<!--IssueSummary start--> <details> <summary> Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards. </summary> - [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=27817) </details> <!--IssueSummary end--> ### Problem to solve Currently, if a request fails to complete due to a timeout or resource exhaustion, we just show a 500 error which doesn't give the user any context on what went wrong. It would be great if we can provide more detail to the user so that they can quickly take appropriate action instead of wasting time trying to figure out a generic error message. ### Intended users - Customers - Developers - Support engineers ### Further details Consider these logs: ```plaintext 2019-03-22_14:44:16.12097 time="2019-03-22T14:44:16Z" level=info msg="finished streaming call with code Canceled" error="rpc error: code = Canceled desc = rpc error: code = Unavailable desc = CommitDiff: send: rpc error: code = Canceled desc = context canceled" grpc.code=Canceled grpc.meta.auth_version=v2 grpc.meta.client_name=gitlab-web grpc.method=CommitDiff grpc.request.deadline="2019-03-22T14:44:16Z" grpc.request.fullMethod=/gitaly.DiffService/CommitDiff grpc.request.glRepository=project-1 grpc.request.repoPath=group/project.git grpc.request.repoStorage=default grpc.request.topLevelGroup=smart-assurance grpc.service=gitaly.DiffService grpc.start_time="2019-03-22T14:43:16Z" grpc.time_ms=60025.1 peer.address=@ span.kind=server system=grpc ``` This log is from a failed request for creating a merge request for a huge changeset. Instead of simply throwing a 500 error, we could perhaps also say why the request timed out. ### Proposal Add more details to error messages. ### Links / references - https://gitlab.zendesk.com/agent/tickets/117200 - https://gitlab.zendesk.com/agent/tickets/447124 (similar error, but related to `DiffStats` as well as `CommitDiff` ; internal logs in [Sentry](https://sentry.gitlab.net/gitlab/gitlabcom/issues/4181621/?query=correlation_id%3A01H9Q6GZ51HGWMBVVEXR2PNFES) & [ES](https://log.gprd.gitlab.net/app/r/s/BcqwV))