azure-identity-dotnet

CategoryGeneral
AuthorAgentic Awesome Skills 社区
LicenseMIT
Rating4.70/5
Uses5.1K

Azure.Identity (.NET)

Authentication library for Azure SDK clients using Microsoft Entra ID (formerly Azure AD).

Installation

bash
dotnet add package Azure.Identity

For ASP.NET Core

dotnet add package Microsoft.Extensions.Azure

For brokered authentication (Windows)

dotnet add package Azure.Identity.Broker

Current Versions: Stable v1.17.1, Preview v1.18.0-beta.2

Environment Variables

Service Principal with Secret

bash
AZURE_CLIENT_ID=<application-client-id>
AZURE_TENANT_ID=<directory-tenant-id>
AZURE_CLIENT_SECRET=<client-secret-value>

Service Principal with Certificate

bash
AZURE_CLIENT_ID=<application-client-id>
AZURE_TENANT_ID=<directory-tenant-id>
AZURE_CLIENT_CERTIFICATE_PATH=<path-to-pfx-or-pem>
AZURE_CLIENT_CERTIFICATE_PASSWORD=<certificate-password>  # Optional

Managed Identity

bash
AZURE_CLIENT_ID=<user-assigned-managed-identity-client-id>  # Only for user-assigned

DefaultAzureCredential

The recommended credential for most scenarios. Tries multiple authentication methods in order:

| Order | Credential | Enabled by Default |
|-------|------------|-------------------|
| 1 | EnvironmentCredential | Yes |
| 2 | WorkloadIdentityCredential | Yes |
| 3 | ManagedIdentityCredential | Yes |
| 4 | VisualStudioCredential | Yes |
| 5 | VisualStudioCodeCredential | Yes |
| 6 | AzureCliCredential | Yes |
| 7 | AzurePowerShellCredential | Yes |
| 8 | AzureDeveloperCliCredential | Yes |
| 9 | InteractiveBrowserCredential | No |

Basic Usage

csharp
using Azure.Identity;
using Azure.Storage.Blobs;

var credential = new DefaultAzureCredential();
var blobClient = new BlobServiceClient(
new Uri("https://myaccount.blob.core.windows.net"),
credential);

ASP.NET Core with Dependency Injection

csharp
using Azure.Identity;
using Microsoft.Extensions.Azure;

builder.Services.AddAzureClients(clientBuilder =>
{
clientBuilder.AddBlobServiceClient(
new Uri("https://myaccount.blob.core.windows.net"));
clientBuilder.AddSecretClient(
new Uri("https://myvault.vault.azure.net"));

// Uses DefaultAzureCredential by default
clientBuilder.UseCredential(new DefaultAzureCredential());
});

Customizing DefaultAzureCredential

csharp
var credential = new DefaultAzureCredential(
    new DefaultAzureCredentialOptions
    {
        ExcludeEnvironmentCredential = true,
        ExcludeManagedIdentityCredential = false,
        ExcludeVisualStudioCredential = false,
        ExcludeAzureCliCredential = false,
        ExcludeInteractiveBrowserCredential = false, // Enable interactive
        TenantId = "<tenant-id>",
        ManagedIdentityClientId = "<user-assigned-mi-client-id>"
    });

Credential Types

ManagedIdentityCredential (Production)

csharp
// System-assigned managed identity
var credential = new ManagedIdentityCredential(ManagedIdentityId.SystemAssigned);

// User-assigned by client ID
var credential = new ManagedIdentityCredential(
ManagedIdentityId.FromUserAssignedClientId("<client-id>"));

// User-assigned by resource ID
var credential = new ManagedIdentityCredential(
ManagedIdentityId.FromUserAssignedResourceId("<resource-id>"));

ClientSecretCredential

csharp
var credential = new ClientSecretCredential(
    tenantId: "<tenant-id>",
    clientId: "<client-id>",
    clientSecret: "<client-secret>");

var client = new SecretClient(
new Uri("https://myvault.vault.azure.net"),
credential);

ClientCertificateCredential

csharp
var certificate = X509CertificateLoader.LoadCertificateFromFile("MyCertificate.pfx");
var credential = new ClientCertificateCredential(
    tenantId: "<tenant-id>",
    clientId: "<client-id>",
    certificate);

ChainedTokenCredential (Custom Chain)

csharp
var credential = new ChainedTokenCredential(
    new ManagedIdentityCredential(),
    new AzureCliCredential());

var client = new SecretClient(
new Uri("https://myvault.vault.azure.net"),
credential);

Developer Credentials

csharp
// Azure CLI
var credential = new AzureCliCredential();

// Azure PowerShell
var credential = new AzurePowerShellCredential();

// Azure Developer CLI (azd)
var credential = new AzureDeveloperCliCredential();

// Visual Studio
var credential = new VisualStudioCredential();

// Interactive Browser
var credential = new InteractiveBrowserCredential();

Environment-Based Configuration

csharp
// Production vs Development
TokenCredential credential = builder.Environment.IsProduction()
    ? new ManagedIdentityCredential("<client-id>")
    : new DefaultAzureCredential();

Sovereign Clouds

csharp
var credential = new DefaultAzureCredential(
    new DefaultAzureCredentialOptions
    {
        AuthorityHost = AzureAuthorityHosts.AzureGovernment
    });

// Available authority hosts:
// AzureAuthorityHosts.AzurePublicCloud (default)
// AzureAuthorityHosts.AzureGovernment
// AzureAuthorityHosts.AzureChina
// AzureAuthorityHosts.AzureGermany

Credential Types Reference

| Category | Credential | Purpose |
|----------|------------|---------|
| Chains | DefaultAzureCredential | Preconfigured chain for dev-to-prod |
| | ChainedTokenCredential | Custom credential chain |
| Azure-Hosted | ManagedIdentityCredential | Azure managed identity |
| | WorkloadIdentityCredential | Kubernetes workload identity |
| | EnvironmentCredential | Environment variables |
| Service Principal | ClientSecretCredential | Client ID + secret |
| | ClientCertificateCredential | Client ID + certificate |
| | ClientAssertionCredential | Signed client assertion |
| User | InteractiveBrowserCredential | Browser-based auth |
| | DeviceCodeCredential | Device code flow |
| | OnBehalfOfCredential | Delegated identity |
| Developer | AzureCliCredential | Azure CLI |
| | AzurePowerShellCredential | Azure PowerShell |
| | AzureDeveloperCliCredential | Azure Developer CLI |
| | VisualStudioCredential | Visual Studio |

Best Practices

1. Use Deterministic Credentials in Production

csharp
// Development
var devCredential = new DefaultAzureCredential();

// Production - use specific credential
var prodCredential = new ManagedIdentityCredential("<client-id>");

2. Reuse Credential Instances

csharp
// Good: Single credential instance shared across clients
var credential = new DefaultAzureCredential();
var blobClient = new BlobServiceClient(blobUri, credential);
var secretClient = new SecretClient(vaultUri, credential);

3. Configure Retry Policies

csharp
var options = new ManagedIdentityCredentialOptions(
    ManagedIdentityId.FromUserAssignedClientId(clientId))
{
    Retry =
    {
        MaxRetries = 3,
        Delay = TimeSpan.FromSeconds(0.5),
    }
};
var credential = new ManagedIdentityCredential(options);

4. Enable Logging for Debugging

csharp
using Azure.Core.Diagnostics;

using AzureEventSourceListener listener = new((args, message) =>
{
if (args is { EventSource.Name: "Azure-Identity" })
{
Console.WriteLine(message);
}
}, EventLevel.LogAlways);

Error Handling

csharp
using Azure.Identity;
using Azure.Security.KeyVault.Secrets;

var client = new SecretClient(
new Uri("https://myvault.vault.azure.net"),
new DefaultAzureCredential());

try
{
KeyVaultSecret secret = await client.GetSecretAsync("secret1");
}
catch (AuthenticationFailedException e)
{
Console.WriteLine($"Authentication Failed: {e.Message}");
}
catch (CredentialUnavailableException e)
{
Console.WriteLine($"Credential Unavailable: {e.Message}");
}

Key Exceptions

| Exception | Description |
|-----------|-------------|
| AuthenticationFailedException | Base exception for authentication errors |
| CredentialUnavailableException | Credential cannot authenticate in current environment |
| AuthenticationRequiredException | Interactive authentication is required |

Managed Identity Support

Supported Azure services:

  • Azure App Service and Azure Functions

  • Azure Arc

  • Azure Cloud Shell

  • Azure Kubernetes Service (AKS)

  • Azure Service Fabric

  • Azure Virtual Machines

  • Azure Virtual Machine Scale Sets

Thread Safety

All credential implementations are thread-safe. A single credential instance can be safely shared across multiple clients and threads.

Related SDKs

| SDK | Purpose | Install |
|-----|---------|---------|
| Azure.Identity | Authentication (this SDK) | dotnet add package Azure.Identity |
| Microsoft.Extensions.Azure | DI integration | dotnet add package Microsoft.Extensions.Azure |
| Azure.Identity.Broker | Brokered auth (Windows) | dotnet add package Azure.Identity.Broker |

Reference Links

| Resource | URL |
|----------|-----|
| NuGet Package | https://www.nuget.org/packages/Azure.Identity |
| API Reference | https://learn.microsoft.com/dotnet/api/azure.identity |
| Credential Chains | https://learn.microsoft.com/dotnet/azure/sdk/authentication/credential-chains |
| Best Practices | https://learn.microsoft.com/dotnet/azure/sdk/authentication/best-practices |
| GitHub Source | https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/identity/Azure.Identity |

When to Use

This skill is applicable to execute the workflow or actions described in the overview.

Limitations

  • Use this skill only when the task clearly matches the scope described above.
  • Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
  • Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.
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