How to configure daemon apps that call web APIs

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02/01/2024

Learn how to configure the code for your daemon application that calls web APIs.

Microsoft libraries supporting daemon apps

The following Microsoft libraries support daemon apps:

Language / framework	Project on GitHub	Package	Getting started	Generally available (GA) or Public preview¹
.NET	MSAL.NET	Microsoft.Identity.Client	Quickstart	GA
Java	MSAL4J	msal4j	—	GA
Node	MSAL Node	msal-node	Quickstart	GA
Python	MSAL Python	msal-python	Quickstart	GA

¹ Universal License Terms for Online Services apply to libraries in Public preview.

Configure the authority

Daemon applications use application permissions rather than delegated permissions. So their supported account type can't be an account in any organizational directory or any personal Microsoft account (for example, Skype, Xbox, Outlook.com). There's no tenant admin to grant consent to a daemon application for a Microsoft personal account. You need to choose accounts in my organization or accounts in any organization.

The authority specified in the application configuration should be tenanted (specifying a tenant ID or a domain name associated with your organization).

Even if you want to provide a multitenant tool, you should use a tenant ID or domain name, and not common or organizations with this flow, because the service can't reliably infer which tenant should be used.

Configure and instantiate the application

In MSAL libraries, the client credentials (secret or certificate) are passed as a parameter of the confidential client application construction.

Important

Even if your application is a console application that runs as a service, if it's a daemon application, it needs to be a confidential client application.

Configuration file

The configuration file defines:

The cloud instance and tenant ID, which together make up the authority.
The client ID that you got from the application registration.
Either a client secret or a certificate.

Here's an example of defining the configuration in an appsettings.json file. This example is taken from the .NET console daemon code sample on GitHub.

{
    "AzureAd": {
        "Instance": "https://login.microsoftonline.com/",
        "TenantId": "[Enter here the tenantID or domain name for your Azure AD tenant]",
        "ClientId": "[Enter here the ClientId for your application]",
        "ClientCredentials": [
            {
                "SourceType": "ClientSecret",
                "ClientSecret": "[Enter here a client secret for your application]"
            }
        ]
    }
}

You provide a certificate instead of the client secret, or workload identity federation credentials.

 private final static String CLIENT_ID = "";
 private final static String AUTHORITY = "https://login.microsoftonline.com/<tenant>/";
 private final static String CLIENT_SECRET = "";
 private final static Set<String> SCOPE = Collections.singleton("https://graph.microsoft.com/.default");

Configuration parameters for the Node.js daemon sample are located in an .env file:

# Credentials
TENANT_ID=Enter_the_Tenant_Info_Here
CLIENT_ID=Enter_the_Application_Id_Here

// You provide either a ClientSecret or a CertificateConfiguration, or a ClientAssertion. These settings are exclusive
CLIENT_SECRET=Enter_the_Client_Secret_Here
CERTIFICATE_THUMBPRINT=Enter_the_certificate_thumbprint_Here
CERTIFICATE_PRIVATE_KEY=Enter_the_certificate_private_key_Here
CLIENT_ASSERTION=Enter_the_Assertion_String_Here

# Endpoints
// the Azure AD endpoint is the authority endpoint for token issuance
AAD_ENDPOINT=Enter_the_Cloud_Instance_Id_Here // https://login.microsoftonline.com/
// the graph endpoint is the application ID URI of Microsoft Graph
GRAPH_ENDPOINT=Enter_the_Graph_Endpoint_Here // https://graph.microsoft.com/

When you build a confidential client with client secrets, the parameters.json config file in the Python daemon sample is as follows:

{
  "authority": "https://login.microsoftonline.com/<your_tenant_id>",
  "client_id": "your_client_id",
  "scope": [ "https://graph.microsoft.com/.default" ],
  "secret": "The secret generated by Azure AD during your confidential app registration",
  "endpoint": "https://graph.microsoft.com/v1.0/users"
}

When you build a confidential client with certificates, the parameters.json config file in the Python daemon sample is as follows:

{
  "authority": "https://login.microsoftonline.com/<your_tenant_id>",
  "client_id": "your_client_id",
  "scope": [ "https://graph.microsoft.com/.default" ],
  "thumbprint": "790E... The thumbprint generated by Azure AD when you upload your public cert",
  "private_key_file": "server.pem",
  "endpoint": "https://graph.microsoft.com/v1.0/users"
}

Here's an example of defining the configuration in an appsettings.json file. This example is taken from the .NET console daemon code sample on GitHub.

{
  "Instance": "https://login.microsoftonline.com/{0}",
  "Tenant": "[Enter here the tenantID or domain name for your Azure AD tenant]",
  "ClientId": "[Enter here the ClientId for your application]",
  "ClientSecret": "[Enter here a client secret for your application]",
  "CertificateName": "[Or instead of client secret: Enter here the name of a certificate (from the user cert store) as registered with your application]"
}

You provide either a ClientSecret or a CertificateName. These settings are exclusive.

Instantiate the MSAL application

To instantiate the MSAL application, add, reference, or import the MSAL package (depending on the language).

The construction is different, depending on whether you're using client secrets or certificates (or, as an advanced scenario, signed assertions).

Reference the package

Reference the MSAL package in your application code.

Add the Microsoft.Identity.Web.TokenAcquisition NuGet package to your application. Alternatively, if you want to call Microsoft Graph, add the Microsoft.Identity.Web.GraphServiceClient package. Your project could be as follows. The appsettings.json file needs to be copied to the output directory.

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net7.0</TargetFramework>
    <RootNamespace>daemon_console</RootNamespace>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.Identity.Web.GraphServiceClient" Version="2.12.2" />
  </ItemGroup>

  <ItemGroup>
    <None Update="appsettings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
  </ItemGroup>
</Project>

In the Program.cs file, add a using directive in your code to reference Microsoft.Identity.Web.

using Microsoft.Identity.Abstractions;
using Microsoft.Identity.Web;

import com.microsoft.aad.msal4j.ClientCredentialFactory;
import com.microsoft.aad.msal4j.ClientCredentialParameters;
import com.microsoft.aad.msal4j.ConfidentialClientApplication;
import com.microsoft.aad.msal4j.IAuthenticationResult;
import com.microsoft.aad.msal4j.IClientCredential;
import com.microsoft.aad.msal4j.MsalException;
import com.microsoft.aad.msal4j.SilentParameters;

Install the packages by running npm install in the folder where package.json file resides. Then, import the msal-node package:

const msal = require('@azure/msal-node');

import msal
import json
import sys
import logging

Add the Microsoft.Identity.Client NuGet package to your application, and then add a using directive in your code to reference it.

In MSAL.NET, the confidential client application is represented by the IConfidentialClientApplication interface.

using Microsoft.Identity.Client;
IConfidentialClientApplication app;

Instantiate the confidential client application with a client secret

Here's the code to instantiate the confidential client application with a client secret:

   class Program
    {
        static async Task Main(string[] _)
        {
            // Get the Token acquirer factory instance. By default it reads an appsettings.json
            // file if it exists in the same folder as the app (make sure that the 
            // "Copy to Output Directory" property of the appsettings.json file is "Copy if newer").
            TokenAcquirerFactory tokenAcquirerFactory = TokenAcquirerFactory.GetDefaultInstance();

            // Configure the application options to be read from the configuration
            // and add the services you need (Graph, token cache)
            IServiceCollection services = tokenAcquirerFactory.Services;
            services.AddMicrosoftGraph();
            // By default, you get an in-memory token cache.
            // For more token cache serialization options, see https://aka.ms/msal-net-token-cache-serialization

            // Resolve the dependency injection.
            var serviceProvider = tokenAcquirerFactory.Build();

            // ...
        }
    }

The configuration is read from the appsettings.json:

IClientCredential credential = ClientCredentialFactory.createFromSecret(CLIENT_SECRET);

ConfidentialClientApplication cca =
        ConfidentialClientApplication
                .builder(CLIENT_ID, credential)
                .authority(AUTHORITY)
                .build();


const msalConfig = {
  auth: {
    clientId: process.env.CLIENT_ID,
    authority: process.env.AAD_ENDPOINT + process.env.TENANT_ID,
    clientSecret: process.env.CLIENT_SECRET,
  }
};

const apiConfig = {
  uri: process.env.GRAPH_ENDPOINT + 'v1.0/users',
};

const tokenRequest = {
  scopes: [process.env.GRAPH_ENDPOINT + '.default'],
};

const cca = new msal.ConfidentialClientApplication(msalConfig);

# Pass the parameters.json file as an argument to this Python script. E.g.: python your_py_file.py parameters.json
config = json.load(open(sys.argv[1]))

# Create a preferably long-lived app instance that maintains a token cache.
app = msal.ConfidentialClientApplication(
    config["client_id"], authority=config["authority"],
    client_credential=config["secret"],
    # token_cache=...  # Default cache is in memory only.
                       # You can learn how to use SerializableTokenCache from
                       # https://msal-python.rtfd.io/en/latest/#msal.SerializableTokenCache
    )

app = ConfidentialClientApplicationBuilder.Create(config.ClientId)
           .WithClientSecret(config.ClientSecret)
           .WithAuthority(new Uri(config.Authority))
           .Build();

The Authority is a concatenation of the cloud instance and the tenant ID, for example https://login.microsoftonline.com/contoso.onmicrosoft.com or https://login.microsoftonline.com/aaaabbbb-0000-cccc-1111-dddd2222eeee. In the appsettings.json file shown in the Configuration file section, instance and tenant are represented by the Instance and Tenant values, respectively.

In the code sample the previous snippet was taken from, Authority is a property on the AuthenticationConfig class, and is defined as such:

/// <summary>
/// URL of the authority
/// </summary>
public string Authority
{
    get
    {
        return String.Format(CultureInfo.InvariantCulture, Instance, Tenant);
    }
}

Instantiate the confidential client application with a client certificate

Here's the code to build an application with a certificate:

The code itself is exactly the same. The certificate is described in the configuration. There are many ways to get the certificate. For details see https://aka.ms/ms-id-web-certificates. Here's how you would do to get your certificate from KeyVault. Microsoft identity delegates to Azure Identity's DefaultAzureCredential, and used Managed identity when available to access the certificate from KeyVault. You can debug your application locally as it then uses your developer credentials.

  "ClientCredentials": [
      {
        "SourceType": "KeyVault",
        "KeyVaultUrl": "https://yourKeyVaultUrl.vault.azure.net",
        "KeyVaultCertificateName": "NameOfYourCertificate"
      }

In MSAL Java, there are two builders to instantiate the confidential client application with certificates:


InputStream pkcs12Certificate = ... ; /* Containing PCKS12-formatted certificate*/
string certificatePassword = ... ;    /* Contains the password to access the certificate */

IClientCredential credential = ClientCredentialFactory.createFromCertificate(pkcs12Certificate, certificatePassword);

ConfidentialClientApplication cca =
        ConfidentialClientApplication
                .builder(CLIENT_ID, credential)
                .authority(AUTHORITY)
                .build();

PrivateKey key = getPrivateKey(); /* RSA private key to sign the assertion */
X509Certificate publicCertificate = getPublicCertificate(); /* x509 public certificate used as a thumbprint */

IClientCredential credential = ClientCredentialFactory.createFromCertificate(key, publicCertificate);

ConfidentialClientApplication cca =
        ConfidentialClientApplication
                .builder(CLIENT_ID, credential)
                .authority(AUTHORITY)
                .build();


const config = {
    auth: {
        clientId: process.env.CLIENT_ID,
        authority: process.env.AAD_ENDPOINT + process.env.TENANT_ID,
        clientCertificate: {
            thumbprint:  process.env.CERTIFICATE_THUMBPRINT, // a 40-digit hexadecimal string
            privateKey:  process.env.CERTIFICATE_PRIVATE_KEY,
        }
    }
};

// Create an MSAL application object
const cca = new msal.ConfidentialClientApplication(config);

For details, see Use certificate credentials with MSAL Node.

# Pass the parameters.json file as an argument to this Python script. E.g.: python your_py_file.py parameters.json
config = json.load(open(sys.argv[1]))

# Create a preferably long-lived app instance that maintains a token cache.
app = msal.ConfidentialClientApplication(
    config["client_id"], authority=config["authority"],
    client_credential={"thumbprint": config["thumbprint"], "private_key": open(config['private_key_file']).read()},
    # token_cache=...  # Default cache is in memory only.
                       # You can learn how to use SerializableTokenCache from
                       # https://msal-python.rtfd.io/en/latest/#msal.SerializableTokenCache
    )

X509Certificate2 certificate = ReadCertificate(config.CertificateName);
app = ConfidentialClientApplicationBuilder.Create(config.ClientId)
    .WithCertificate(certificate)
    .WithAuthority(new Uri(config.Authority))
    .Build();

Advanced scenario: Instantiate the confidential client application with client assertions

In addition to using a client secret or certificate, confidential client applications can also prove their identity by using client assertions. See CredentialDescription for details.

IClientCredential credential = ClientCredentialFactory.createFromClientAssertion(assertion);

ConfidentialClientApplication cca =
        ConfidentialClientApplication
                .builder(CLIENT_ID, credential)
                .authority(AUTHORITY)
                .build();

const clientConfig = {
    auth: {
        clientId: process.env.CLIENT_ID,
        authority: process.env.AAD_ENDPOINT + process.env.TENANT_ID,
        clientAssertion:  process.env.CLIENT_ASSERTION
    }
};
const cca = new msal.ConfidentialClientApplication(clientConfig);

For details, see Initialize the ConfidentialClientApplication object.

In MSAL Python, you can provide client claims by using the claims that will be signed by this ConfidentialClientApplication's private key.

# Pass the parameters.json file as an argument to this Python script. E.g.: python your_py_file.py parameters.json
config = json.load(open(sys.argv[1]))

# Create a preferably long-lived app instance that maintains a token cache.
app = msal.ConfidentialClientApplication(
    config["client_id"], authority=config["authority"],
    client_credential={"thumbprint": config["thumbprint"], "private_key": open(config['private_key_file']).read()},
    client_claims = {"client_ip": "x.x.x.x"}
    # token_cache=...  # Default cache is in memory only.
                       # You can learn how to use SerializableTokenCache from
                       # https://msal-python.rtfd.io/en/latest/#msal.SerializableTokenCache
    )

For details, see the MSAL Python reference documentation for ConfidentialClientApplication.

Instead of a client secret or a certificate, the confidential client application can also prove its identity by using client assertions.

MSAL.NET has two methods to provide signed assertions to the confidential client app:

.WithClientAssertion()
.WithClientClaims()

When you use WithClientAssertion, provide a signed JWT. This advanced scenario is detailed in Client assertions.

string signedClientAssertion = ComputeAssertion();
app = ConfidentialClientApplicationBuilder.Create(config.ClientId)
                                          .WithClientAssertion(signedClientAssertion)
                                          .Build();

When you use WithClientClaims, MSAL.NET produces a signed assertion that contains the claims expected by Microsoft Entra ID, plus additional client claims that you want to send. This code shows how to do that:

string ipAddress = "192.168.1.2";
var claims = new Dictionary<string, string> { { "client_ip", ipAddress } };
X509Certificate2 certificate = ReadCertificate(config.CertificateName);
app = ConfidentialClientApplicationBuilder.Create(config.ClientId)
                                          .WithAuthority(new Uri(config.Authority))
                                          .WithClientClaims(certificate, claims)
                                          .Build();

Again, for details, see Client assertions.

Next steps

Move on to the next article in this scenario, Acquire a token for the app.

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