Authentication permission problems in Cloud Functions

Common Problems or Queries

• The Service Account corresponding to PubSub fails when trying to invoke the Cloud Function.
• Permission error when executing Cloud Functions from PubSub.
• How to grant "run invoker" permissions to a Service Account?

Solution

This problem occurs when the Service Account doesn't have the necessary permissions to invoke the Cloud Function:

Problem diagnosis:

1. Verify the Service Account:

   • Confirm which SA is trying to invoke the CF
   • Review error logs to identify the specific SA
   • Verify that the SA is correctly configured in PubSub

2. Review current permissions:

   • List current SA permissions
   • Verify permissions on the Cloud Function
   • Confirm IAM configuration

Step-by-step solution:

1. Grant "run invoker" permission:

   gcloud functions add-iam-policy-binding FUNCTION_NAME \
     --member="serviceAccount:SA_EMAIL" \
     --role="roles/cloudfunctions.invoker"

2. For Cloud Run (if applicable):

   gcloud run services add-iam-policy-binding SERVICE_NAME \
     --member="serviceAccount:SA_EMAIL" \
     --role="roles/run.invoker"

3. Verify PubSub configuration:

   • Confirm that the subscription uses the correct SA
   • Verify that the endpoint is correctly configured
   • Ensure that the SA has permissions on the topic

4. Validate the solution:

   • Execute an invocation test
   • Review logs to confirm there are no errors
   • Monitor functionality for a period

Responsible team: ANDES Resources Reference ticket: ANDES-496