Google Cloud Build - View logs permissions
If you add the project viewer role then this will resolve the issue. But, it seems like this is an issue (or maybe a feature request - to add the necessary permission to the Logs Viewer so that logs outside of the Stackdriver logging page can be viewed in other UIs as well), looking at the documentation it says "roles/viewer (Project Viewer) gives members the same permissions as roles/logging.viewer at the project level. " which means that by just assigning the Logs Viewer then it should have given the user the necessary permission to view the logs at the Cloud Build UI.
Google Cloud enterprise support confirmed to me that the only role that currently grants this is the project-level Viewer permission (or Editor/Owner).
One workaround is to set the --gcs-log-dir
flag when submitting a build to a bucket you control (rather than the default Google-managed gs://[PROJECT_NUMBER].cloudbuild-logs.googleusercontent.com/
bucket).
They're tracking making a more granular permission in this feature request: https://issuetracker.google.com/issues/134928412, which you can subscribe to updates on.