fix: add actionable errors for GCE long running operations

Author: parthea

google/api_core/exceptions.py

@@ -142,10 +142,19 @@ def __init__(self, message, errors=(), details=(), response=None, error_info=Non
         self._error_info = error_info
 
     def __str__(self):
+        error_msg = "{} {}".format(self.code, self.message)
         if self.details:
-            return "{} {} {}".format(self.code, self.message, self.details)
+            error_msg = f"{error_msg} {self.details}"
         else:
-            return "{} {}".format(self.code, self.message)
+            if self.errors:
+                errors = [
+                    f"{error.code}: {error.message}"
+                    for error in self.errors
+                    if hasattr(error, "code") and hasattr(error, "message")
+                ]
+                if len(errors) > 0:
+                    error_msg.append("\n".join(errors))
+        return error_msg
 
     @property
     def reason(self):

google/api_core/extended_operation.py

@@ -158,10 +158,14 @@ def _handle_refreshed_operation(self):
                 return
 
             if self.error_code and self.error_message:
+                errors = []
+                if hasattr(self, "error") and hasattr(self.error, "errors"):
+                    errors = self.error.errors
                 exception = exceptions.from_http_status(
                     status_code=self.error_code,
                     message=self.error_message,
                     response=self._extended_operation,
+                    errors=errors,
                 )
                 self.set_exception(exception)
             elif self.error_code or self.error_message: