Quickstart: Send and receive messages from an Azure Service Bus queue (.NET)

In this quickstart, you'll do the following steps:

  1. Create a Service Bus namespace, using the Azure portal.
  2. Create a Service Bus queue, using the Azure portal.
  3. Write a .NET console application to send a set of messages to the queue.
  4. Write a .NET console application to receive those messages from the queue.

Note

This quick start provides step-by-step instructions to implement a simple scenario of sending a batch of messages to a Service Bus queue and then receiving them. For an overview of the .NET client library, see Azure Service Bus client library for .NET. For more samples, see Service Bus .NET samples on GitHub.

Prerequisites

If you're new to the service, see Service Bus overview before you do this quickstart.

  • Azure subscription. To use Azure services, including Azure Service Bus, you need a subscription. If you don't have an existing Azure account, you can sign up for a free trial.
  • Visual Studio 2022. The sample application makes use of new features that were introduced in C# 10. You can still use the Service Bus client library with previous C# language versions, but the syntax may vary. To use the latest syntax, we recommend that you install .NET 6.0 or higher and set the language version to latest. If you're using Visual Studio, versions before Visual Studio 2022 aren't compatible with the tools needed to build C# 10 projects.

Create a namespace in the Azure portal

To begin using Service Bus messaging entities in Azure, you must first create a namespace with a name that is unique across Azure. A namespace provides a scoping container for Service Bus resources within your application.

To create a namespace:

  1. Sign in to the Azure portal

  2. In the left navigation pane of the portal, select All services, select Integration from the list of categories, hover the mouse over Service Bus, and then select Create on the Service Bus tile.

    Image showing selection of Create a resource, Integration, and then Service Bus in the menu.

  3. In the Basics tag of the Create namespace page, follow these steps:

    1. For Subscription, choose an Azure subscription in which to create the namespace.

    2. For Resource group, choose an existing resource group in which the namespace will live, or create a new one.

    3. Enter a name for the namespace. The namespace name should adhere to the following naming conventions:

      • The name must be unique across Azure. The system immediately checks to see if the name is available.
      • The name length is at least 6 and at most 50 characters.
      • The name can contain only letters, numbers, hyphens “-“.
      • The name must start with a letter and end with a letter or number.
      • The name doesn't end with “-sb“ or “-mgmt“.
    4. For Location, choose the region in which your namespace should be hosted.

    5. For Pricing tier, select the pricing tier (Basic, Standard, or Premium) for the namespace. For this quickstart, select Standard.

      Important

      If you want to use topics and subscriptions, choose either Standard or Premium. Topics/subscriptions aren't supported in the Basic pricing tier.

      If you selected the Premium pricing tier, specify the number of messaging units. The premium tier provides resource isolation at the CPU and memory level so that each workload runs in isolation. This resource container is called a messaging unit. A premium namespace has at least one messaging unit. You can select 1, 2, 4, 8 or 16 messaging units for each Service Bus Premium namespace. For more information, see Service Bus Premium Messaging.

    6. Select Review + create at the bottom of the page.

      Image showing the Create a namespace page

    7. On the Review + create page, review settings, and select Create.

  4. Once the deployment of the resource is successful, select Go to resource on the deployment page.

    Image showing the deployment succeeded page with the Go to resource link.

  5. You see the home page for your service bus namespace.

    Image showing the home page of the Service Bus namespace created.

Create a queue in the Azure portal

  1. On the Service Bus Namespace page, select Queues in the left navigational menu.

  2. On the Queues page, select + Queue on the toolbar.

  3. Enter a name for the queue, and leave the other values with their defaults.

  4. Now, select Create.

    Image showing creation of a queue in the portal

Authenticate the app to Azure

This quick start shows you two ways of connecting to Azure Service Bus: passwordless and connection string. The first option shows you how to use your security principal in Azure Active Directory and role-based access control (RBAC) to connect to a Service Bus namespace. You don't need to worry about having hard-coded connection string in your code or in a configuration file or in a secure storage like Azure Key Vault. The second option shows you how to use a connection string to connect to a Service Bus namespace. If you are new to Azure, you may find the connection string option easier to follow. We recommend using the passwordless option in real-world applications and production environments. For more information, see Authentication and authorization. You can also read more about passwordless authentication on the overview page.

Assign roles to your Azure AD user

When developing locally, make sure that the user account that connects to Azure Service Bus has the correct permissions. You'll need the Azure Service Bus Data Owner role in order to send and receive messages. To assign yourself this role, you'll need the User Access Administrator role, or another role that includes the Microsoft.Authorization/roleAssignments/write action. You can assign Azure RBAC roles to a user using the Azure portal, Azure CLI, or Azure PowerShell. Learn more about the available scopes for role assignments on the scope overview page.

The following example assigns the Azure Service Bus Data Owner role to your user account, which provides full access to Azure Service Bus resources. In a real scenario, follow the Principle of Least Privilege to give users only the minimum permissions needed for a more secure production environment.

Azure built-in roles for Azure Service Bus

For Azure Service Bus, the management of namespaces and all related resources through the Azure portal and the Azure resource management API is already protected using the Azure RBAC model. Azure provides the below Azure built-in roles for authorizing access to a Service Bus namespace:

  • Azure Service Bus Data Owner: Enables data access to Service Bus namespace and its entities (queues, topics, subscriptions, and filters). A member of this role can send and receive messages from queues or topics/subscriptions.
  • Azure Service Bus Data Sender: Use this role to give the send access to Service Bus namespace and its entities.
  • Azure Service Bus Data Receiver: Use this role to give the receive access to Service Bus namespace and its entities.

If you want to create a custom role, see Rights required for Service Bus operations.

Add Azure AD user to Azure Service Bus Owner role

Add your Azure AD user name to the Azure Service Bus Data Owner role at the Service Bus namespace level. It will allow an app running in the context of your user account to send messages to a queue or a topic, and receive messages from a queue or a topic's subscription.

Important

In most cases, it will take a minute or two for the role assignment to propagate in Azure. In rare cases, it may take up to eight minutes. If you receive authentication errors when you first run your code, wait a few moments and try again.

  1. If you don't have the Service Bus Namespace page open in the Azure portal, locate your Service Bus namespace using the main search bar or left navigation.

  2. On the overview page, select Access control (IAM) from the left-hand menu.

  3. On the Access control (IAM) page, select the Role assignments tab.

  4. Select + Add from the top menu and then Add role assignment from the resulting drop-down menu.

    A screenshot showing how to assign a role.

  5. Use the search box to filter the results to the desired role. For this example, search for Azure Service Bus Data Owner and select the matching result. Then choose Next.

  6. Under Assign access to, select User, group, or service principal, and then choose + Select members.

  7. In the dialog, search for your Azure AD username (usually your user@domain email address) and then choose Select at the bottom of the dialog.

  8. Select Review + assign to go to the final page, and then Review + assign again to complete the process.

Launch Visual Studio and sign-in to Azure

You can authorize access to the service bus namespace using the following steps:

  1. Launch Visual Studio. If you see the Get started window, select the Continue without code link in the right pane.

  2. Select the Sign in button in the top right of Visual Studio.

    Screenshot showing the button to sign in to Azure using Visual Studio.

  3. Sign-in using the Azure AD account you assigned a role to previously.

    Screenshot showing the account selection.

Send messages to the queue

This section shows you how to create a .NET console application to send messages to a Service Bus queue.

Note

This quick start provides step-by-step instructions to implement a simple scenario of sending a batch of messages to a Service Bus queue and then receiving them. For more samples on other and advanced scenarios, see Service Bus .NET samples on GitHub.

Create a console application

  1. In Visual Studio, select File -> New -> Project menu.

  2. On the Create a new project dialog box, do the following steps: If you don't see this dialog box, select File on the menu, select New, and then select Project.

    1. Select C# for the programming language.

    2. Select Console for the type of the application.

    3. Select Console App from the results list.

    4. Then, select Next.

      Image showing the Create a new project dialog box with C# and Console selected

  3. Enter QueueSender for the project name, ServiceBusQueueQuickStart for the solution name, and then select Next.

    Image showing the solution and project names in the Configure your new project dialog box

  4. On the Additional information page, select Create to create the solution and the project.

Add the NuGet packages to the project

  1. Select Tools > NuGet Package Manager > Package Manager Console from the menu.

  2. Run the following command to install the Azure.Messaging.ServiceBus NuGet package.

    Install-Package Azure.Messaging.ServiceBus
    
  3. Run the following command to install the Azure.Identity NuGet package.

    Install-Package Azure.Identity
    

Add code to send messages to the queue

  1. Replace the contents of Program.cs with the following code. The important steps are outlined below, with additional information in the code comments.

    Important

    Update placeholder values (<NAMESPACE-CONNECTION-STRING> and <QUEUE-NAME>) in the code snippet with names of your Service Bus namespace and queue.

    using Azure.Messaging.ServiceBus;
    using Azure.Identity;
    
    // name of your Service Bus queue
    // the client that owns the connection and can be used to create senders and receivers
    ServiceBusClient client;
    
    // the sender used to publish messages to the queue
    ServiceBusSender sender;
    
    // number of messages to be sent to the queue
    const int numOfMessages = 3;
    
    // The Service Bus client types are safe to cache and use as a singleton for the lifetime
    // of the application, which is best practice when messages are being published or read
    // regularly.
    //
    // Set the transport type to AmqpWebSockets so that the ServiceBusClient uses the port 443. 
    // If you use the default AmqpTcp, ensure that ports 5671 and 5672 are open.
    var clientOptions = new ServiceBusClientOptions
    { 
        TransportType = ServiceBusTransportType.AmqpWebSockets
    };
    //TODO: Replace the "<NAMESPACE-NAME>" and "<QUEUE-NAME>" placeholders.
    client = new ServiceBusClient(
        "<NAMESPACE-NAME>.servicebus.windows.net",
        new DefaultAzureCredential(),
        clientOptions);
    sender = client.CreateSender("<QUEUE-NAME>");
    
    // create a batch 
    using ServiceBusMessageBatch messageBatch = await sender.CreateMessageBatchAsync();
    
    for (int i = 1; i <= numOfMessages; i++)
    {
        // try adding a message to the batch
        if (!messageBatch.TryAddMessage(new ServiceBusMessage($"Message {i}")))
        {
            // if it is too large for the batch
            throw new Exception($"The message {i} is too large to fit in the batch.");
        }
    }
    
    try
    {
        // Use the producer client to send the batch of messages to the Service Bus queue
        await sender.SendMessagesAsync(messageBatch);
        Console.WriteLine($"A batch of {numOfMessages} messages has been published to the queue.");
    }
    finally
    {
        // Calling DisposeAsync on client types is required to ensure that network
        // resources and other unmanaged objects are properly cleaned up.
        await sender.DisposeAsync();
        await client.DisposeAsync();
    }
    
    Console.WriteLine("Press any key to end the application");
    Console.ReadKey();
    
  2. Build the project, and ensure that there are no errors.

  3. Run the program and wait for the confirmation message.

    A batch of 3 messages has been published to the queue
    

    Important

    In most cases, it will take a minute or two for the role assignment to propagate in Azure. In rare cases, it may take up to eight minutes. If you receive authentication errors when you first run your code, wait a few moments and try again.

  4. In the Azure portal, follow these steps:

    1. Navigate to your Service Bus namespace.

    2. On the Overview page, select the queue in the bottom-middle pane.

      Image showing the Service Bus Namespace page in the Azure portal with the queue selected.

    3. Notice the values in the Essentials section.

      Image showing the number of messages received and the size of the queue.

    Notice the following values:

    • The Active message count value for the queue is now 3. Each time you run this sender app without retrieving the messages, this value increases by 3.
    • The current size of the queue increments each time the app adds messages to the queue.
    • In the Messages chart in the bottom Metrics section, you can see that there are three incoming messages for the queue.

Receive messages from the queue

In this section, you'll create a .NET console application that receives messages from the queue.

Note

This quickstart provides step-by-step instructions to implement a scenario of sending a batch of messages to a Service Bus queue and then receiving them. For more samples on other and advanced scenarios, see Service Bus .NET samples on GitHub.

Create a project for the receiver

  1. In the Solution Explorer window, right-click the ServiceBusQueueQuickStart solution, point to Add, and select New Project.
  2. Select Console application, and select Next.
  3. Enter QueueReceiver for the Project name, and select Create.
  4. In the Solution Explorer window, right-click QueueReceiver, and select Set as a Startup Project.

Add the NuGet packages to the project

  1. Select Tools > NuGet Package Manager > Package Manager Console from the menu.

  2. Select QueueReceiver for Default project.

    Screenshot showing QueueReceiver project selected in the Package Manager Console.

  3. Run the following command to install the Azure.Messaging.ServiceBus NuGet package.

    Install-Package Azure.Messaging.ServiceBus
    
  4. Run the following command to install the Azure.Identity NuGet package.

    Install-Package Azure.Identity
    

Add the code to receive messages from the queue

In this section, you'll add code to retrieve messages from the queue.

  1. Within the Program class, add the following code:

    using System.Threading.Tasks;
    using Azure.Identity;
    using Azure.Messaging.ServiceBus;
    
    // the client that owns the connection and can be used to create senders and receivers
    ServiceBusClient client;
    
    // the processor that reads and processes messages from the queue
    ServiceBusProcessor processor;
    
  2. Append the following methods to the end of the Program class.

    // handle received messages
    async Task MessageHandler(ProcessMessageEventArgs args)
    {
        string body = args.Message.Body.ToString();
        Console.WriteLine($"Received: {body}");
    
        // complete the message. message is deleted from the queue. 
        await args.CompleteMessageAsync(args.Message);
    }
    
    // handle any errors when receiving messages
    Task ErrorHandler(ProcessErrorEventArgs args)
    {
        Console.WriteLine(args.Exception.ToString());
        return Task.CompletedTask;
    }
    
  3. Append the following code to the end of the Program class. The important steps are outlined below, with additional information in the code comments.

    Important

    Update placeholder values (<NAMESPACE-NAME> and <QUEUE-NAME>) in the code snippet with names of your Service Bus namespace and queue.

    // The Service Bus client types are safe to cache and use as a singleton for the lifetime
    // of the application, which is best practice when messages are being published or read
    // regularly.
    //
    // Set the transport type to AmqpWebSockets so that the ServiceBusClient uses port 443. 
    // If you use the default AmqpTcp, make sure that ports 5671 and 5672 are open.
    
    // TODO: Replace the <NAMESPACE-NAME> placeholder
    var clientOptions = new ServiceBusClientOptions()
    {
        TransportType = ServiceBusTransportType.AmqpWebSockets
    };
    client = new ServiceBusClient(
        "<NAMESPACE-NAME>.servicebus.windows.net",
        new DefaultAzureCredential(),
        clientOptions);
    
    // create a processor that we can use to process the messages
    // TODO: Replace the <QUEUE-NAME> placeholder
    processor = client.CreateProcessor("<QUEUE-NAME>", new ServiceBusProcessorOptions());
    
    try
    {
        // add handler to process messages
        processor.ProcessMessageAsync += MessageHandler;
    
        // add handler to process any errors
        processor.ProcessErrorAsync += ErrorHandler;
    
        // start processing 
        await processor.StartProcessingAsync();
    
        Console.WriteLine("Wait for a minute and then press any key to end the processing");
        Console.ReadKey();
    
        // stop processing 
        Console.WriteLine("\nStopping the receiver...");
        await processor.StopProcessingAsync();
        Console.WriteLine("Stopped receiving messages");
    }
    finally
    {
        // Calling DisposeAsync on client types is required to ensure that network
        // resources and other unmanaged objects are properly cleaned up.
        await processor.DisposeAsync();
        await client.DisposeAsync();
    }
    
  4. The completed Program class should match the following code:

    using System.Threading.Tasks;
    using Azure.Messaging.ServiceBus;
    using Azure.Identity;
    
    // the client that owns the connection and can be used to create senders and receivers
    ServiceBusClient client;
    
    // the processor that reads and processes messages from the queue
    ServiceBusProcessor processor;
    
    // The Service Bus client types are safe to cache and use as a singleton for the lifetime
    // of the application, which is best practice when messages are being published or read
    // regularly.
    //
    // Set the transport type to AmqpWebSockets so that the ServiceBusClient uses port 443.
    // If you use the default AmqpTcp, make sure that ports 5671 and 5672 are open.
    
    // TODO: Replace the <NAMESPACE-NAME> and <QUEUE-NAME> placeholders
    var clientOptions = new ServiceBusClientOptions() 
    {
        TransportType = ServiceBusTransportType.AmqpWebSockets
    };
    client = new ServiceBusClient("<NAMESPACE-NAME>.servicebus.windows.net", 
        new DefaultAzureCredential(), clientOptions);
    
    // create a processor that we can use to process the messages
    // TODO: Replace the <QUEUE-NAME> placeholder
    processor = client.CreateProcessor("<QUEUE-NAME>", new ServiceBusProcessorOptions());
    
    try
    {
        // add handler to process messages
        processor.ProcessMessageAsync += MessageHandler;
    
        // add handler to process any errors
        processor.ProcessErrorAsync += ErrorHandler;
    
        // start processing 
        await processor.StartProcessingAsync();
    
        Console.WriteLine("Wait for a minute and then press any key to end the processing");
        Console.ReadKey();
    
        // stop processing 
        Console.WriteLine("\nStopping the receiver...");
        await processor.StopProcessingAsync();
        Console.WriteLine("Stopped receiving messages");
    }
    finally
    {
        // Calling DisposeAsync on client types is required to ensure that network
        // resources and other unmanaged objects are properly cleaned up.
        await processor.DisposeAsync();
        await client.DisposeAsync();
    }
    
    // handle received messages
    async Task MessageHandler(ProcessMessageEventArgs args)
    {
        string body = args.Message.Body.ToString();
        Console.WriteLine($"Received: {body}");
    
        // complete the message. message is deleted from the queue. 
        await args.CompleteMessageAsync(args.Message);
    }
    
    // handle any errors when receiving messages
    Task ErrorHandler(ProcessErrorEventArgs args)
    {
        Console.WriteLine(args.Exception.ToString());
        return Task.CompletedTask;
    }
    
  5. Build the project, and ensure that there are no errors.

  6. Run the receiver application. You should see the received messages. Press any key to stop the receiver and the application.

    Wait for a minute and then press any key to end the processing
    Received: Message 1
    Received: Message 2
    Received: Message 3
    
    Stopping the receiver...
    Stopped receiving messages
    
  7. Check the portal again. Wait for a few minutes and refresh the page if you don't see 0 for Active messages.

    • The Active message count and Current size values are now 0.

    • In the Messages chart in the bottom Metrics section, you can see that there are three incoming messages and three outgoing messages for the queue.

      Screenshot showing active messages and size after receive.

Clean up resources

Navigate to your Service Bus namespace in the Azure portal, and select Delete on the Azure portal to delete the namespace and the queue in it.

See also

See the following documentation and samples:

Next steps