[PSA] LogDiff in Sheriff-o-Matic
Sean McCullough
If you don’t sheriff the Chromium tree with Sheriff-o-Matic, you can stop reading.
TL;DR: In sheriff-o-matic you can now click on “Δ” links next to a failing builder, and get visual diffs of failing logs against passing logs. Long sections of common lines are collapsed by default.
Clicking here:
Gives you:
We’ve observed sheriffs manually eye-grepping through log files to identify lines that are unexpected and may explain the cause of a failure. Locating and loading log files for latest passing and failing builds, then manually comparing them line by line is a form of toil we felt we could automate.
We’ve implemented this simple heuristic so that alerts can now highlight unexpected lines in failing build logs (and show what the corresponding line looked like in the most recent passing build) all in a single page directly accessible from the alert itself. The latest passing build lines are green, and latest failing build lines are red.
This project was completed over the summer by our intern, Renjie Tang. We have some ideas to improve it (mostly around filtering out irrelevant diffs like tmp dirs and timestamps), but would love to hear feedback about how useful (or not) it is in its current form.