task-debugger

Setup

Taskcluster CLI:

taskcluster version  # check if installed
export TASKCLUSTER_ROOT_URL=https://firefox-ci-tc.services.mozilla.com

If not installed: https://github.com/taskcluster/taskcluster/releases/latest/

Commands:

• •taskcluster task log <task-id> - Get logs
• •taskcluster task def <task-id> - Get definition (optional)

Debug Process

1. •Extract task ID from message or URL
2. •Fetch logs: taskcluster task log <task-id>
3. •Analyze errors (tracebacks, test failures, build errors)
4. •If fix is obvious → apply it. Otherwise → reproduce locally:
   • •Docker-worker tasks: taskgraph load-task --develop <task-id> (Firefox: ./mach taskgraph, others: check virtualenv or uv run taskgraph)
   • •Flags: --interactive, --volume, --root, --image, --keep
   • •Non-docker: extract command from task def and run locally
5. •For non-obvious issues: add debug statements → iterate → fix
6. •Verify fix using same reproduction method
7. •Clean up debug artifacts (don't re-verify after cleanup)
8. •Report: root cause, fix, verification, files changed