[Identity] Loosen imds unreachable error check (Azure#33928)

Signed-off-by: Paul Van Eck <paulvaneck@microsoft.com>

Author: pvaneck

sdk/identity/azure-identity/CHANGELOG.md

@@ -9,6 +9,7 @@
 ### Bugs Fixed
 
 - Fixed the bug that `ClientAssertionCredential` constructor fails if kwargs are provided. ([#33673](https://github.com/Azure/azure-sdk-for-python/issues/33673))
+- `ManagedIdentityCredential` is more lenient with the error message it matches when falling through to the next credential in the chain in the case that Docker Desktop returns a 403 response when attempting to access the IMDS endpoint. ([#33928](https://github.com/Azure/azure-sdk-for-python/pull/33928))
 
 ### Other Changes
 

sdk/identity/azure-identity/azure/identity/_credentials/imds.py

@@ -43,13 +43,13 @@ def _check_forbidden_response(ex: HttpResponseError) -> None:
     """Special case handling for Docker Desktop.
 
     Docker Desktop proxies all HTTP traffic, and if the IMDS endpoint is unreachable, it
-    responds with a 403 with a message that contains "A socket operation was attempted to an unreachable network".
+    responds with a 403 with a message that contains "unreachable".
 
     :param ~azure.core.exceptions.HttpResponseError ex: The exception raised by the request
     :raises ~azure.core.exceptions.CredentialUnavailableError: When the IMDS endpoint is unreachable
     """
     if ex.status_code == 403:
-        if ex.message and "A socket operation was attempted to an unreachable network" in ex.message:
+        if ex.message and "unreachable" in ex.message:
             error_message = f"ManagedIdentityCredential authentication unavailable. Error: {ex.message}"
             raise CredentialUnavailableError(message=error_message) from ex
 

sdk/identity/azure-identity/tests/test_imds_credential.py

@@ -65,12 +65,13 @@ def send(request, **kwargs):
         assert error_message in ex.value.message
 
 
-def test_imds_request_failure_docker_desktop():
+@pytest.mark.parametrize("error_ending", ("network", "host", "foo"))
+def test_imds_request_failure_docker_desktop(error_ending):
     """The credential should raise CredentialUnavailableError when a 403 with a specific message is received"""
 
     error_message = (
         "connecting to 169.254.169.254:80: connecting to 169.254.169.254:80: dial tcp 169.254.169.254:80: "
-        "connectex: A socket operation was attempted to an unreachable network."  # cspell:disable-line
+        f"connectex: A socket operation was attempted to an unreachable {error_ending}."  # cspell:disable-line
     )
     probe = mock_response(status_code=403, json_payload={"error": error_message})
     transport = mock.Mock(send=mock.Mock(return_value=probe))

sdk/identity/azure-identity/tests/test_imds_credential_async.py

@@ -98,12 +98,13 @@ async def send(request, **kwargs):
         assert error_message in ex.value.message
 
 
-async def test_imds_request_failure_docker_desktop():
+@pytest.mark.parametrize("error_ending", ("network", "host", "foo"))
+async def test_imds_request_failure_docker_desktop(error_ending):
     """The credential should raise CredentialUnavailableError when a 403 with a specific message is received"""
 
     error_message = (
         "connecting to 169.254.169.254:80: connecting to 169.254.169.254:80: dial tcp 169.254.169.254:80: "
-        "connectex: A socket operation was attempted to an unreachable network."  # cspell:disable-line
+        f"connectex: A socket operation was attempted to an unreachable {error_ending}."  # cspell:disable-line
     )
     probe = mock_response(status_code=403, json_payload={"error": error_message})
     transport = mock.Mock(send=mock.Mock(return_value=get_completed_future(probe)))