[sentry-junior]

backend / backend migration tests spends about 237s on master CI building test_region, test_control and test_secondary. The first test's setup runs every migration from scratch.

With this change:

• On master, after the tests pass, the job saves a pg_dump of the three test databases plus a manifest of the migration files it was built from. The cache key hashes src/**/migrations/*.py and src/sentry/new_migrations/**.
• Every run restores the exact key, or the newest master dump through restore-keys, before running pytest. The job already uses --reuse-db, so pytest-django keeps the restored databases and applies only the migrations added since the dump.
• If the manifest lists a migration file this checkout doesn't have, the script skips the restore and pytest builds the databases from scratch as it does today. That happens when a PR branch is behind the master commit that saved the dump.
• .github/file-filters.yml: changes to the new script now trigger the migration tests.

Local measurements (single migration test, --migrations --reuse-db)

• From scratch: 306s DB setup
• After restoring a dump (~6s): ~40s DB setup; the test passes
• I also checked that a manifest with an unknown migration skips the restore, and that a missing cache falls through to a normal build.

Not verified yet

• No cache exists until this lands, so this PR's own run takes the "no saved databases" path. The first master run saves the dump, and the run after that is the first real restore in CI.
• I didn't check the case where the dump is behind and pytest applies the newer migrations on top. That path is plain pytest-django keepdb plus migrate.

via @joshuarli.

--

View Junior Session [Sentry]

[github-actions]

🚨 Warning: This pull request contains Frontend and Backend changes!

It's discouraged to make changes to Sentry's Frontend and Backend in a single pull request. The Frontend and Backend are not atomically deployed. If the changes are interdependent of each other, they must be separated into two pull requests and be made forward or backwards compatible, such that the Backend or Frontend can be safely deployed independently.

Have questions? Please ask in the #discuss-dev-infra channel.

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