Authenticate Azure Services Securely

Azure Identity SDK for Python

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

Installation

pip install 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>

DefaultAzureCredential

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

from azure.identity import DefaultAzureCredential
from azure.storage.blob import BlobServiceClient

### Works in local dev AND production without code changes
credential = DefaultAzureCredential()

client = BlobServiceClient(
    account_url="https://<account>.blob.core.windows.net",
    credential=credential
)

Credential Chain Order

Order	Credential	Environment
1	EnvironmentCredential	CI/CD, containers
2	WorkloadIdentityCredential	Kubernetes
3	ManagedIdentityCredential	Azure VMs, App Service, Functions
4	SharedTokenCacheCredential	Windows only
5	VisualStudioCodeCredential	VS Code with Azure extension
6	AzureCliCredential	az login
7	AzurePowerShellCredential	Connect-AzAccount
8	AzureDeveloperCliCredential	azd auth login

Customizing DefaultAzureCredential

### Exclude credentials you don't need
credential = DefaultAzureCredential(
    exclude_environment_credential=True,
    exclude_shared_token_cache_credential=True,
    managed_identity_client_id="<user-assigned-mi-client-id>"  # For user-assigned MI
)

### Enable interactive browser (disabled by default)
credential = DefaultAzureCredential(
    exclude_interactive_browser_credential=False
)

Specific Credential Types

ManagedIdentityCredential

For Azure-hosted resources (VMs, App Service, Functions, AKS):

from azure.identity import ManagedIdentityCredential

### System-assigned managed identity
credential = ManagedIdentityCredential()

### User-assigned managed identity
credential = ManagedIdentityCredential(
    client_id="<user-assigned-mi-client-id>"
)

ClientSecretCredential

For service principal with secret:

from azure.identity import ClientSecretCredential

credential = ClientSecretCredential(
    tenant_id=os.environ["AZURE_TENANT_ID"],
    client_id=os.environ["AZURE_CLIENT_ID"],
    client_secret=os.environ["AZURE_CLIENT_SECRET"]
)

AzureCliCredential

Uses the account from az login:

from azure.identity import AzureCliCredential

credential = AzureCliCredential()

ChainedTokenCredential

Custom credential chain:

from azure.identity import (
    ChainedTokenCredential,
    ManagedIdentityCredential,
    AzureCliCredential
)

### Try managed identity first, fall back to CLI
credential = ChainedTokenCredential(
    ManagedIdentityCredential(client_id="<user-assigned-mi-client-id>"),
    AzureCliCredential()
)

Credential Types Table

Credential	Use Case	Auth Method
DefaultAzureCredential	Most scenarios	Auto-detect
ManagedIdentityCredential	Azure-hosted apps	Managed Identity
ClientSecretCredential	Service principal	Client secret
ClientCertificateCredential	Service principal	Certificate
AzureCliCredential	Local development	Azure CLI
AzureDeveloperCliCredential	Local development	Azure Developer CLI
InteractiveBrowserCredential	User sign-in	Browser OAuth
DeviceCodeCredential	Headless/SSH	Device code flow

Getting Tokens Directly

from azure.identity import DefaultAzureCredential

credential = DefaultAzureCredential()

### Get token for a specific scope
token = credential.get_token("https://management.azure.com/.default")
print(f"Token expires: {token.expires_on}")

### For Azure Database for PostgreSQL
token = credential.get_token("https://ossrdbms-aad.database.windows.net/.default")

Async Client

from azure.identity.aio import DefaultAzureCredential
from azure.storage.blob.aio import BlobServiceClient

async def main():
    credential = DefaultAzureCredential()
    
    async with BlobServiceClient(
        account_url="https://<account>.blob.core.windows.net",
        credential=credential
    ) as client:
        # ... async operations
        pass
    
    await credential.close()

Best Practices

1. Use DefaultAzureCredential for code that runs locally and in Azure
2. Never hardcode credentials - use environment variables or managed identity
3. Prefer managed identity in production Azure deployments
4. Use ChainedTokenCredential when you need a custom credential order
5. Close async credentials explicitly or use context managers
6. Set AZURE_CLIENT_ID for user-assigned managed identities
7. Exclude unused credentials to speed up authentication

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.