- Install prek:
uv tool install prek - Enable commit hooks:
prek install - Never run pytest, python, or airflow commands directly on the host — always use
breeze. - Place temporary scripts in
dev/(mounted as/opt/airflow/dev/inside Breeze).
<PROJECT> is folder where pyproject.toml of the package you want to test is located. For example, airflow-core or providers/amazon.
<target_branch> is the branch the PR will be merged into — usually main, but could be v3-1-test when creating a PR for the 3.1 branch.
- Run a single test:
uv run --project <PROJECT> pytest path/to/test.py::TestClass::test_method -xvs - Run a test file:
uv run --project <PROJECT> pytest path/to/test.py -xvs - Run all tests in package:
uv run --project <PROJECT> pytest path/to/package -xvs - If uv tests fail with missing system dependencies, run the tests with breeze:
breeze run pytest <tests> -xvs - Run a Python script:
uv run --project <PROJECT> python dev/my_script.py - Run core or provider tests suite in parallel:
breeze testing <test_group> --run-in-parallel(test groups:core-tests,providers-tests) - Run core or provider db tests suite in parallel:
breeze testing <test_group> --run-db-tests-only --run-in-parallel(test groups:core-tests,providers-tests) - Run core or provider non-db tests suite in parallel:
breeze testing <test_group> --skip-db-tests --use-xdist(test groups:core-tests,providers-tests) - Run single provider complete test suite:
breeze testing providers-tests --test-type "Providers[PROVIDERS_LIST]"(e.g.,Providers[google]orProviders[amazon]or "Providers[amazon,google]") - Run Helm tests in parallel with xdist
breeze testing helm-tests --use-xdist - Run Helm tests with specific K8s version:
breeze testing helm-tests --use-xdist --kubernetes-version 1.35.0 - Run specific Helm test type:
breeze testing helm-tests --use-xdist --test-type <type>(types:airflow_aux,airflow_core,apiserver,dagprocessor,other,redis,security,statsd,webserver) - Run other suites of tests
breeze testing <test_group>(test groups:airflow-ctl-tests,docker-compose-tests,task-sdk-tests - Run Airflow CLI:
breeze run airflow dags list - Type-check:
breeze run mypy path/to/code - Lint with ruff only:
prek run ruff --from-ref <target_branch> - Format with ruff only:
prek run ruff-format --from-ref <target_branch> - Run regular (fast) static checks:
prek run --from-ref <target_branch> --stage pre-commit - Run manual (slower) checks:
prek run --from-ref <target_branch> --stage manual - Build docs:
breeze build-docs - Determine which tests to run based on changed files:
breeze selective-checks --commit-ref <commit_with_squashed_changes>
SQLite is the default backend. Use --backend postgres or --backend mysql for integration tests that need those databases. If Docker networking fails, run docker network prune.
UV workspace monorepo. Key paths:
airflow-core/src/airflow/— core scheduler, API, CLI, modelsmodels/— SQLAlchemy models (DagModel, TaskInstance, DagRun, Asset, etc.)jobs/— scheduler, triggerer, Dag processor runnersapi_fastapi/core_api/— public REST API v2, UI endpointsapi_fastapi/execution_api/— task execution communication APIdag_processing/— Dag parsing and validationcli/— command-line interfaceui/— React/TypeScript web interface (Vite)
task-sdk/— lightweight SDK for Dag authoring and task execution runtimesrc/airflow/sdk/execution_time/— task runner, supervisor
providers/— 100+ provider packages, each with its ownpyproject.tomlairflow-ctl/— management CLI toolchart/— Helm chart for Kubernetes deployment
- Users author Dags with the Task SDK (
airflow.sdk). - Dag Processor parses Dag files in isolated processes and stores serialized Dags in the metadata DB.
- Scheduler reads serialized Dags — never runs user code — and creates Dag runs / task instances.
- Workers execute tasks via Task SDK and communicate with the API server through the Execution API — never access the metadata DB directly.
- API Server serves the React UI and handles all client-database interactions.
- Triggerer evaluates deferred tasks/sensors in isolated processes.
- No
assertin production code. time.monotonic()for durations, nottime.time().- In
airflow-core, functions with asessionparameter must not callsession.commit(). Use keyword-onlysessionparameters. - Imports at top of file. Valid exceptions: circular imports, lazy loading for worker isolation,
TYPE_CHECKINGblocks. - Guard heavy type-only imports (e.g.,
kubernetes.client) withTYPE_CHECKINGin multi-process code paths. - Apache License header on all new files (prek enforces this).
- Add tests for new behavior — cover success, failure, and edge cases.
- Use pytest patterns, not
unittest.TestCase. - Use
spec/autospecwhen mocking. - Use
time_machinefor time-dependent tests. - Use
@pytest.mark.parametrizefor multiple similar inputs. - Use
@pytest.mark.db_testfor tests that require database access. - Test fixtures:
devel-common/src/tests_common/pytest_plugin.py. - Test location mirrors source:
airflow/cli/cli_parser.py→tests/cli/test_cli_parser.py.
Write commit messages focused on user impact, not implementation details.
- Good:
Fix airflow dags test command failure without serialized Dags - Good:
UI: Fix Grid view not refreshing after task actions - Bad:
Initialize DAG bundles in CLI get_dag function
Add a newsfragment for user-visible changes:
echo "Brief description" > airflow-core/newsfragments/{PR_NUMBER}.{bugfix|feature|improvement|doc|misc|significant}.rst
Always push to the user's fork, not to the upstream apache/airflow repo. Never push
directly to main.
Before pushing, determine the fork remote. Check git remote -v — if origin does not
point to apache/airflow, use origin (it's the user's fork). If origin points to
apache/airflow, look for another remote that points to the user's fork. If no fork remote
exists, create one:
gh repo fork apache/airflow --remote --remote-name forkBefore pushing, perform a self-review of your changes following the Gen-AI review guidelines
in contributing-docs/05_pull_requests.rst and the
code review checklist in .github/instructions/code-review.instructions.md:
- Review the full diff (
git diff main...HEAD) and verify every change is intentional and related to the task — remove any unrelated changes. - Read
.github/instructions/code-review.instructions.mdand check your diff against every rule — architecture boundaries, database correctness, code quality, testing requirements, API correctness, and AI-generated code signals. Fix any violations before pushing. - Confirm the code follows the project's coding standards and architecture boundaries described in this file.
- Run regular (fast) static checks (
prek run --from-ref <target_branch> --stage pre-commit) and fix any failures. - Run manual (slower) checks (
prek run --from-ref <target_branch> --stage manual) and fix any failures. - Run relevant individual tests and confirm they pass.
- Find which tests to run for the changes with selective-checks and run those tests in parallel to confirm they pass and check for CI-specific issues.
- Check for security issues — no secrets, no injection vulnerabilities, no unsafe patterns.
Then push the branch to the fork remote and open the PR creation page in the browser with the body pre-filled (including the generative AI disclosure already checked):
git push -u <fork-remote> <branch-name>
gh pr create --web --title "Short title (under 70 chars)" --body "$(cat <<'EOF'
Brief description of the changes.
closes: #ISSUE (if applicable)
---
##### Was generative AI tooling used to co-author this PR?
- [X] Yes — <Agent Name and Version>
Generated-by: <Agent Name and Version> following [the guidelines](https://github.com/apache/airflow/blob/main/contributing-docs/05_pull_requests.rst#gen-ai-assisted-contributions)
EOF
)"The --web flag opens the browser so the user can review and submit. The --body flag
pre-fills the PR template with the generative AI disclosure already completed.
Remind the user to:
- Review the PR title — keep it short (under 70 chars) and focused on user impact.
- Add a brief description of the changes at the top of the body.
- Reference related issues when applicable (
closes: #ISSUEorrelated: #ISSUE).
- Ask first
- Large cross-package refactors.
- New dependencies with broad impact.
- Destructive data or migration changes.
- Never
- Commit secrets, credentials, or tokens.
- Edit generated files by hand when a generation workflow exists.
- Use destructive git operations unless explicitly requested.