Azure Identity SDK for Rust

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

Installation

cargo add azure_identity

Environment Variables

# Service Principal (for production/CI)
AZURE_TENANT_ID=<your-tenant-id>
AZURE_CLIENT_ID=<your-client-id>
AZURE_CLIENT_SECRET=<your-client-secret>

# User-assigned Managed Identity (optional)
AZURE_CLIENT_ID=<managed-identity-client-id>

DeveloperToolsCredential

The recommended credential for local development. Tries developer tools in order (Azure CLI, Azure Developer CLI):

use azure_identity::DeveloperToolsCredential;
use azure_security_keyvault_secrets::SecretClient;

let credential = DeveloperToolsCredential::new(None)?;
let client = SecretClient::new(
    "https://my-vault.vault.azure.net/",
    credential.clone(),
    None,
)?;

Credential Chain Order

Credential Types

ManagedIdentityCredential

For Azure-hosted resources:

use azure_identity::ManagedIdentityCredential;

// System-assigned managed identity
let credential = ManagedIdentityCredential::new(None)?;

// User-assigned managed identity
let options = ManagedIdentityCredentialOptions {
    client_id: Some("<user-assigned-mi-client-id>".into()),
    ..Default::default()
};
let credential = ManagedIdentityCredential::new(Some(options))?;

ClientSecretCredential

For service principal with secret:

use azure_identity::ClientSecretCredential;

let credential = ClientSecretCredential::new(
    "<tenant-id>".into(),
    "<client-id>".into(),
    "<client-secret>".into(),
    None,
)?;

Best Practices

1. Use DeveloperToolsCredential for local dev — automatically picks up Azure CLI
2. Use ManagedIdentityCredential in production — no secrets to manage
3. Clone credentials — credentials are Arc-wrapped and cheap to clone
4. Reuse credential instances — same credential can be used with multiple clients
5. Use tokio feature — cargo add azure_identity --features tokio

Reference Links