ClientAssertionCredential Class

Authenticates a service principal with a JWT assertion.

This credential is for advanced scenarios. CertificateCredential has a more convenient API for the most common assertion scenario, authenticating a service principal with a certificate.

Inheritance

azure.identity._internal.get_token_mixin.GetTokenMixin

ClientAssertionCredential

Constructor

ClientAssertionCredential(tenant_id: str, client_id: str, func: Callable[[], str], **kwargs: Any)

Parameters

Name	Description
tenant_id Required	str ID of the principal's tenant. Also called its "directory" ID.
client_id Required	str The principal's client ID
func Required	A callable that returns a string assertion. The credential will call this every time it acquires a new token.

Keyword-Only Parameters

Name	Description
authority	str Authority of a Microsoft Entra endpoint, for example "login.microsoftonline.com", the authority for Azure Public Cloud (which is the default). AzureAuthorityHosts defines authorities for other clouds.
additionally_allowed_tenants	List[str] Specifies tenants in addition to the specified "tenant_id" for which the credential may acquire tokens. Add the wildcard value "*" to allow the credential to acquire tokens for any tenant the application can access.

Examples

Create a ClientAssertionCredential.

   from azure.identity import ClientAssertionCredential

   def get_assertion():
       return "<client-assertion>"

   credential = ClientAssertionCredential(
       tenant_id="<tenant_id>",
       client_id="<client_id>",
       func=get_assertion,
   )

Methods

close
get_token	Request an access token for scopes. This method is called automatically by Azure SDK clients.

close

close() -> None

get_token

Request an access token for scopes.

This method is called automatically by Azure SDK clients.

get_token(*scopes: str, claims: str | None = None, tenant_id: str | None = None, enable_cae: bool = False, **kwargs: Any) -> AccessToken

Parameters

Name	Description
scopes Required	str desired scopes for the access token. This method requires at least one scope. For more information about scopes, see https://learn.microsoft.com/entra/identity-platform/scopes-oidc.

Keyword-Only Parameters

Name	Description
claims	str additional claims required in the token, such as those returned in a resource provider's claims challenge following an authorization failure.
tenant_id	str optional tenant to include in the token request.
enable_cae	bool indicates whether to enable Continuous Access Evaluation (CAE) for the requested token. Defaults to False.

Returns

Type	Description
AccessToken	An access token with the desired scopes.

Exceptions

Type	Description
CredentialUnavailableError	the credential is unable to attempt authentication because it lacks required data, state, or platform support
ClientAuthenticationError	authentication failed. The error's message attribute gives a reason.