An unfiltered branch trigger is a budget incident waiting to happen.

Six trigger types exist — push, pull request, tag, manual, webhook, Pub/Sub — and filtering push triggers is the cheap fix.

A trigger fired on push to any branch. A contractor pushed 40 commits to an experimental branch in one afternoon — 40 full builds burned the monthly Cloud Build budget in a day and pushed 40 untagged images into the shared registry.

fix: one line

gcloud builds triggers create github \
  --branch-pattern="^main$"  # reserve PR triggers for feature branches