gnomon GitHub Action | Gnomon Docs

A branch of your database per pull request. Migrations and tests run against the branch; the PR gets a comment with the schema and data changes; the branch is dropped when the PR closes. Main is never touched until someone merges the branch (gnomon merge pr-<n>), which brings the schema changes and then the data.

on:
  pull_request:
    types: [opened, synchronize, reopened, closed]
jobs:
  db:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - id: branch
        uses: bitsinfra/gnomon/action@v1.0.1
        with:
          database-url: ${{ secrets.STAGING_DATABASE_URL }}
          migrations: db/migrations/*.sql      # optional: DDL on the branch only (gnomon migrate)
      - if: github.event.action != 'closed'
        run: npm test
        env:
          DATABASE_URL: ${{ steps.branch.outputs.database-url }}
      - if: github.event.action != 'closed'
        uses: bitsinfra/gnomon/action@v1.0.1
        with:
          database-url: ${{ secrets.STAGING_DATABASE_URL }}
          mode: comment

Inputs: database-url (required), branch (default pr-<number>), parent (default main), mode (auto, create, comment, drop), c-module (true when the server loads the C module, so the branch setting alone routes), migrations (files run on the branch with gnomon migrate before its URL is computed), github-token, gnomon-version (a released CLI, or source).

Outputs: branch, database-url (sessions start on the branch; masked in logs), options.

Notes:

In SQL-only mode the URL carries options=-c gnomon.branch=... -c search_path=gnomon_r_.... Tools that qualify table names (Prisma, PostgREST) need the C module or the routing schema (see integrations/).
Schema changes: pass the migration files as migrations. DDL goes through gnomon.ddl and stays on the branch (a schema version), the rest runs on the branch, all in one transaction, and the URL then names the version's views. Additions, constraints, renames, drops and type changes are supported; the run fails on anything a branch cannot change, naming the operation (docs/schema-changes.md). Migration tools that run their own DDL over their own connection need their script output fed to migrations instead (prisma migrate diff --script, alembic upgrade --sql).
action/test.sh runs the action's script against a local database.