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Sheriff-o-matic only shows you things that are failing right now. It tries to group failures for you that have the same regression range and show you the most important problems at the top.

How to use

See the help page embedded in Sheriff-o-matic.

(TODO: We can deprecate this page?)


Use the menu bar on the left to pick the appropriate tree for your sheriffing role.

Snooze button

Snooze is WIP. For now it dims out the alert and moves it to the bottom of the list for an hour. This is shared amongst all sheriffs. 

Eventually we plan for it to allow you to give it a revision number at which point you believe the problem should be fixed, in which case it would be snoozed until that revision number passed (if it's still failing of course). We'll build out the feature more, based off feedback from sheriffs.

Link bug button

Associates a bug with a failure group. For now this only works with one bug; eventually this will probably work with multiple bugs. This is shared amongst all sheriffs.

Both these buttons require you to be logged in with your account.


You can configure the tool e.g. choosing the builder type to use for the links in the tool.

Where is the code?

The frontend lives on appengine. The code is at See the README in that directory for more information.

The backend is just a cron that runs in a tight loop and generates the alerts json feed that gets uploaded to and served from The code for the cron lives in the infra repo at

sheriff-o-matic is down, what do I do?

The most common failure mode for sheriff-o-matic is that the backend that generates the alerts json gets stuck. The good news is that you can run that backend locally and have it upload the json to sheriff-o-matic. So, while you're waiting for a trooper to get back to you, you can try running the backend yourself:
  1. Get an infra checkout with "fetch infra" (this is fast)
  2. cd infra
  3. git fetch origin && gclient sync
  4. while true; do time python; done
That will generate the alert json and upload it to sheriff-o-matic. sheriff-o-matic just reads that json and generates the UI from that.