJobs.QueueAttribute`, `Microsoft.Azure.WebJobs.StorageAccountAttribute`
Storage blob	`Microsoft.Azure.WebJobs.BlobAttribute`, `Microsoft.Azure.WebJobs.StorageAccountAttribute`
Storage table	`Microsoft.Azure.WebJobs.TableAttribute`, `Microsoft.Azure.WebJobs.StorageAccountAttribute`
Twilio	`Microsoft.Azure.WebJobs.TwilioSmsAttribute`	`#r "Microsoft.Azure.WebJobs.Extensions.Twilio"`

Convert a C# script app to a C# project

The easiest way to convert a C# script function app to a compiled C# class library project is to start with a new project. You can then, for each function, migrate the code and configuration from each run.csx file and function.json file in a function folder to a single new .cs class library code file. For example, when you have a C# script function named HelloWorld you'll have two files: HelloWorld/run.csx and HelloWorld/function.json. For this function, you create a code file named HelloWorld.cs in your new class library project.

If you are using C# scripting for portal editing, you can download the app content to your local machine. Choose the Site content option instead of Content and Visual Studio project. You don't need to generate a project, and don't include application settings in the download. You're defining a new development environment, and this environment shouldn't have the same permissions as your hosted app environment.

These instructions show you how to convert C# script functions (which run in-process with the Functions host) to C# class library functions that run in an isolated worker process.

Complete the Create a functions app project section from your preferred quickstart:
Create a C# function in Azure from the command line

Create your first C# function in Azure using Visual Studio

Create your first C# function in Azure using Visual Studio Code

If your original C# script code includes an extensions.csproj file or any function.proj files, copy the package references from these file and add them to the new project's .csproj file in the same ItemGroup with the Functions core dependencies.

Tip

Conversion provides a good opportunity to update to the latest versions of your dependencies. Doing so may require additional code changes in a later step.
Copy the contents of the original host.json file into the new project's host.json file, except for the extensionBundles section (compiled C# projects don't use extension bundles and you must explicitly add references to all extensions used by your functions). When merging host.json files, remember that the host.json schema is versioned, with most apps using version 2.0. The contents of the extensions section can differ based on specific versions of the binding extensions used by your functions. See individual extension reference articles to learn how to correctly configure the host.json for your specific versions.
For any shared files referenced by a #load directive, create a new .cs file for each of these shared references. It's simplest to create a new .cs file for each shared class definition. If there are static methods without a class, you need to define new classes for these methods.
Perform the following tasks for each <FUNCTION_NAME> folder in your original project:
1. Create a new file named <FUNCTION_NAME>.cs, replacing <FUNCTION_NAME> with the name of the folder that defined your C# script function. You can create a new function code file from one of the trigger-specific templates in the following way:
  Using the func new --name <FUNCTION_NAME> command and choosing the correct trigger template at the prompt.
  
  Following Add a function to your project in the Visual Studio guide.
  
  Following Add a function to your project in the Visual Studio Code guide.
2. Copy the using statements from your run.csx file and add them to the new file. You do not need any #r directives.
3. For any #load statement in your run.csx file, add a new using statement for the namespace you used for the shared code.
4. In the new file, define a class for your function under the namespace you are using for the project.
5. Create a new method named RunHandler or something similar. This new method serves as the new entry point for the function.
6. Copy the static method that represents your function, along with any functions it calls, from run.csx into your new class as a second method. From the new method you created in the previous step, call into this static method. This indirection step is helpful for navigating any differences as you continue the upgrade. You can keep the original method exactly the same and simply control its inputs from the new context. You may need to create parameters on the new method which you then pass into the static method call. After you have confirmed that the migration has worked as intended, you can remove this extra level of indirection.
7. For each binding in the function.json file, add the corresponding attribute to your new method. To quickly find binding examples, see Manually add bindings based on examples.
8. Add any extension packages required by the bindings to your project, if you haven't already done so.
Recreate any application settings required by your app in the Values collection of the local.settings.json file.
Verify that your project runs locally:
Use func start to run your app from the command line. For more information, see Run functions locally.

Follow the Run functions locally section of the Visual Studio guide.

Follow the Run functions locally section of the Visual Studio Code guide.
Publish your project to a new function app in Azure:
Create your Azure resources and deploy the code project to Azure by using the func azure functionapp publish <APP_NAME> command. For more information, see Deploy project files.

Follow the Publish to Azure section of the Visual Studio guide.

Follow the Create Azure resources section of the Visual Studio Code guide.

Example function conversion

This section shows an example of the migration for a single function.

The original function in C# scripting has two files:

HelloWorld/function.json
HelloWorld/run.csx

The contents of HelloWorld/function.json are:

{
  "bindings": [
    {
      "authLevel": "FUNCTION",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    }
  ]
}

The contents of HelloWorld/run.csx are:

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

public static async Task<IActionResult> Run(HttpRequest req, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    string name = req.Query["name"];

    string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
    dynamic data = JsonConvert.DeserializeObject(requestBody);
    name = name ?? data?.name;

    string responseMessage = string.IsNullOrEmpty(name)
        ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
                : $"Hello, {name}. This HTTP triggered function executed successfully.";

            return new OkObjectResult(responseMessage);
}

After migrating to the isolated worker model with ASP.NET Core integration, these are replaced by a single HelloWorld.cs:

using System.Net;
using Microsoft.Azure.Functions.Worker;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using Microsoft.AspNetCore.Routing;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

namespace MyFunctionApp
{
    public class HelloWorld
    {
        private readonly ILogger _logger;

        public HelloWorld(ILoggerFactory loggerFactory)
        {
            _logger = loggerFactory.CreateLogger<HelloWorld>();
        }

        [Function("HelloWorld")]
        public async Task<IActionResult> RunHandler([HttpTrigger(AuthorizationLevel.Function, "get")] HttpRequest req)
        {
            return await Run(req, _logger);
        }

        // From run.csx
        public static async Task<IActionResult> Run(HttpRequest req, ILogger log)
        {
            log.LogInformation("C# HTTP trigger function processed a request.");

            string name = req.Query["name"];

            string requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            dynamic data = JsonConvert.DeserializeObject(requestBody);
            name = name ?? data?.name;

            string responseMessage = string.IsNullOrEmpty(name)
                ? "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response."
                        : $"Hello, {name}. This HTTP triggered function executed successfully.";

            return new OkObjectResult(responseMessage);
        }
    }
}

Binding configuration and examples

This section contains references and examples for defining triggers and bindings in C# script.

Blob trigger

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `blobTrigger`. This property is set automatically when you create the trigger in the Azure portal.
direction	Must be set to `in`. This property is set automatically when you create the trigger in the Azure portal.
name	The name of the variable that represents the blob in function code.
path	The container to monitor. May be a blob name pattern.
connection	The name of an app setting or setting collection that specifies how to connect to Azure Blobs. See Connections.

The following example shows a blob trigger definition in a function.json file and code that uses the binding. The function writes a log when a blob is added or updated in the samples-workitems container.

Here's the binding data in the function.json file:

{
    "disabled": false,
    "bindings": [
        {
            "name": "myBlob",
            "type": "blobTrigger",
            "direction": "in",
            "path": "samples-workitems/{name}",
            "connection":"MyStorageAccountAppSetting"
        }
    ]
}

The string {name} in the blob trigger path samples-workitems/{name} creates a binding expression that you can use in function code to access the file name of the triggering blob. For more information, see Blob name patterns.

Here's C# script code that binds to a Stream:

public static void Run(Stream myBlob, string name, ILogger log)
{
   log.LogInformation($"C# Blob trigger function Processed blob\n Name:{name} \n Size: {myBlob.Length} Bytes");
}

Here's C# script code that binds to a CloudBlockBlob:

#r "Microsoft.WindowsAzure.Storage"

using Microsoft.WindowsAzure.Storage.Blob;

public static void Run(CloudBlockBlob myBlob, string name, ILogger log)
{
    log.LogInformation($"C# Blob trigger function Processed blob\n Name:{name}\nURI:{myBlob.StorageUri}");
}

Blob input

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `blob`.
direction	Must be set to `in`.
name	The name of the variable that represents the blob in function code.
path	The path to the blob.
connection	The name of an app setting or setting collection that specifies how to connect to Azure Blobs. See Connections.

The following example shows blob input and output bindings in a function.json file and C# script code that uses the bindings. The function makes a copy of a text blob. The function is triggered by a queue message that contains the name of the blob to copy. The new blob is named {originalblobname}-Copy.

In the function.json file, the queueTrigger metadata property is used to specify the blob name in the path properties:

{
  "bindings": [
    {
      "queueName": "myqueue-items",
      "connection": "MyStorageConnectionAppSetting",
      "name": "myQueueItem",
      "type": "queueTrigger",
      "direction": "in"
    },
    {
      "name": "myInputBlob",
      "type": "blob",
      "path": "samples-workitems/{queueTrigger}",
      "connection": "MyStorageConnectionAppSetting",
      "direction": "in"
    },
    {
      "name": "myOutputBlob",
      "type": "blob",
      "path": "samples-workitems/{queueTrigger}-Copy",
      "connection": "MyStorageConnectionAppSetting",
      "direction": "out"
    }
  ],
  "disabled": false
}

Here's the C# script code:

public static void Run(string myQueueItem, string myInputBlob, out string myOutputBlob, ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");
    myOutputBlob = myInputBlob;
}

Blob output

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `blob`.
direction	Must be set to `out`.
name	The name of the variable that represents the blob in function code.
path	The path to the blob.
connection	The name of an app setting or setting collection that specifies how to connect to Azure Blobs. See Connections.

In the function.json file, the queueTrigger metadata property is used to specify the blob name in the path properties:

{
  "bindings": [
    {
      "queueName": "myqueue-items",
      "connection": "MyStorageConnectionAppSetting",
      "name": "myQueueItem",
      "type": "queueTrigger",
      "direction": "in"
    },
    {
      "name": "myInputBlob",
      "type": "blob",
      "path": "samples-workitems/{queueTrigger}",
      "connection": "MyStorageConnectionAppSetting",
      "direction": "in"
    },
    {
      "name": "myOutputBlob",
      "type": "blob",
      "path": "samples-workitems/{queueTrigger}-Copy",
      "connection": "MyStorageConnectionAppSetting",
      "direction": "out"
    }
  ],
  "disabled": false
}

Here's the C# script code:

public static void Run(string myQueueItem, string myInputBlob, out string myOutputBlob, ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");
    myOutputBlob = myInputBlob;
}

RabbitMQ trigger

The following example shows a RabbitMQ trigger binding in a function.json file and a C# script function that uses the binding. The function reads and logs the RabbitMQ message.

Here's the binding data in the function.json file:

{
    "bindings": [
        {
            "name": "myQueueItem",
            "type": "rabbitMQTrigger",
            "direction": "in",
            "queueName": "queue",
            "connectionStringSetting": "rabbitMQConnectionAppSetting"
        }
    ]
}

Here's the C# script code:

using System;

public static void Run(string myQueueItem, ILogger log)
{
    log.LogInformation($"C# Script RabbitMQ trigger function processed: {myQueueItem}");
}

Queue trigger

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `queueTrigger`. This property is set automatically when you create the trigger in the Azure portal.
direction	In the function.json file only. Must be set to `in`. This property is set automatically when you create the trigger in the Azure portal.
name	The name of the variable that contains the queue item payload in the function code.
queueName	The name of the queue to poll.
connection	The name of an app setting or setting collection that specifies how to connect to Azure Queues. See Connections.

The following example shows a queue trigger binding in a function.json file and C# script code that uses the binding. The function polls the myqueue-items queue and writes a log each time a queue item is processed.

Here's the function.json file:

{
    "disabled": false,
    "bindings": [
        {
            "type": "queueTrigger",
            "direction": "in",
            "name": "myQueueItem",
            "queueName": "myqueue-items",
            "connection":"MyStorageConnectionAppSetting"
        }
    ]
}

Here's the C# script code:

#r "Microsoft.WindowsAzure.Storage"

using Microsoft.Extensions.Logging;
using Microsoft.WindowsAzure.Storage.Queue;
using System;

public static void Run(CloudQueueMessage myQueueItem, 
    DateTimeOffset expirationTime, 
    DateTimeOffset insertionTime, 
    DateTimeOffset nextVisibleTime,
    string queueTrigger,
    string id,
    string popReceipt,
    int dequeueCount,
    ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem.AsString}\n" +
        $"queueTrigger={queueTrigger}\n" +
        $"expirationTime={expirationTime}\n" +
        $"insertionTime={insertionTime}\n" +
        $"nextVisibleTime={nextVisibleTime}\n" +
        $"id={id}\n" +
        $"popReceipt={popReceipt}\n" + 
        $"dequeueCount={dequeueCount}");
}

Queue output

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `queue`. This property is set automatically when you create the trigger in the Azure portal.
direction	Must be set to `out`. This property is set automatically when you create the trigger in the Azure portal.
name	The name of the variable that represents the queue in function code. Set to `$return` to reference the function return value.
queueName	The name of the queue.
connection	The name of an app setting or setting collection that specifies how to connect to Azure Queues. See Connections.

The following example shows an HTTP trigger binding in a function.json file and C# script code that uses the binding. The function creates a queue item with a CustomQueueMessage object payload for each HTTP request received.

Here's the function.json file:

{
  "bindings": [
    {
      "type": "httpTrigger",
      "direction": "in",
      "authLevel": "function",
      "name": "input"
    },
    {
      "type": "http",
      "direction": "out",
      "name": "$return"
    },
    {
      "type": "queue",
      "direction": "out",
      "name": "$return",
      "queueName": "outqueue",
      "connection": "MyStorageConnectionAppSetting"
    }
  ]
}

Here's C# script code that creates a single queue message:

public class CustomQueueMessage
{
    public string PersonName { get; set; }
    public string Title { get; set; }
}

public static CustomQueueMessage Run(CustomQueueMessage input, ILogger log)
{
    return input;
}

You can send multiple messages at once by using an ICollector or IAsyncCollector parameter. Here's C# script code that sends multiple messages, one with the HTTP request data and one with hard-coded values:

public static void Run(
    CustomQueueMessage input, 
    ICollector<CustomQueueMessage> myQueueItems, 
    ILogger log)
{
    myQueueItems.Add(input);
    myQueueItems.Add(new CustomQueueMessage { PersonName = "You", Title = "None" });
}

Table input

This section outlines support for the Tables API version of the extension only.

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `table`. This property is set automatically when you create the binding in the Azure portal.
direction	Must be set to `in`. This property is set automatically when you create the binding in the Azure portal.
name	The name of the variable that represents the table or entity in function code.
tableName	The name of the table.
partitionKey	Optional. The partition key of the table entity to read.
rowKey	Optional. The row key of the table entity to read. Can't be used with `take` or `filter`.
take	Optional. The maximum number of entities to return. Can't be used with `rowKey`.
filter	Optional. An OData filter expression for the entities to return from the table. Can't be used with `rowKey`.
connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

The following example shows a table input binding in a function.json file and C# script code that uses the binding. The function uses a queue trigger to read a single table row.

The function.json file specifies a partitionKey and a rowKey. The rowKey value {queueTrigger} indicates that the row key comes from the queue message string.

{
  "bindings": [
    {
      "queueName": "myqueue-items",
      "connection": "MyStorageConnectionAppSetting",
      "name": "myQueueItem",
      "type": "queueTrigger",
      "direction": "in"
    },
    {
      "name": "personEntity",
      "type": "table",
      "tableName": "Person",
      "partitionKey": "Test",
      "rowKey": "{queueTrigger}",
      "connection": "MyStorageConnectionAppSetting",
      "direction": "in"
    }
  ],
  "disabled": false
}

Here's the C# script code:

#r "Azure.Data.Tables"
using Microsoft.Extensions.Logging;
using Azure.Data.Tables;

public static void Run(string myQueueItem, Person personEntity, ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");
    log.LogInformation($"Name in Person entity: {personEntity.Name}");
}

public class Person : ITableEntity
{
    public string Name { get; set; }

    public string PartitionKey { get; set; }
    public string RowKey { get; set; }
    public DateTimeOffset? Timestamp { get; set; }
    public ETag ETag { get; set; }
}

Table output

This section outlines support for the Tables API version of the extension only.

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `table`. This property is set automatically when you create the binding in the Azure portal.
direction	Must be set to `out`. This property is set automatically when you create the binding in the Azure portal.
name	The variable name used in function code that represents the table or entity. Set to `$return` to reference the function return value.
tableName	The name of the table to which to write.
partitionKey	The partition key of the table entity to write.
rowKey	The row key of the table entity to write.
connection	The name of an app setting or setting collection that specifies how to connect to the table service. See Connections.

The following example shows a table output binding in a function.json file and C# script code that uses the binding. The function writes multiple table entities.

Here's the function.json file:

{
  "bindings": [
    {
      "name": "input",
      "type": "manualTrigger",
      "direction": "in"
    },
    {
      "tableName": "Person",
      "connection": "MyStorageConnectionAppSetting",
      "name": "tableBinding",
      "type": "table",
      "direction": "out"
    }
  ],
  "disabled": false
}

Here's the C# script code:

public static void Run(string input, ICollector<Person> tableBinding, ILogger log)
{
    for (int i = 1; i < 10; i++)
        {
            log.LogInformation($"Adding Person entity {i}");
            tableBinding.Add(
                new Person() { 
                    PartitionKey = "Test", 
                    RowKey = i.ToString(), 
                    Name = "Name" + i.ToString() }
                );
        }

}

public class Person
{
    public string PartitionKey { get; set; }
    public string RowKey { get; set; }
    public string Name { get; set; }
}

Timer trigger

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `timerTrigger`. This property is set automatically when you create the trigger in the Azure portal.
direction	Must be set to `in`. This property is set automatically when you create the trigger in the Azure portal.
name	The name of the variable that represents the timer object in function code.
schedule	A CRON expression or a TimeSpan value. A `TimeSpan` can be used only for a function app that runs on an App Service Plan. You can put the schedule expression in an app setting and set this property to the app setting name wrapped in % signs, as in this example: "%ScheduleAppSetting%".
runOnStartup	If `true`, the function is invoked when the runtime starts. For example, the runtime starts when the function app wakes up after going idle due to inactivity. when the function app restarts due to function changes, and when the function app scales out. Use with caution. runOnStartup should rarely if ever be set to `true`, especially in production.
useMonitor	Set to `true` or `false` to indicate whether the schedule should be monitored. Schedule monitoring persists schedule occurrences to aid in ensuring the schedule is maintained correctly even when function app instances restart. If not set explicitly, the default is `true` for schedules that have a recurrence interval greater than or equal to 1 minute. For schedules that trigger more than once per minute, the default is `false`.

The following example shows a timer trigger binding in a function.json file and a C# script function that uses the binding. The function writes a log indicating whether this function invocation is due to a missed schedule occurrence. The TimerInfo object is passed into the function.

Here's the binding data in the function.json file:

{
    "schedule": "0 */5 * * * *",
    "name": "myTimer",
    "type": "timerTrigger",
    "direction": "in"
}

Here's the C# script code:

public static void Run(TimerInfo myTimer, ILogger log)
{
    if (myTimer.IsPastDue)
    {
        log.LogInformation("Timer is running late!");
    }
    log.LogInformation($"C# Timer trigger function executed at: {DateTime.Now}" );  
}

HTTP trigger

The following table explains the trigger configuration properties that you set in the function.json file:

function.json property	Description
type	Required - must be set to `httpTrigger`.
direction	Required - must be set to `in`.
name	Required - the variable name used in function code for the request or request body.
authLevel	Determines what keys, if any, need to be present on the request in order to invoke the function. For supported values, see Authorization level.
methods	An array of the HTTP methods to which the function responds. If not specified, the function responds to all HTTP methods. See customize the HTTP endpoint.
route	Defines the route template, controlling to which request URLs your function responds. The default value if none is provided is `<functionname>`. For more information, see customize the HTTP endpoint.
webHookType	Supported only for the version 1.x runtime. Configures the HTTP trigger to act as a webhook receiver for the specified provider. For supported values, see WebHook type.

The following example shows a trigger binding in a function.json file and a C# script function that uses the binding. The function looks for a name parameter either in the query string or the body of the HTTP request.

Here's the function.json file:

{
    "disabled": false,
    "bindings": [
        {
            "authLevel": "function",
            "name": "req",
            "type": "httpTrigger",
            "direction": "in",
            "methods": [
                "get",
                "post"
            ]
        },
        {
            "name": "$return",
            "type": "http",
            "direction": "out"
        }
    ]
}

Here's C# script code that binds to HttpRequest:

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

public static async Task<IActionResult> Run(HttpRequest req, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    string name = req.Query["name"];
    
    string requestBody = String.Empty;
    using (StreamReader streamReader =  new  StreamReader(req.Body))
    {
        requestBody = await streamReader.ReadToEndAsync();
    }
    dynamic data = JsonConvert.DeserializeObject(requestBody);
    name = name ?? data?.name;
    
    return name != null
        ? (ActionResult)new OkObjectResult($"Hello, {name}")
        : new BadRequestObjectResult("Please pass a name on the query string or in the request body");
}

You can bind to a custom object instead of HttpRequest. This object is created from the body of the request and parsed as JSON. Similarly, a type can be passed to the HTTP response output binding and returned as the response body, along with a 200 status code.

using System.Net;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;

public static string Run(Person person, ILogger log)
{   
    return person.Name != null
        ? (ActionResult)new OkObjectResult($"Hello, {person.Name}")
        : new BadRequestObjectResult("Please pass an instance of Person.");
}

public class Person {
     public string Name {get; set;}
}

HTTP output

The following table explains the binding configuration properties that you set in the function.json file.

Property	Description
type	Must be set to `http`.
direction	Must be set to `out`.
name	The variable name used in function code for the response, or `$return` to use the return value.

Event Hubs trigger

The following table explains the trigger configuration properties that you set in the function.json file:

function.json property	Description
type	Must be set to `eventHubTrigger`. This property is set automatically when you create the trigger in the Azure portal.
direction	Must be set to `in`. This property is set automatically when you create the trigger in the Azure portal.
name	The name of the variable that represents the event item in function code.
eventHubName	Functions 2.x and higher. The name of the event hub. When the event hub name is also present in the connection string, that value overrides this property at runtime. Can be referenced via app settings `%eventHubName%`. In version 1.x, this property is named `path`.
consumerGroup	An optional property that sets the consumer group used to subscribe to events in the hub. If omitted, the `$Default` consumer group is used.
connection	The name of an app setting or setting collection that specifies how to connect to Event Hubs. See Connections.

The following example shows an Event Hubs trigger binding in a function.json file and a C# script function that uses the binding. The function logs the message body of the Event Hubs trigger.

The following examples show Event Hubs binding data in the function.json file for Functions runtime version 2.x and later versions.

{
  "type": "eventHubTrigger",
  "name": "myEventHubMessage",
  "direction": "in",
  "eventHubName": "MyEventHub",
  "connection": "myEventHubReadConnectionAppSetting"
}

Here's the C# script code:

using System;

public static void Run(string myEventHubMessage, TraceWriter log)
{
    log.Info($"C# function triggered to process a message: {myEventHubMessage}");
}

To get access to event metadata in function code, bind to an EventData object. You can also access the same properties by using binding expressions in the method signature. The following example shows both ways to get the same data:

#r "Microsoft.Azure.EventHubs"

using System.Text;
using System;
using Microsoft.ServiceBus.Messaging;
using Microsoft.Azure.EventHubs;

public void Run(EventData myEventHubMessage,
    DateTime enqueuedTimeUtc,
    Int64 sequenceNumber,
    string offset,
    TraceWriter log)
{
    log.Info($"Event: {Encoding.UTF8.GetString(myEventHubMessage.Body)}");
    log.Info($"EnqueuedTimeUtc={myEventHubMessage.SystemProperties.EnqueuedTimeUtc}");
    log.Info($"SequenceNumber={myEventHubMessage.SystemProperties.SequenceNumber}");
    log.Info($"Offset={myEventHubMessage.SystemProperties.Offset}");

    // Metadata accessed by using binding expressions
    log.Info($"EnqueuedTimeUtc={enqueuedTimeUtc}");
    log.Info($"SequenceNumber={sequenceNumber}");
    log.Info($"Offset={offset}");
}

To receive events in a batch, make string or EventData an array:

public static void Run(string[] eventHubMessages, TraceWriter log)
{
    foreach (var message in eventHubMessages)
    {
        log.Info($"C# function triggered to process a message: {message}");
    }
}

Event Hubs output

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
type	Must be set to `eventHub`.
direction	Must be set to `out`. This parameter is set automatically when you create the binding in the Azure portal.
name	The variable name used in function code that represents the event.
eventHubName	Functions 2.x and higher. The name of the event hub. When the event hub name is also present in the connection string, that value overrides this property at runtime. In Functions 1.x, this property is named `path`.
connection	The name of an app setting or setting collection that specifies how to connect to Event Hubs. To learn more, see Connections.

The following example shows an event hub trigger binding in a function.json file and a C# script function that uses the binding. The function writes a message to an event hub.

The following examples show Event Hubs binding data in the function.json file for Functions runtime version 2.x and later versions.

{
    "type": "eventHub",
    "name": "outputEventHubMessage",
    "eventHubName": "myeventhub",
    "connection": "MyEventHubSendAppSetting",
    "direction": "out"
}

Here's C# script code that creates one message:

using System;
using Microsoft.Extensions.Logging;

public static void Run(TimerInfo myTimer, out string outputEventHubMessage, ILogger log)
{
    String msg = $"TimerTriggerCSharp1 executed at: {DateTime.Now}";
    log.LogInformation(msg);   
    outputEventHubMessage = msg;
}

Here's C# script code that creates multiple messages:

public static void Run(TimerInfo myTimer, ICollector<string> outputEventHubMessage, ILogger log)
{
    string message = $"Message created at: {DateTime.Now}";
    log.LogInformation(message);
    outputEventHubMessage.Add("1 " + message);
    outputEventHubMessage.Add("2 " + message);
}

Event Grid trigger

The following table explains the binding configuration properties for C# script that you set in the function.json file. There are no constructor parameters or properties to set in the EventGridTrigger attribute.

function.json property	Description
type	Required - must be set to `eventGridTrigger`.
direction	Required - must be set to `in`.
name	Required - the variable name used in function code for the parameter that receives the event data.

The following example shows an Event Grid trigger defined in the function.json file.

Here's the binding data in the function.json file:

{
  "bindings": [
    {
      "type": "eventGridTrigger",
      "name": "eventGridEvent",
      "direction": "in"
    }
  ],
  "disabled": false
}

Here's an example of a C# script function that uses an EventGridEvent binding parameter:

#r "Azure.Messaging.EventGrid"
using Azure.Messaging.EventGrid;
using Microsoft.Extensions.Logging;

public static void Run(EventGridEvent eventGridEvent, ILogger log)
{
    log.LogInformation(eventGridEvent.Data.ToString());
}

Here's an example of a C# script function that uses a JObject binding parameter:

#r "Newtonsoft.Json"

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

public static void Run(JObject eventGridEvent, TraceWriter log)
{
    log.Info(eventGridEvent.ToString(Formatting.Indented));
}

Event Grid output

The following table explains the binding configuration properties for C# script that you set in the function.json file.

function.json property	Description
type	Must be set to `eventGrid`.
direction	Must be set to `out`. This parameter is set automatically when you create the binding in the Azure portal.
name	The variable name used in function code that represents the event.
topicEndpointUri	The name of an app setting that contains the URI for the custom topic, such as `MyTopicEndpointUri`.
topicKeySetting	The name of an app setting that contains an access key for the custom topic.

The following example shows the Event Grid output binding data in the function.json file.

{
    "type": "eventGrid",
    "name": "outputEvent",
    "topicEndpointUri": "MyEventGridTopicUriSetting",
    "topicKeySetting": "MyEventGridTopicKeySetting",
    "direction": "out"
}

Here's C# script code that creates one event:

#r "Microsoft.Azure.EventGrid"
using System;
using Microsoft.Azure.EventGrid.Models;
using Microsoft.Extensions.Logging;

public static void Run(TimerInfo myTimer, out EventGridEvent outputEvent, ILogger log)
{
    outputEvent = new EventGridEvent("message-id", "subject-name", "event-data", "event-type", DateTime.UtcNow, "1.0");
}

Here's C# script code that creates multiple events:

#r "Microsoft.Azure.EventGrid"
using System;
using Microsoft.Azure.EventGrid.Models;
using Microsoft.Extensions.Logging;

public static void Run(TimerInfo myTimer, ICollector<EventGridEvent> outputEvent, ILogger log)
{
    outputEvent.Add(new EventGridEvent("message-id-1", "subject-name", "event-data", "event-type", DateTime.UtcNow, "1.0"));
    outputEvent.Add(new EventGridEvent("message-id-2", "subject-name", "event-data", "event-type", DateTime.UtcNow, "1.0"));
}

Service Bus trigger

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
type	Must be set to `serviceBusTrigger`. This property is set automatically when you create the trigger in the Azure portal.
direction	Must be set to `in`. This property is set automatically when you create the trigger in the Azure portal.
name	The name of the variable that represents the queue or topic message in function code.
queueName	Name of the queue to monitor. Set only if monitoring a queue, not for a topic.
topicName	Name of the topic to monitor. Set only if monitoring a topic, not for a queue.
subscriptionName	Name of the subscription to monitor. Set only if monitoring a topic, not for a queue.
connection	The name of an app setting or setting collection that specifies how to connect to Service Bus. See Connections.
accessRights	Access rights for the connection string. Available values are `manage` and `listen`. The default is `manage`, which indicates that the `connection` has the Manage permission. If you use a connection string that does not have the Manage permission, set `accessRights` to "listen". Otherwise, the Functions runtime might fail trying to do operations that require manage rights. In Azure Functions version 2.x and higher, this property is not available because the latest version of the Service Bus SDK doesn't support manage operations.
isSessionsEnabled	`true` if connecting to a session-aware queue or subscription. `false` otherwise, which is the default value.
autoComplete	`true` when the trigger should automatically call complete after processing, or if the function code will manually call complete. Setting to `false` is only supported in C#. If set to `true`, the trigger completes the message automatically if the function execution completes successfully, and abandons the message otherwise. <br/When set to `false`, you are responsible for calling ServiceBusReceiver methods to complete, abandon, or deadletter the message, session, or batch. When an exception is thrown (and none of the `ServiceBusReceiver` methods are called), then the lock remains. Once the lock expires, the message is re-queued with the `DeliveryCount` incremented and the lock is automatically renewed. This property is available only in Azure Functions 2.x and higher.

The following example shows a Service Bus trigger binding in a function.json file and a C# script function that uses the binding. The function reads message metadata and logs a Service Bus queue message.

Here's the binding data in the function.json file:

{
"bindings": [
    {
    "queueName": "testqueue",
    "connection": "MyServiceBusConnection",
    "name": "myQueueItem",
    "type": "serviceBusTrigger",
    "direction": "in"
    }
],
"disabled": false
}

Here's the C# script code:

using System;

public static void Run(string myQueueItem,
    Int32 deliveryCount,
    DateTime enqueuedTimeUtc,
    string messageId,
    TraceWriter log)
{
    log.Info($"C# ServiceBus queue trigger function processed message: {myQueueItem}");

    log.Info($"EnqueuedTimeUtc={enqueuedTimeUtc}");
    log.Info($"DeliveryCount={deliveryCount}");
    log.Info($"MessageId={messageId}");
}

Service Bus output

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
type	Must be set to `serviceBus`. This property is set automatically when you create the trigger in the Azure portal.
direction	Must be set to `out`. This property is set automatically when you create the trigger in the Azure portal.
name	The name of the variable that represents the queue or topic message in function code. Set to "$return" to reference the function return value.
queueName	Name of the queue. Set only if sending queue messages, not for a topic.
topicName	Name of the topic. Set only if sending topic messages, not for a queue.
connection	The name of an app setting or setting collection that specifies how to connect to Service Bus. See Connections.
accessRights (v1 only)	Access rights for the connection string. Available values are `manage` and `listen`. The default is `manage`, which indicates that the `connection` has the Manage permission. If you use a connection string that does not have the Manage permission, set `accessRights` to "listen". Otherwise, the Functions runtime might fail trying to do operations that require manage rights. In Azure Functions version 2.x and higher, this property is not available because the latest version of the Service Bus SDK doesn't support manage operations.

The following example shows a Service Bus output binding in a function.json file and a C# script function that uses the binding. The function uses a timer trigger to send a queue message every 15 seconds.

Here's the binding data in the function.json file:

{
    "bindings": [
        {
            "schedule": "0/15 * * * * *",
            "name": "myTimer",
            "runsOnStartup": true,
            "type": "timerTrigger",
            "direction": "in"
        },
        {
            "name": "outputSbQueue",
            "type": "serviceBus",
            "queueName": "testqueue",
            "connection": "MyServiceBusConnection",
            "direction": "out"
        }
    ],
    "disabled": false
}

Here's C# script code that creates a single message:

public static void Run(TimerInfo myTimer, ILogger log, out string outputSbQueue)
{
    string message = $"Service Bus queue message created at: {DateTime.Now}";
    log.LogInformation(message); 
    outputSbQueue = message;
}

Here's C# script code that creates multiple messages:

public static async Task Run(TimerInfo myTimer, ILogger log, IAsyncCollector<string> outputSbQueue)
{
    string message = $"Service Bus queue messages created at: {DateTime.Now}";
    log.LogInformation(message); 
    await outputSbQueue.AddAsync("1 " + message);
    await outputSbQueue.AddAsync("2 " + message);
}

Azure Cosmos DB v2 trigger

This section outlines support for the version 4.x+ of the extension only.

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
type	Must be set to `cosmosDBTrigger`.
direction	Must be set to `in`. This parameter is set automatically when you create the trigger in the Azure portal.
name	The variable name used in function code that represents the list of documents with changes.
connection	The name of an app setting or setting collection that specifies how to connect to the Azure Cosmos DB account being monitored. For more information, see Connections.
databaseName	The name of the Azure Cosmos DB database with the container being monitored.
containerName	The name of the container being monitored.
leaseConnection	(Optional) The name of an app setting or setting container that specifies how to connect to the Azure Cosmos DB account that holds the lease container. When not set, the `connection` value is used. This parameter is automatically set when the binding is created in the portal. The connection string for the leases container must have write permissions.
leaseDatabaseName	(Optional) The name of the database that holds the container used to store leases. When not set, the value of the `databaseName` setting is used.
leaseContainerName	(Optional) The name of the container used to store leases. When not set, the value `leases` is used.
createLeaseContainerIfNotExists	(Optional) When set to `true`, the leases container is automatically created when it doesn't already exist. The default value is `false`. When using Microsoft Entra identities if you set the value to `true`, creating containers is not an allowed operation and your Function won't be able to start.
leasesContainerThroughput	(Optional) Defines the number of Request Units to assign when the leases container is created. This setting is only used when `createLeaseContainerIfNotExists` is set to `true`. This parameter is automatically set when the binding is created using the portal.
leaseContainerPrefix	(Optional) When set, the value is added as a prefix to the leases created in the Lease container for this function. Using a prefix allows two separate Azure Functions to share the same Lease container by using different prefixes.
feedPollDelay	(Optional) The time (in milliseconds) for the delay between polling a partition for new changes on the feed, after all current changes are drained. Default is 5,000 milliseconds, or 5 seconds.
leaseAcquireInterval	(Optional) When set, it defines, in milliseconds, the interval to kick off a task to compute if partitions are distributed evenly among known host instances. Default is 13000 (13 seconds).
leaseExpirationInterval	(Optional) When set, it defines, in milliseconds, the interval for which the lease is taken on a lease representing a partition. If the lease is not renewed within this interval, it will cause it to expire and ownership of the partition will move to another instance. Default is 60000 (60 seconds).
leaseRenewInterval	(Optional) When set, it defines, in milliseconds, the renew interval for all leases for partitions currently held by an instance. Default is 17000 (17 seconds).
maxItemsPerInvocation	(Optional) When set, this property sets the maximum number of items received per Function call. If operations in the monitored container are performed through stored procedures, transaction scope is preserved when reading items from the change feed. As a result, the number of items received could be higher than the specified value so that the items changed by the same transaction are returned as part of one atomic batch.
startFromBeginning	(Optional) This option tells the Trigger to read changes from the beginning of the container's change history instead of starting at the current time. Reading from the beginning only works the first time the trigger starts, as in subsequent runs, the checkpoints are already stored. Setting this option to `true` when there are leases already created has no effect.
startFromTime	(Optional) Gets or sets the date and time from which to initialize the change feed read operation. The recommended format is ISO 8601 with the UTC designator, such as `2021-02-16T14:19:29Z`. This is only used to set the initial trigger state. After the trigger has a lease state, changing this value has no effect.
preferredLocations	(Optional) Defines preferred locations (regions) for geo-replicated database accounts in the Azure Cosmos DB service. Values should be comma-separated. For example, "East US,South Central US,North Europe".

The following example shows an Azure Cosmos DB trigger binding in a function.json file and a C# script function that uses the binding. The function writes log messages when Azure Cosmos DB records are added or modified.

Here's the binding data in the function.json file:

{
    "type": "cosmosDBTrigger",
    "name": "documents",
    "direction": "in",
    "leaseContainerName": "leases",
    "connection": "<connection-app-setting>",
    "databaseName": "Tasks",
    "containerName": "Items",
    "createLeaseContainerIfNotExists": true
}

Here's the C# script code:

    using System;
    using System.Collections.Generic;
    using Microsoft.Extensions.Logging;

    // Customize the model with your own desired properties
    public class ToDoItem
    {
        public string id { get; set; }
        public string Description { get; set; }
    }

    public static void Run(IReadOnlyList<ToDoItem> documents, ILogger log)
    {
      log.LogInformation("Documents modified " + documents.Count);
      log.LogInformation("First document Id " + documents[0].id);
    }

Azure Cosmos DB v2 input

This section outlines support for the version 4.x+ of the extension only.

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
type	Must be set to `cosmosDB`.
direction	Must be set to `in`.
name	The variable name used in function code that represents the list of documents with changes.
connection	The name of an app setting or setting container that specifies how to connect to the Azure Cosmos DB account being monitored. For more information, see Connections.
databaseName	The name of the Azure Cosmos DB database with the container being monitored.
containerName	The name of the container being monitored.
partitionKey	Specifies the partition key value for the lookup. May include binding parameters. It is required for lookups in partitioned containers.
id	The ID of the document to retrieve. This property supports binding expressions. Don't set both the `id` and `sqlQuery` properties. If you don't set either one, the entire container is retrieved.
sqlQuery	An Azure Cosmos DB SQL query used for retrieving multiple documents. The property supports runtime bindings, as in this example: `SELECT * FROM c where c.departmentId = {departmentId}`. Don't set both the `id` and `sqlQuery` properties. If you don't set either one, the entire container is retrieved.
preferredLocations	(Optional) Defines preferred locations (regions) for geo-replicated database accounts in the Azure Cosmos DB service. Values should be comma-separated. For example, `East US,South Central US,North Europe`.

This section contains the following examples:

Queue trigger, look up ID from string
Queue trigger, get multiple docs, using SqlQuery
HTTP trigger, look up ID from query string
HTTP trigger, look up ID from route data
HTTP trigger, get multiple docs, using SqlQuery
HTTP trigger, get multiple docs, using DocumentClient

The HTTP trigger examples refer to a simple ToDoItem type:

namespace CosmosDBSamplesV2
{
    public class ToDoItem
    {
        public string Id { get; set; }
        public string Description { get; set; }
    }
}

Queue trigger, look up ID from string

The following example shows an Azure Cosmos DB input binding in a function.json file and a C# script function that uses the binding. The function reads a single document and updates the document's text value.

Here's the binding data in the function.json file:

{
    "name": "inputDocument",
    "type": "cosmosDB",
    "databaseName": "MyDatabase",
    "collectionName": "MyCollection",
    "id" : "{queueTrigger}",
    "partitionKey": "{partition key value}",
    "connectionStringSetting": "MyAccount_COSMOSDB",
    "direction": "in"
}

Here's the C# script code:

    using System;

    // Change input document contents using Azure Cosmos DB input binding
    public static void Run(string myQueueItem, dynamic inputDocument)
    {
      inputDocument.text = "This has changed.";
    }

Queue trigger, get multiple docs, using SqlQuery

The following example shows an Azure Cosmos DB input binding in a function.json file and a C# script function that uses the binding. The function retrieves multiple documents specified by a SQL query, using a queue trigger to customize the query parameters.

The queue trigger provides a parameter departmentId. A queue message of { "departmentId" : "Finance" } would return all records for the finance department.

Here's the binding data in the function.json file:

{
    "name": "documents",
    "type": "cosmosDB",
    "direction": "in",
    "databaseName": "MyDb",
    "collectionName": "MyCollection",
    "sqlQuery": "SELECT * from c where c.departmentId = {departmentId}",
    "connectionStringSetting": "CosmosDBConnection"
}

Here's the C# script code:

    public static void Run(QueuePayload myQueueItem, IEnumerable<dynamic> documents)
    {
        foreach (var doc in documents)
        {
            // operate on each document
        }
    }

    public class QueuePayload
    {
        public string departmentId { get; set; }
    }

HTTP trigger, look up ID from query string

The following example shows a C# script function that retrieves a single document. The function is triggered by an HTTP request that uses a query string to specify the ID and partition key value to look up. That ID and partition key value are used to retrieve a ToDoItem document from the specified database and collection.

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "cosmosDB",
      "name": "toDoItem",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connectionStringSetting": "CosmosDBConnection",
      "direction": "in",
      "Id": "{Query.id}",
      "PartitionKey" : "{Query.partitionKeyValue}"
    }
  ],
  "disabled": false
}

Here's the C# script code:

using System.Net;
using Microsoft.Extensions.Logging;

public static HttpResponseMessage Run(HttpRequestMessage req, ToDoItem toDoItem, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    if (toDoItem == null)
    {
         log.LogInformation($"ToDo item not found");
    }
    else
    {
        log.LogInformation($"Found ToDo item, Description={toDoItem.Description}");
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

HTTP trigger, look up ID from route data

The following example shows a C# script function that retrieves a single document. The function is triggered by an HTTP request that uses route data to specify the ID and partition key value to look up. That ID and partition key value are used to retrieve a ToDoItem document from the specified database and collection.

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ],
      "route":"todoitems/{partitionKeyValue}/{id}"
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "cosmosDB",
      "name": "toDoItem",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connectionStringSetting": "CosmosDBConnection",
      "direction": "in",
      "id": "{id}",
      "partitionKey": "{partitionKeyValue}"
    }
  ],
  "disabled": false
}

Here's the C# script code:

using System.Net;
using Microsoft.Extensions.Logging;

public static HttpResponseMessage Run(HttpRequestMessage req, ToDoItem toDoItem, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    if (toDoItem == null)
    {
         log.LogInformation($"ToDo item not found");
    }
    else
    {
        log.LogInformation($"Found ToDo item, Description={toDoItem.Description}");
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

HTTP trigger, get multiple docs, using SqlQuery

The following example shows a C# script function that retrieves a list of documents. The function is triggered by an HTTP request. The query is specified in the SqlQuery attribute property.

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "cosmosDB",
      "name": "toDoItems",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connectionStringSetting": "CosmosDBConnection",
      "direction": "in",
      "sqlQuery": "SELECT top 2 * FROM c order by c._ts desc"
    }
  ],
  "disabled": false
}

Here's the C# script code:

using System.Net;
using Microsoft.Extensions.Logging;

public static HttpResponseMessage Run(HttpRequestMessage req, IEnumerable<ToDoItem> toDoItems, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    foreach (ToDoItem toDoItem in toDoItems)
    {
        log.LogInformation(toDoItem.Description);
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

HTTP trigger, get multiple docs, using DocumentClient

The following example shows a C# script function that retrieves a list of documents. The function is triggered by an HTTP request. The code uses a DocumentClient instance provided by the Azure Cosmos DB binding to read a list of documents. The DocumentClient instance could also be used for write operations.

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "cosmosDB",
      "name": "client",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connectionStringSetting": "CosmosDBConnection",
      "direction": "inout"
    }
  ],
  "disabled": false
}

Here's the C# script code:

#r "Microsoft.Azure.Documents.Client"

using System.Net;
using Microsoft.Azure.Documents.Client;
using Microsoft.Azure.Documents.Linq;
using Microsoft.Extensions.Logging;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, DocumentClient client, ILogger log)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    Uri collectionUri = UriFactory.CreateDocumentCollectionUri("ToDoItems", "Items");
    string searchterm = req.GetQueryNameValuePairs()
        .FirstOrDefault(q => string.Compare(q.Key, "searchterm", true) == 0)
        .Value;

    if (searchterm == null)
    {
        return req.CreateResponse(HttpStatusCode.NotFound);
    }

    log.LogInformation($"Searching for word: {searchterm} using Uri: {collectionUri.ToString()}");
    IDocumentQuery<ToDoItem> query = client.CreateDocumentQuery<ToDoItem>(collectionUri)
        .Where(p => p.Description.Contains(searchterm))
        .AsDocumentQuery();

    while (query.HasMoreResults)
    {
        foreach (ToDoItem result in await query.ExecuteNextAsync())
        {
            log.LogInformation(result.Description);
        }
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

Azure Cosmos DB v2 output

This section outlines support for the version 4.x+ of the extension only.

The following table explains the binding configuration properties that you set in the function.json file.

function.json property	Description
connection	The name of an app setting or setting collection that specifies how to connect to the Azure Cosmos DB account being monitored. For more information, see Connections.
databaseName	The name of the Azure Cosmos DB database with the container being monitored.
containerName	The name of the container being monitored.
createIfNotExists	A boolean value to indicate whether the container is created when it doesn't exist. The default is false because new containers are created with reserved throughput, which has cost implications. For more information, see the pricing page.
partitionKey	When `createIfNotExists` is true, it defines the partition key path for the created container. May include binding parameters.
containerThroughput	When `createIfNotExists` is true, it defines the throughput of the created container.
preferredLocations	(Optional) Defines preferred locations (regions) for geo-replicated database accounts in the Azure Cosmos DB service. Values should be comma-separated. For example, `East US,South Central US,North Europe`.

This section contains the following examples:

Queue trigger, write one doc
Queue trigger, write docs using IAsyncCollector

Queue trigger, write one doc

The following example shows an Azure Cosmos DB output binding in a function.json file and a C# script function that uses the binding. The function uses a queue input binding for a queue that receives JSON in the following format:

{
    "name": "John Henry",
    "employeeId": "123456",
    "address": "A town nearby"
}

The function creates Azure Cosmos DB documents in the following format for each record:

{
    "id": "John Henry-123456",
    "name": "John Henry",
    "employeeId": "123456",
    "address": "A town nearby"
}

Here's the binding data in the function.json file:

{
    "name": "employeeDocument",
    "type": "cosmosDB",
    "databaseName": "MyDatabase",
    "collectionName": "MyCollection",
    "createIfNotExists": true,
    "connectionStringSetting": "MyAccount_COSMOSDB",
    "direction": "out"
}

Here's the C# script code:

    #r "Newtonsoft.Json"

    using Microsoft.Azure.WebJobs.Host;
    using Newtonsoft.Json.Linq;
    using Microsoft.Extensions.Logging;

    public static void Run(string myQueueItem, out object employeeDocument, ILogger log)
    {
      log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");

      dynamic employee = JObject.Parse(myQueueItem);

      employeeDocument = new {
        id = employee.name + "-" + employee.employeeId,
        name = employee.name,
        employeeId = employee.employeeId,
        address = employee.address
      };
    }

Queue trigger, write docs using IAsyncCollector

To create multiple documents, you can bind to ICollector<T> or IAsyncCollector<T> where T is one of the supported types.

This example refers to a simple ToDoItem type:

namespace CosmosDBSamplesV2
{
    public class ToDoItem
    {
        public string id { get; set; }
        public string Description { get; set; }
    }
}

Here's the function.json file:

{
  "bindings": [
    {
      "name": "toDoItemsIn",
      "type": "queueTrigger",
      "direction": "in",
      "queueName": "todoqueueforwritemulti",
      "connectionStringSetting": "AzureWebJobsStorage"
    },
    {
      "type": "cosmosDB",
      "name": "toDoItemsOut",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connectionStringSetting": "CosmosDBConnection",
      "direction": "out"
    }
  ],
  "disabled": false
}

Here's the C# script code:

using System;
using Microsoft.Extensions.Logging;

public static async Task Run(ToDoItem[] toDoItemsIn, IAsyncCollector<ToDoItem> toDoItemsOut, ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed {toDoItemsIn?.Length} items");

    foreach (ToDoItem toDoItem in toDoItemsIn)
    {
        log.LogInformation($"Description={toDoItem.Description}");
        await toDoItemsOut.AddAsync(toDoItem);
    }
}

Azure Cosmos DB v1 trigger

Here's the binding data in the function.json file:

{
    "type": "cosmosDBTrigger",
    "name": "documents",
    "direction": "in",
    "leaseCollectionName": "leases",
    "connectionStringSetting": "<connection-app-setting>",
    "databaseName": "Tasks",
    "collectionName": "Items",
    "createLeaseCollectionIfNotExists": true
}

Here's the C# script code:

    #r "Microsoft.Azure.Documents.Client"
    
    using System;
    using Microsoft.Azure.Documents;
    using System.Collections.Generic;
    

    public static void Run(IReadOnlyList<Document> documents, TraceWriter log)
    {
        log.Info("Documents modified " + documents.Count);
        log.Info("First document Id " + documents[0].Id);
    }

Azure Cosmos DB v1 input

This section contains the following examples:

Queue trigger, look up ID from string
Queue trigger, get multiple docs, using SqlQuery
HTTP trigger, look up ID from query string
HTTP trigger, look up ID from route data
HTTP trigger, get multiple docs, using SqlQuery
HTTP trigger, get multiple docs, using DocumentClient

The HTTP trigger examples refer to a simple ToDoItem type:

namespace CosmosDBSamplesV1
{
    public class ToDoItem
    {
        public string Id { get; set; }
        public string Description { get; set; }
    }
}

Queue trigger, look up ID from string

Here's the binding data in the function.json file:

{
    "name": "inputDocument",
    "type": "documentDB",
    "databaseName": "MyDatabase",
    "collectionName": "MyCollection",
    "id" : "{queueTrigger}",
    "partitionKey": "{partition key value}",
    "connection": "MyAccount_COSMOSDB",
    "direction": "in"
}

Here's the C# script code:

    using System;

    // Change input document contents using Azure Cosmos DB input binding
    public static void Run(string myQueueItem, dynamic inputDocument)
    {
        inputDocument.text = "This has changed.";
    }

Queue trigger, get multiple docs, using SqlQuery

The queue trigger provides a parameter departmentId. A queue message of { "departmentId" : "Finance" } would return all records for the finance department.

Here's the binding data in the function.json file:

{
    "name": "documents",
    "type": "documentdb",
    "direction": "in",
    "databaseName": "MyDb",
    "collectionName": "MyCollection",
    "sqlQuery": "SELECT * from c where c.departmentId = {departmentId}",
    "connection": "CosmosDBConnection"
}

Here's the C# script code:

    public static void Run(QueuePayload myQueueItem, IEnumerable<dynamic> documents)
    {
        foreach (var doc in documents)
        {
            // operate on each document
        }
    }

    public class QueuePayload
    {
        public string departmentId { get; set; }
    }

HTTP trigger, look up ID from query string

The following example shows a C# script function that retrieves a single document. The function is triggered by an HTTP request that uses a query string to specify the ID to look up. That ID is used to retrieve a ToDoItem document from the specified database and collection.

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "documentDB",
      "name": "toDoItem",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connection": "CosmosDBConnection",
      "direction": "in",
      "Id": "{Query.id}"
    }
  ],
  "disabled": true
}

Here's the C# script code:

using System.Net;

public static HttpResponseMessage Run(HttpRequestMessage req, ToDoItem toDoItem, TraceWriter log)
{
    log.Info("C# HTTP trigger function processed a request.");

    if (toDoItem == null)
    {
        log.Info($"ToDo item not found");
    }
    else
    {
        log.Info($"Found ToDo item, Description={toDoItem.Description}");
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

HTTP trigger, look up ID from route data

The following example shows a C# script function that retrieves a single document. The function is triggered by an HTTP request that uses route data to specify the ID to look up. That ID is used to retrieve a ToDoItem document from the specified database and collection.

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ],
      "route":"todoitems/{id}"
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "documentDB",
      "name": "toDoItem",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connection": "CosmosDBConnection",
      "direction": "in",
      "Id": "{id}"
    }
  ],
  "disabled": false
}

Here's the C# script code:

using System.Net;

public static HttpResponseMessage Run(HttpRequestMessage req, ToDoItem toDoItem, TraceWriter log)
{
    log.Info("C# HTTP trigger function processed a request.");

    if (toDoItem == null)
    {
        log.Info($"ToDo item not found");
    }
    else
    {
        log.Info($"Found ToDo item, Description={toDoItem.Description}");
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

HTTP trigger, get multiple docs, using SqlQuery

The following example shows a C# script function that retrieves a list of documents. The function is triggered by an HTTP request. The query is specified in the SqlQuery attribute property.

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "documentDB",
      "name": "toDoItems",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connection": "CosmosDBConnection",
      "direction": "in",
      "sqlQuery": "SELECT top 2 * FROM c order by c._ts desc"
    }
  ],
  "disabled": false
}

Here's the C# script code:

using System.Net;

public static HttpResponseMessage Run(HttpRequestMessage req, IEnumerable<ToDoItem> toDoItems, TraceWriter log)
{
    log.Info("C# HTTP trigger function processed a request.");

    foreach (ToDoItem toDoItem in toDoItems)
    {
        log.Info(toDoItem.Description);
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

HTTP trigger, get multiple docs, using DocumentClient

Here's the function.json file:

{
  "bindings": [
    {
      "authLevel": "anonymous",
      "name": "req",
      "type": "httpTrigger",
      "direction": "in",
      "methods": [
        "get",
        "post"
      ]
    },
    {
      "name": "$return",
      "type": "http",
      "direction": "out"
    },
    {
      "type": "documentDB",
      "name": "client",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connection": "CosmosDBConnection",
      "direction": "inout"
    }
  ],
  "disabled": false
}

Here's the C# script code:

#r "Microsoft.Azure.Documents.Client"

using System.Net;
using Microsoft.Azure.Documents.Client;
using Microsoft.Azure.Documents.Linq;

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, DocumentClient client, TraceWriter log)
{
    log.Info("C# HTTP trigger function processed a request.");

    Uri collectionUri = UriFactory.CreateDocumentCollectionUri("ToDoItems", "Items");
    string searchterm = req.GetQueryNameValuePairs()
        .FirstOrDefault(q => string.Compare(q.Key, "searchterm", true) == 0)
        .Value;

    if (searchterm == null)
    {
        return req.CreateResponse(HttpStatusCode.NotFound);
    }

    log.Info($"Searching for word: {searchterm} using Uri: {collectionUri.ToString()}");
    IDocumentQuery<ToDoItem> query = client.CreateDocumentQuery<ToDoItem>(collectionUri)
        .Where(p => p.Description.Contains(searchterm))
        .AsDocumentQuery();

    while (query.HasMoreResults)
    {
        foreach (ToDoItem result in await query.ExecuteNextAsync())
        {
            log.Info(result.Description);
        }
    }
    return req.CreateResponse(HttpStatusCode.OK);
}

Azure Cosmos DB v1 output

This section contains the following examples:

Queue trigger, write one doc
Queue trigger, write docs using IAsyncCollector

Queue trigger, write one doc

{
    "name": "John Henry",
    "employeeId": "123456",
    "address": "A town nearby"
}

The function creates Azure Cosmos DB documents in the following format for each record:

{
    "id": "John Henry-123456",
    "name": "John Henry",
    "employeeId": "123456",
    "address": "A town nearby"
}

Here's the binding data in the function.json file:

{
    "name": "employeeDocument",
    "type": "documentDB",
    "databaseName": "MyDatabase",
    "collectionName": "MyCollection",
    "createIfNotExists": true,
    "connection": "MyAccount_COSMOSDB",
    "direction": "out"
}

Here's the C# script code:

    #r "Newtonsoft.Json"

    using Microsoft.Azure.WebJobs.Host;
    using Newtonsoft.Json.Linq;

    public static void Run(string myQueueItem, out object employeeDocument, TraceWriter log)
    {
        log.Info($"C# Queue trigger function processed: {myQueueItem}");

        dynamic employee = JObject.Parse(myQueueItem);

        employeeDocument = new {
            id = employee.name + "-" + employee.employeeId,
            name = employee.name,
            employeeId = employee.employeeId,
            address = employee.address
        };
    }

Queue trigger, write docs using IAsyncCollector

To create multiple documents, you can bind to ICollector<T> or IAsyncCollector<T> where T is one of the supported types.

This example refers to a simple ToDoItem type:

namespace CosmosDBSamplesV1
{
    public class ToDoItem
    {
        public string Id { get; set; }
        public string Description { get; set; }
    }
}

Here's the function.json file:

{
  "bindings": [
    {
      "name": "toDoItemsIn",
      "type": "queueTrigger",
      "direction": "in",
      "queueName": "todoqueueforwritemulti",
      "connection": "AzureWebJobsStorage"
    },
    {
      "type": "documentDB",
      "name": "toDoItemsOut",
      "databaseName": "ToDoItems",
      "collectionName": "Items",
      "connection": "CosmosDBConnection",
      "direction": "out"
    }
  ],
  "disabled": false
}

Here's the C# script code:

using System;

public static async Task Run(ToDoItem[] toDoItemsIn, IAsyncCollector<ToDoItem> toDoItemsOut, TraceWriter log)
{
    log.Info($"C# Queue trigger function processed {toDoItemsIn?.Length} items");

    foreach (ToDoItem toDoItem in toDoItemsIn)
    {
        log.Info($"Description={toDoItem.Description}");
        await toDoItemsOut.AddAsync(toDoItem);
    }
}

Azure SQL trigger

More samples for the Azure SQL trigger are available in the GitHub repository.

The example refers to a ToDoItem class and a corresponding database table:

namespace AzureSQL.ToDo
{
    public class ToDoItem
    {
        public Guid Id { get; set; }
        public int? order { get; set; }
        public string title { get; set; }
        public string url { get; set; }
        public bool? completed { get; set; }
    }
}

CREATE TABLE dbo.ToDo (
    [Id] UNIQUEIDENTIFIER PRIMARY KEY,
    [order] INT NULL,
    [title] NVARCHAR(200) NOT NULL,
    [url] NVARCHAR(200) NOT NULL,
    [completed] BIT NOT NULL
);

Change tracking is enabled on the database and on the table:

ALTER DATABASE [SampleDatabase]
SET CHANGE_TRACKING = ON
(CHANGE_RETENTION = 2 DAYS, AUTO_CLEANUP = ON);

ALTER TABLE [dbo].[ToDo]
ENABLE CHANGE_TRACKING;

The SQL trigger binds to a IReadOnlyList<SqlChange<T>>, a list of SqlChange objects each with two properties:

Item: the item that was changed. The type of the item should follow the table schema as seen in the ToDoItem class.
Operation: a value from SqlChangeOperation enum. The possible values are Insert, Update, and Delete.

The following example shows a SQL trigger in a function.json file and a C# script function that is invoked when there are changes to the ToDo table:

The following is binding data in the function.json file:

{
    "name": "todoChanges",
    "type": "sqlTrigger",
    "direction": "in",
    "tableName": "dbo.ToDo",
    "connectionStringSetting": "SqlConnectionString"
}

The following is the C# script function:

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

public static void Run(IReadOnlyList<SqlChange<ToDoItem>> todoChanges, ILogger log)
{
    log.LogInformation($"C# SQL trigger function processed a request.");

    foreach (SqlChange<ToDoItem> change in todoChanges)
    {
        ToDoItem toDoItem = change.Item;
        log.LogInformation($"Change operation: {change.Operation}");
        log.LogInformation($"Id: {toDoItem.Id}, Title: {toDoItem.title}, Url: {toDoItem.url}, Completed: {toDoItem.completed}");
    }
}

Azure SQL input

More samples for the Azure SQL input binding are available in the GitHub repository.

This section contains the following examples:

HTTP trigger, get row by ID from query string
HTTP trigger, delete rows

The examples refer to a ToDoItem class and a corresponding database table:

namespace AzureSQL.ToDo
{
    public class ToDoItem
    {
        public Guid Id { get; set; }
        public int? order { get; set; }
        public string title { get; set; }
        public string url { get; set; }
        public bool? completed { get; set; }
    }
}

CREATE TABLE dbo.ToDo (
    [Id] UNIQUEIDENTIFIER PRIMARY KEY,
    [order] INT NULL,
    [title] NVARCHAR(200) NOT NULL,
    [url] NVARCHAR(200) NOT NULL,
    [completed] BIT NOT NULL
);

HTTP trigger, get row by ID from query string

The following example shows an Azure SQL input binding in a function.json file and a C# script function that uses the binding. The function is triggered by an HTTP request that uses a query string to specify the ID. That ID is used to retrieve a ToDoItem record with the specified query.

Note

The HTTP query string parameter is case-sensitive.

Here's the binding data in the function.json file:

{
    "authLevel": "anonymous",
    "type": "httpTrigger",
    "direction": "in",
    "name": "req",
    "methods": [
        "get"
    ]
},
{
    "type": "http",
    "direction": "out",
    "name": "res"
},
{
    "name": "todoItem",
    "type": "sql",
    "direction": "in",
    "commandText": "select [Id], [order], [title], [url], [completed] from dbo.ToDo where Id = @Id",
    "commandType": "Text",
    "parameters": "@Id = {Query.id}",
    "connectionStringSetting": "SqlConnectionString"
}

Here's the C# script code:

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;
using System.Collections.Generic;

public static IActionResult Run(HttpRequest req, ILogger log, IEnumerable<ToDoItem> todoItem)
{
    return new OkObjectResult(todoItem);
}

HTTP trigger, delete rows

The following example shows an Azure SQL input binding in a function.json file and a C# script function that uses the binding to execute a stored procedure with input from the HTTP request query parameter. In this example, the stored procedure deletes a single record or all records depending on the value of the parameter.

The stored procedure dbo.DeleteToDo must be created on the SQL database.

CREATE PROCEDURE [dbo].[DeleteToDo]
    @Id NVARCHAR(100)
AS
    DECLARE @UID UNIQUEIDENTIFIER = TRY_CAST(@ID AS UNIQUEIDENTIFIER)
    IF @UId IS NOT NULL AND @Id != ''
    BEGIN
        DELETE FROM dbo.ToDo WHERE Id = @UID
    END
    ELSE
    BEGIN
        DELETE FROM dbo.ToDo WHERE @ID = ''
    END

    SELECT [Id], [order], [title], [url], [completed] FROM dbo.ToDo
GO

Here's the binding data in the function.json file:

{
    "authLevel": "anonymous",
    "type": "httpTrigger",
    "direction": "in",
    "name": "req",
    "methods": [
        "get"
    ]
},
{
    "type": "http",
    "direction": "out",
    "name": "res"
},
{
    "name": "todoItems",
    "type": "sql",
    "direction": "in",
    "commandText": "DeleteToDo",
    "commandType": "StoredProcedure",
    "parameters": "@Id = {Query.id}",
    "connectionStringSetting": "SqlConnectionString"
}

using System;
using System.Collections.Generic;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.WebJobs;
using Microsoft.Azure.WebJobs.Extensions.Http;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace AzureSQL.ToDo
{
    public static class DeleteToDo
    {
        // delete all items or a specific item from querystring
        // returns remaining items
        // uses input binding with a stored procedure DeleteToDo to delete items and return remaining items
        [FunctionName("DeleteToDo")]
        public static IActionResult Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "delete", Route = "DeleteFunction")] HttpRequest req,
            ILogger log,
            [Sql(commandText: "DeleteToDo", commandType: System.Data.CommandType.StoredProcedure, 
                parameters: "@Id={Query.id}", connectionStringSetting: "SqlConnectionString")] 
                IEnumerable<ToDoItem> toDoItems)
        {
            return new OkObjectResult(toDoItems);
        }
    }
}

Here's the C# script code:

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;
using System.Collections.Generic;

public static IActionResult Run(HttpRequest req, ILogger log, IEnumerable<ToDoItem> todoItems)
{
    return new OkObjectResult(todoItems);
}

Azure SQL output

More samples for the Azure SQL output binding are available in the GitHub repository.

This section contains the following examples:

HTTP trigger, write records to a table
HTTP trigger, write to two tables

The examples refer to a ToDoItem class and a corresponding database table:

namespace AzureSQL.ToDo
{
    public class ToDoItem
    {
        public Guid Id { get; set; }
        public int? order { get; set; }
        public string title { get; set; }
        public string url { get; set; }
        public bool? completed { get; set; }
    }
}

CREATE TABLE dbo.ToDo (
    [Id] UNIQUEIDENTIFIER PRIMARY KEY,
    [order] INT NULL,
    [title] NVARCHAR(200) NOT NULL,
    [url] NVARCHAR(200) NOT NULL,
    [completed] BIT NOT NULL
);

HTTP trigger, write records to a table

The following example shows a SQL output binding in a function.json file and a C# script function that adds records to a table, using data provided in an HTTP POST request as a JSON body.

The following is binding data in the function.json file:

{
    "authLevel": "anonymous",
    "type": "httpTrigger",
    "direction": "in",
    "name": "req",
    "methods": [
        "post"
    ]
},
{
    "type": "http",
    "direction": "out",
    "name": "res"
},
{
    "name": "todoItem",
    "type": "sql",
    "direction": "out",
    "commandText": "dbo.ToDo",
    "connectionStringSetting": "SqlConnectionString"
}

The following is sample C# script code:

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

public static IActionResult Run(HttpRequest req, ILogger log, out ToDoItem todoItem)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    string requestBody = new StreamReader(req.Body).ReadToEnd();
    todoItem = JsonConvert.DeserializeObject<ToDoItem>(requestBody);

    return new OkObjectResult(todoItem);
}

HTTP trigger, write to two tables

The following example shows a SQL output binding in a function.json file and a C# script function that adds records to a database in two different tables (dbo.ToDo and dbo.RequestLog), using data provided in an HTTP POST request as a JSON body and multiple output bindings.

The second table, dbo.RequestLog, corresponds to the following definition:

CREATE TABLE dbo.RequestLog (
    Id int identity(1,1) primary key,
    RequestTimeStamp datetime2 not null,
    ItemCount int not null
)

The following is binding data in the function.json file:

{
    "authLevel": "anonymous",
    "type": "httpTrigger",
    "direction": "in",
    "name": "req",
    "methods": [
        "post"
    ]
},
{
    "type": "http",
    "direction": "out",
    "name": "res"
},
{
    "name": "todoItem",
    "type": "sql",
    "direction": "out",
    "commandText": "dbo.ToDo",
    "connectionStringSetting": "SqlConnectionString"
},
{
    "name": "requestLog",
    "type": "sql",
    "direction": "out",
    "commandText": "dbo.RequestLog",
    "connectionStringSetting": "SqlConnectionString"
}

The following is sample C# script code:

#r "Newtonsoft.Json"

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Primitives;
using Newtonsoft.Json;

public static IActionResult Run(HttpRequest req, ILogger log, out ToDoItem todoItem, out RequestLog requestLog)
{
    log.LogInformation("C# HTTP trigger function processed a request.");

    string requestBody = new StreamReader(req.Body).ReadToEnd();
    todoItem = JsonConvert.DeserializeObject<ToDoItem>(requestBody);

    requestLog = new RequestLog();
    requestLog.RequestTimeStamp = DateTime.Now;
    requestLog.ItemCount = 1;

    return new OkObjectResult(todoItem);
}

public class RequestLog {
    public DateTime RequestTimeStamp { get; set; }
    public int ItemCount { get; set; }
}

RabbitMQ output

The following example shows a RabbitMQ output binding in a function.json file and a C# script function that uses the binding. The function reads in the message from an HTTP trigger and outputs it to the RabbitMQ queue.

Here's the binding data in the function.json file:

{
    "bindings": [
        {
            "type": "httpTrigger",
            "direction": "in",
            "authLevel": "function",
            "name": "input",
            "methods": [
                "get",
                "post"
            ]
        },
        {
            "type": "rabbitMQ",
            "name": "outputMessage",
            "queueName": "outputQueue",
            "connectionStringSetting": "rabbitMQConnectionAppSetting",
            "direction": "out"
        }
    ]
}

Here's the C# script code:

using System;
using Microsoft.Extensions.Logging;

public static void Run(string input, out string outputMessage, ILogger log)
{
    log.LogInformation(input);
    outputMessage = input;
}

SendGrid output

The following example shows a SendGrid output binding in a function.json file and a C# script function that uses the binding.

Here's the binding data in the function.json file:

{
    "bindings": [
        {
          "type": "queueTrigger",
          "name": "mymsg",
          "queueName": "myqueue",
          "connection": "AzureWebJobsStorage",
          "direction": "in"
        },
        {
          "type": "sendGrid",
          "name": "$return",
          "direction": "out",
          "apiKey": "SendGridAPIKeyAsAppSetting",
          "from": "{FromEmail}",
          "to": "{ToEmail}"
        }
    ]
}

Here's the C# script code:

#r "SendGrid"

using System;
using SendGrid.Helpers.Mail;
using Microsoft.Azure.WebJobs.Host;

public static SendGridMessage Run(Message mymsg, ILogger log)
{
    SendGridMessage message = new SendGridMessage()
    {
        Subject = $"{mymsg.Subject}"
    };
    
    message.AddContent("text/plain", $"{mymsg.Content}");

    return message;
}
public class Message
{
    public string ToEmail { get; set; }
    public string FromEmail { get; set; }
    public string Subject { get; set; }
    public string Content { get; set; }
}

SignalR trigger

Here's example binding data in the function.json file:

{
    "type": "signalRTrigger",
    "name": "invocation",
    "hubName": "SignalRTest",
    "category": "messages",
    "event": "SendMessage",
    "parameterNames": [
        "message"
    ],
    "direction": "in"
}

And, here's the code:

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using System;
using Microsoft.Azure.WebJobs.Extensions.SignalRService;
using Microsoft.Extensions.Logging;

public static void Run(InvocationContext invocation, string message, ILogger logger)
{
    logger.LogInformation($"Receive {message} from {invocationContext.ConnectionId}.");
}

SignalR input

The following example shows a SignalR connection info input binding in a function.json file and a C# Script function that uses the binding to return the connection information.

Here's binding data in the function.json file:

Example function.json:

{
    "type": "signalRConnectionInfo",
    "name": "connectionInfo",
    "hubName": "chat",
    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
    "direction": "in"
}

Here's the C# Script code:

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using Microsoft.Azure.WebJobs.Extensions.SignalRService;

public static SignalRConnectionInfo Run(HttpRequest req, SignalRConnectionInfo connectionInfo)
{
    return connectionInfo;
}

You can set the userId property of the binding to the value from either header using a binding expression: {headers.x-ms-client-principal-id} or {headers.x-ms-client-principal-name}.

Example function.json:

{
    "type": "signalRConnectionInfo",
    "name": "connectionInfo",
    "hubName": "chat",
    "userId": "{headers.x-ms-client-principal-id}",
    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
    "direction": "in"
}

Here's the C# Script code:

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using Microsoft.Azure.WebJobs.Extensions.SignalRService;

public static SignalRConnectionInfo Run(HttpRequest req, SignalRConnectionInfo connectionInfo)
{
    // connectionInfo contains an access key token with a name identifier
    // claim set to the authenticated user
    return connectionInfo;
}

SignalR output

Here's binding data in the function.json file:

Example function.json:

{
  "type": "signalR",
  "name": "signalRMessages",
  "hubName": "<hub_name>",
  "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
  "direction": "out"
}

Here's the C# Script code:

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using Microsoft.Azure.WebJobs.Extensions.SignalRService;

public static Task Run(
    object message,
    IAsyncCollector<SignalRMessage> signalRMessages)
{
    return signalRMessages.AddAsync(
        new SignalRMessage
        {
            Target = "newMessage",
            Arguments = new [] { message }
        });
}

You can send a message only to connections that have been authenticated to a user by setting the user ID in the SignalR message.

Example function.json:

{
  "type": "signalR",
  "name": "signalRMessages",
  "hubName": "<hub_name>",
  "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
  "direction": "out"
}

Here's the C# script code:

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using Microsoft.Azure.WebJobs.Extensions.SignalRService;

public static Task Run(
    object message,
    IAsyncCollector<SignalRMessage> signalRMessages)
{
    return signalRMessages.AddAsync(
        new SignalRMessage
        {
            // the message will only be sent to this user ID
            UserId = "userId1",
            Target = "newMessage",
            Arguments = new [] { message }
        });
}

You can send a message only to connections that have been added to a group by setting the group name in the SignalR message.

Example function.json:

{
  "type": "signalR",
  "name": "signalRMessages",
  "hubName": "<hub_name>",
  "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
  "direction": "out"
}

Here's the C# Script code:

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using Microsoft.Azure.WebJobs.Extensions.SignalRService;

public static Task Run(
    object message,
    IAsyncCollector<SignalRMessage> signalRMessages)
{
    return signalRMessages.AddAsync(
        new SignalRMessage
        {
            // the message will be sent to the group with this name
            GroupName = "myGroup",
            Target = "newMessage",
            Arguments = new [] { message }
        });
}

SignalR Service allows users or connections to be added to groups. Messages can then be sent to a group. You can use the SignalR output binding to manage groups.

The following example adds a user to a group.

Example function.json

{
    "type": "signalR",
    "name": "signalRGroupActions",
    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
    "hubName": "chat",
    "direction": "out"
}

Run.csx

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using Microsoft.Azure.WebJobs.Extensions.SignalRService;

public static Task Run(
    HttpRequest req,
    ClaimsPrincipal claimsPrincipal,
    IAsyncCollector<SignalRGroupAction> signalRGroupActions)
{
    var userIdClaim = claimsPrincipal.FindFirst(ClaimTypes.NameIdentifier);
    return signalRGroupActions.AddAsync(
        new SignalRGroupAction
        {
            UserId = userIdClaim.Value,
            GroupName = "myGroup",
            Action = GroupAction.Add
        });
}

The following example removes a user from a group.

Example function.json

{
    "type": "signalR",
    "name": "signalRGroupActions",
    "connectionStringSetting": "<name of setting containing SignalR Service connection string>",
    "hubName": "chat",
    "direction": "out"
}

Run.csx

#r "Microsoft.Azure.WebJobs.Extensions.SignalRService"
using Microsoft.Azure.WebJobs.Extensions.SignalRService;

public static Task Run(
    HttpRequest req,
    ClaimsPrincipal claimsPrincipal,
    IAsyncCollector<SignalRGroupAction> signalRGroupActions)
{
    var userIdClaim = claimsPrincipal.FindFirst(ClaimTypes.NameIdentifier);
    return signalRGroupActions.AddAsync(
        new SignalRGroupAction
        {
            UserId = userIdClaim.Value,
            GroupName = "myGroup",
            Action = GroupAction.Remove
        });
}

Twilio output

The following example shows a Twilio output binding in a function.json file and a C# script function that uses the binding. The function uses an out parameter to send a text message.

Here's binding data in the function.json file:

Example function.json:

{
  "type": "twilioSms",
  "name": "message",
  "accountSidSetting": "TwilioAccountSid",
  "authTokenSetting": "TwilioAuthToken",
  "from": "+1425XXXXXXX",
  "direction": "out",
  "body": "Azure Functions Testing"
}

Here's C# script code:

#r "Newtonsoft.Json"
#r "Twilio"
#r "Microsoft.Azure.WebJobs.Extensions.Twilio"

using System;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Microsoft.Azure.WebJobs.Extensions.Twilio;
using Twilio.Rest.Api.V2010.Account;
using Twilio.Types;

public static void Run(string myQueueItem, out CreateMessageOptions message,  ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");

    // In this example the queue item is a JSON string representing an order that contains the name of a
    // customer and a mobile number to send text updates to.
    dynamic order = JsonConvert.DeserializeObject(myQueueItem);
    string msg = "Hello " + order.name + ", thank you for your order.";

    // You must initialize the CreateMessageOptions variable with the "To" phone number.
    message = new CreateMessageOptions(new PhoneNumber("+1704XXXXXXX"));

    // A dynamic message can be set instead of the body in the output binding. In this example, we use
    // the order information to personalize a text message.
    message.Body = msg;
}

You can't use out parameters in asynchronous code. Here's an asynchronous C# script code example:

#r "Newtonsoft.Json"
#r "Twilio"
#r "Microsoft.Azure.WebJobs.Extensions.Twilio"

using System;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using Microsoft.Azure.WebJobs.Extensions.Twilio;
using Twilio.Rest.Api.V2010.Account;
using Twilio.Types;

public static async Task Run(string myQueueItem, IAsyncCollector<CreateMessageOptions> message,  ILogger log)
{
    log.LogInformation($"C# Queue trigger function processed: {myQueueItem}");

    // In this example the queue item is a JSON string representing an order that contains the name of a
    // customer and a mobile number to send text updates to.
    dynamic order = JsonConvert.DeserializeObject(myQueueItem);
    string msg = "Hello " + order.name + ", thank you for your order.";

    // You must initialize the CreateMessageOptions variable with the "To" phone number.
    CreateMessageOptions smsText = new CreateMessageOptions(new PhoneNumber("+1704XXXXXXX"));

    // A dynamic message can be set instead of the body in the output binding. In this example, we use
    // the order information to personalize a text message.
    smsText.Body = msg;

    await message.AddAsync(smsText);
}

Warmup trigger

The following example shows a warmup trigger in a function.json file and a C# script function that runs on each new instance when it's added to your app.

Not supported for version 1.x of the Functions runtime.

Here's the function.json file:

{
    "bindings": [
        {
            "type": "warmupTrigger",
            "direction": "in",
            "name": "warmupContext"
        }
    ]
}

public static void Run(WarmupContext warmupContext, ILogger log)
{
    log.LogInformation("Function App instance is warm.");  
}

Next steps

Learn more about triggers and bindings

Learn more about best practices for Azure Functions

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Azure Functions C# script (.csx) developer reference

How .csx works

Folder structure

Binding to arguments

Supported types for bindings

Referencing custom classes

Reusing .csx code

Binding to method return value

Writing multiple output values

Logging

Custom metrics logging

Async

Cancellation tokens

Importing namespaces

Referencing external assemblies

Referencing custom assemblies

Watched directories

Using NuGet packages

Environment variables

Retry policies

Binding at runtime

Single attribute example

Multiple attributes example

Convert a C# script app to a C# project

Example function conversion

Binding configuration and examples

Blob trigger

Blob input

Blob output

RabbitMQ trigger

Queue trigger

Queue output

Table input

Table output

Timer trigger

HTTP trigger

HTTP output

Event Hubs trigger

Event Hubs output

Event Grid trigger

Event Grid output

Service Bus trigger

Service Bus output

Azure Cosmos DB v2 trigger

Azure Cosmos DB v2 input

Queue trigger, look up ID from string

Queue trigger, get multiple docs, using SqlQuery

HTTP trigger, look up ID from query string

HTTP trigger, look up ID from route data

HTTP trigger, get multiple docs, using SqlQuery

HTTP trigger, get multiple docs, using DocumentClient

Azure Cosmos DB v2 output

Queue trigger, write one doc

Queue trigger, write docs using IAsyncCollector

Azure Cosmos DB v1 trigger

Azure Cosmos DB v1 input

Queue trigger, look up ID from string

Queue trigger, get multiple docs, using SqlQuery

HTTP trigger, look up ID from query string

HTTP trigger, look up ID from route data

HTTP trigger, get multiple docs, using SqlQuery

HTTP trigger, get multiple docs, using DocumentClient

Azure Cosmos DB v1 output

Queue trigger, write one doc

Queue trigger, write docs using IAsyncCollector

Azure SQL trigger

Azure SQL input

HTTP trigger, get row by ID from query string

HTTP trigger, delete rows

Azure SQL output

HTTP trigger, write records to a table

HTTP trigger, write to two tables

RabbitMQ output

SendGrid output

SignalR trigger

SignalR input

SignalR output

Twilio output

Warmup trigger