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Airflow Breeze Logo

Airflow Breeze CI Environment

Airflow Breeze is an easy-to-use integration test environment managed via Docker Compose. The environment is available for local use and is also integrated into Airflow's CI Travis tests.

We called it Airflow Breeze as It's a Breeze to develop Airflow.

The advantages and disadvantages of using the Breeze environment vs. other ways of testing Airflow are described in CONTRIBUTING.rst.

Here is a short 10-minute video about Airflow Breeze:

Airflow Breeze Simplified Development Workflow

Prerequisites

Docker Community Edition

  • Version: Install the latest stable Docker Community Edition and add it to the PATH.
  • Permissions: Configure to run the docker commands directly and not only via root user. Your user should be in the docker group. See Docker installation guide for details.
  • Disk space: On macOS, increase your available disk space before starting to work with the environment. At least 128 GB of free disk space is recommended. You can also get by with a smaller space but make sure to clean up the Docker disk space periodically. See also Docker for Mac - Space for details on increasing disk space available for Docker on Mac.
  • Docker problems: Sometimes it is not obvious that space is an issue when you run into a problem with Docker. If you see a weird behaviour, try cleaning up the images. Also see pruning instructions from Docker.

Docker Compose

  • Version: Install the latest stable Docker Compose and add it to the PATH. See Docker Compose Installation Guide for details.
  • Permissions: Configure to run the docker-compose command.

Docker Images Used by Breeze

For all development tasks, related integration tests and static code checks, we use the CI image maintained on the Docker Hub in the apache/airflow repository. This Docker image contains a lot test-related packages (size of ~1GB). Its tag follows the pattern of <BRANCH>-python<PYTHON_VERSION>-ci (for example, apache/airflow:master-python3.6-ci). The image is built using the Dockerfile Dockerfile.

Before you run tests, enter the environment or run local static checks, the necessary local images should be pulled and built from Docker Hub. This happens automatically for the test environment but you need to manually trigger it for static checks as described in Building the images and Pulling the latest images. The static checks will fail and inform what to do if the image is not yet built.

Building the image first time pulls a pre-built version of images from the Docker Hub, which may take some time. But for subsequent source code changes, no wait time is expected. However, changes to sensitive files like setup.py or Dockerfile will trigger a rebuild that may take more time though it is highly optimized to only rebuild what is needed.

In most cases, rebuilding an image requires network connectivity (for example, to download new dependencies). If you work offline and do not want to rebuild the images when needed, you can set the FORCE_ANSWER_TO_QUESTIONS variable to no as described in the Default behaviour for user interaction section.

See Troubleshooting section for steps you can make to clean the environment.

Getopt and gstat

  • For Linux, run apt install util-linux coreutils or an equivalent if your system is not Debian-based.

  • For macOS, install GNU getopt and gstat utilities to get Airflow Breeze running.

    Run brew install gnu-getopt coreutils and then follow instructions to link the gnu-getopt version to become the first on the PATH. Make sure to re-login after you make the suggested changes.

Examples:

If you use bash, run this command and re-login:

echo 'export PATH="/usr/local/opt/gnu-getopt/bin:$PATH"' >> ~/.bash_profile
. ~/.bash_profile

If you use zsh, run this command and re-login:

echo 'export PATH="/usr/local/opt/gnu-getopt/bin:$PATH"' >> ~/.zprofile
. ~/.zprofile

Memory

Minimum 4GB RAM is required to run the full Breeze environment.

On macOS, 2GB of RAM are available for your Docker containers by default, but more memory is recommended (4GB should be comfortable). For details see Docker for Mac - Advanced tab.

Airflow Directory Structure inside Docker

When you are in the container, the following directories are used:

/opt/airflow - Contains sources of Airflow mounted from the host (AIRFLOW_SOURCES).
/root/airflow - Contains all the "dynamic" Airflow files (AIRFLOW_HOME), such as:
    airflow.db - sqlite database in case sqlite is used;
    dags - folder with non-test dags (test dags are in /opt/airflow/tests/dags);
    logs - logs from Airflow executions;
    unittest.cfg - unit test configuration generated when entering the environment;
    webserver_config.py - webserver configuration generated when running Airflow in the container.

Note that when running in your local environment, the /root/airflow/logs folder is actually mounted from your logs directory in the Airflow sources, so all logs created in the container are automatically visible in the host as well. Every time you enter the container, the logs directory is cleaned so that logs do not accumulate.

Using the Airflow Breeze Environment

Airflow Breeze is a bash script serving as a "swiss-army-knife" of Airflow testing. Under the hood it uses other scripts that you can also run manually if you have problem with running the Breeze environment.

Breeze script allows performing the following tasks:

  • Enter an interactive environment when no command flags are specified (default behaviour).
  • Stop the interactive environment with -k, --stop-environment command.
  • Build a Docker image with -b, --build-only command.
  • Set up autocomplete for itself with -a, --setup-autocomplete command.
  • Build documentation with -O, --build-docs command.
  • Run static checks either for currently staged change or for all files with -S, --static-check or -F, --static-check-all-files commands.
  • Set up local virtualenv with -e, --setup-virtualenv command.
  • Run a test target specified with -t, --test-target command.
  • Execute an arbitrary command in the test environment with -x, --execute-command command.
  • Execute an arbitrary docker-compose command with -d, --docker-compose command.

Entering Breeze

You enter the Breeze integration test environment by running the ./breeze script. You can run it with the --help option to see the list of available flags. See Airflow Breeze flags for details.

./breeze

First time you run Breeze, it pulls and builds a local version of Docker images. It pulls the latest Airflow CI images from Airflow DockerHub and use them to build your local Docker images. Note that the first run (per python) might take up to 10 minutes on a fast connection to start. Subsequent runs should be much faster.

Once you enter the environment, you are dropped into bash shell of the Airflow container and you can run tests immediately.

You can set up autocomplete for commands and add the checked-out Airflow repository to your PATH to run Breeze without the ./ and from any directory.

Stopping Breeze

After starting up, the environment runs in the background and takes precious memory. You can always stop it via:

./breeze --stop-environment

Choosing a Breeze Environment

You can use additional breeze flags to customize your environment. For example, you can specify a Python version to use, backend and a container environment for testing. With Breeze, you can recreate the same environments as we have in matrix builds in Travis CI.

For example, you can choose to run Python 3.6 tests with MySQL as backend and in the Docker environment as follows:

./breeze --python 3.6 --backend mysql --env docker

The choices you make are persisted in the ./.build/ cache directory so that next time when you use the breeze script, it could use the values that were used previously. This way you do not have to specify them when you run the script. You can delete the .build/ directory in case you want to restore the default settings.

The defaults when you run the Breeze environment are Python 3.6, Sqlite, and Docker.

Available Docker Environments

You can choose a container environment when you run Breeze with --env flag. Running the default docker environment takes a considerable amount of resources. You can run a slimmed-down version of the environment - just the Apache Airflow container - by choosing bare environment instead.

The following environments are available:

  • The docker environment (default): starts all dependencies required by a full integration test suite (Postgres, Mysql, Celery, etc). This option is resource intensive so do not forget to [stop environment](#stopping-the-environment) when you are finished. This option is also RAM intensive and can slow down your machine.
  • The kubernetes environment: Runs Airflow tests within a Kubernetes cluster.
  • The bare environment: runs Airflow in the Docker without any external dependencies. It only works for independent tests. You can only run it with the sqlite backend.

Cleaning Up the Environment

You may need to clean up your Docker environment occasionally. The images are quite big (1.5GB for both images needed for static code analysis and CI tests) and, if you often rebuild/update them, you may end up with some unused image data.

To clean up the Docker environment:

  1. Stop Breeze with ./breeze --stop-environment.

  2. Run the docker system prune command.

  3. Run docker images --all and docker ps --all to verify that your Docker is clean.

    Both commands should return an empty list of images and containers respectively.

If you run into disk space errors, consider pruning your Docker images with the docker system prune --all command. You may need to restart the Docker Engine before running this command.

In case of disk space errors on macOS, increase the disk space available for Docker. See Prerequisites for details.

Building the Images

You can manually trigger building the local images using the script:

./scripts/ci/local_ci_build.sh

The scripts that build the images are optimized to minimize the time needed to rebuild the image when the source code of Airflow evolves. This means that if you already have the image locally downloaded and built, the scripts will determine whether the rebuild is needed in the first place. Then the scripts will make sure that minimal number of steps are executed to rebuild parts of the image (for example, PIP dependencies) and will give you an image consistent with the one used during Continuous Integration.

Pulling the Latest Images

Sometimes the image on the Docker Hub needs to be rebuilt from scratch. This is required, for example, when there is a security update of the Python version that all the images are based on. In this case it is usually faster to pull the latest images rather than rebuild them from scratch.

You can do it via the --force-pull-images flag to force pulling the latest images from the Docker Hub.

To manually force pulling the images for static checks, use the script:

./scripts/ci/local_ci_pull_and_build.sh

In the future Breeze will warn you when you are recommended to pull images.

Running Arbitrary Commands in the Breeze Environment

To run other commands/executables inside the Breeze Docker-based environment, use the -x, --execute-command flag. To add arguments, specify them together with the command surrounded with either " or ', or pass them after -- as extra arguments.

./breeze --execute-command "ls -la"
./breeze --execute-command ls -- --la

Running Docker Compose Commands

To run Docker Compose commands (such as help, pull, etc), use the -d, --docker-compose flag. To add extra arguments, specify them after -- as extra arguments.

./breeze --docker-compose pull -- --ignore-pull-failures

Mounting Local Sources to Breeze

Important sources of Airflow are mounted inside the airflow-testing container that you enter. This means that you can continue editing your changes on the host in your favourite IDE and have them visible in the Docker immediately and ready to test without rebuilding images. You can disable mounting by specifying --skip-mounting-source-volume flag when running Breeze. In this case you will have sources embedded in the container and changes to these sources will not be persistent.

After you run Breeze for the first time, you will have an empty directory files in your source code, which will be mapped to /files in your Docker container. You can pass there any files you need to configure and run Docker. They will not be removed between Docker runs.

Adding/Modifying Dependencies

If you need to change apt dependencies in the Dockerfile, add Python packages in setup.py or add javascript dependencies in package.json, you can either add dependencies temporarily for a single Breeze session or permanently in setup.py, Dockerfile, or package.json files.

Installing Dependencies for a Single Breeze Session

You can install dependencies inside the container using sudo apt install, pip install or yarn install (in airflow/www folder) respectively. This is useful if you want to test something quickly while you are in the container. However, these changes are not retained: they disappear once you exit the container (except for theh node.js dependencies if your sources are mounted to the container). Therefore, if you want to retain a new dependency, follow the second option described below.

Adding Dependencies Permanently

You can add dependencies to the Dockerfile, setup.py or package.json and rebuild the image. This should happen automatically if you modify any of these files. After you exit the container and re-run breeze, Breeze detects changes in dependencies, asks you to confirm rebuilding the image and proceeds with rebuilding if you confirm (or skip it if you do not confirm). After rebuilding is done, Breeze drops you to shell. You may also provide the --build-only flag to only rebuild images and not to go into shell.

Changing apt Dependencies in the Dockerfile

During development, changing dependencies in apt-get closer to the top of the Dockerfile invalidates cache for most of the image. It takes long time for Breeze to rebuild the image. So, it is a recommended practice to add new dependencies initially closer to the end of the Dockerfile. This way dependencies will be added incrementally.

Before merge, these dependencies should be moved to the appropriate apt-get install command, which is already in the Dockerfile.

Port Forwarding

When you run Airflow Breeze, the following ports are automatically forwarded:

  • 28080 -> forwarded to Airflow webserver -> airflow-testing:8080
  • 25433 -> forwarded to Postgres database -> postgres:5432
  • 23306 -> forwarded to MySQL database -> mysql:3306

You can connect to these ports/databases using:

  • Webserver: http://127.0.0.1:28080
  • Postgres: jdbc:postgresql://127.0.0.1:25433/airflow?user=postgres&password=airflow
  • Mysql: jdbc:mysql://localhost:23306/airflow?user=root

Start the webserver manually with the airflow webserver command if you want to connect to the webserver. You can use tmux to multiply terminals.

For databases, you need to run airflow db reset at least once (or run some tests) after you started Airflow Breeze to get the database/tables created. You can connect to databases with IDE or any other database client:

Database view

You can change the used host port numbers by setting appropriate environment variables:

  • WEBSERVER_HOST_PORT
  • POSTGRES_HOST_PORT
  • MYSQL_HOST_PORT

If you set these variables, next time when you enter the environment the new ports should be in effect.

Setting Up Autocompletion

The breeze command comes with a built-in bash/zsh autocomplete option for its flags. When you start typing the command, you can use <TAB> to show all the available switches and get autocompletion on typical values of parameters that you can use.

You can set up the autocomplete option automatically by running:

./breeze --setup-autocomplete

You get the autocompletion working when you re-enter the shell.

Zsh autocompletion is currently limited to only autocomplete flags. Bash autocompletion also completes flag values (for example, Python version or static check name).

Setting Defaults for User Interaction

Sometimes during the build, you are asked whether to perform an action, skip it, or quit. This happens when rebuilding or removing an image - actions that take a lot of time and could be potentially destructive.

For automation scripts, you can export one of the three variables to control the default interaction behaviour:

export FORCE_ANSWER_TO_QUESTIONS="yes"

If FORCE_ANSWER_TO_QUESTIONS is set to yes, the images are automatically rebuilt when needed. Images are deleted without asking.

export FORCE_ANSWER_TO_QUESTIONS="no"

If FORCE_ANSWER_TO_QUESTIONS is set to no, the old images are used even if rebuilding is needed. This is useful when you work offline. Deleting images is aborted.

export FORCE_ANSWER_TO_QUESTIONS="quit"

If FORCE_ANSWER_TO_QUESTIONS is set to quit, the whole script is aborted. Deleting images is aborted.

If more than one variable is set, yes takes precedence over no, which takes precedence over quit.

Building the Documentation

To build documentation in Breeze, use the -O, --build-docs command:

./breeze --build-docs

Results of the build can be found in the docs/_build folder.

Often errors during documentation generation come from the docstrings of auto-api generated classes. During the docs building auto-api generated files are stored in the docs/_api folder. This helps you easily identify the location the problems with documentation originated from.

Using Your Host IDE

You can set up your host IDE (for example, IntelliJ's PyCharm/Idea) to work with Breeze and benefit from all the features provided by your IDE, such as local and remote debugging, autocompletion, documentation support, etc.

To use your host IDE with Breeze:

  1. Create a local virtual environment as follows:

    mkvirtualenv <ENV_NAME> --python=python<VERSION>

    You can use any of the following wrappers to create and manage your virtual environemnts: pyenv, pyenv-virtualenv, or virtualenvwrapper.

    Ideally, you should have virtualenvs for all Python versions supported by Airflow (3.5, 3.6, 3.7) and switch between them with the workon command.

  2. Use the workon command to enter the Breeze environment.

  3. Initialize the created local virtualenv:

    ./breeze --initialize-local-virtualenv

  4. Select the virtualenv you created as the project's default virtualenv in your IDE.

Note that you can also use the local virtualenv for Airflow development without Breeze. This is a lightweight solution that has its own limitations.

More details on using the local virtualenv are avaiable in the LOCAL_VIRTUALENV.rst.

Running static checks in Breeze

The Breeze environment is also used to run some of the static checks as described in STATIC_CODE_CHECKS.rst.

Running Tests in Breeze

As soon as you enter the Breeze environment, you can run Airflow unit tests via the run-tests command.

For supported CI test suites, types of unit tests, and other tests, see TESTING.rst.

Breeze Command-Line Interface Reference

Airflow Breeze Syntax

This is the current syntax for ./breeze:

 Usage: breeze [FLAGS] \
   [-k]|[-S <STATIC_CHECK>]|[-F <STATIC_CHECK>]|[-O]|[-e]|[-a]|[-b]|[-t <TARGET>]|[-x <COMMAND>]|[-d <COMMAND>] \
   -- <EXTRA_ARGS>

 The swiss-knife-army tool for Airflow testings. It allows to perform various test tasks:

   * Enter interactive environment when no command flags are specified (default behaviour)
   * Stop the interactive environment with -k, --stop-environment command
   * Run static checks - either for currently staged change or for all files with
     -S, --static-check or -F, --static-check-all-files commanbd
   * Build documentation with -O, --build-docs command
   * Setup local virtualenv with -e, --setup-virtualenv command
   * Setup autocomplete for itself with -a, --setup-autocomplete command
   * Build docker image with -b, --build-only command
   * Run test target specified with -t, --test-target connad
   * Execute arbitrary command in the test environmenrt with -x, --execute-command command
   * Execute arbitrary docker-compose command with -d, --docker-compose command

 ** Commands

   By default the script enters IT environment and drops you to bash shell,
   but you can also choose one of the commands to run specific actions instead:

 -k, --stop-environment
         Bring down running docker compose environment. When you start the environment, the docker
         containers will continue running so that startup time is shorter. But they take quite a lot of
         memory and CPU. This command stops all running containers from the environment.

 -O, --build-docs
        Build documentation.

 -S, --static-check <STATIC_CHECK>
         Run selected static checks for currently changed files. You should specify static check that
         you would like to run or 'all' to run all checks. One of
         [ all all-but-pylint check-apache-license check-executables-have-shebangs check-hooks-apply check-merge-conflict check-xml debug-statements doctoc detect-private-key end-of-file-fixer flake8 forbid-tabs insert-license lint-dockerfile mixed-line-ending mypy pylint pylint-test setup-order shellcheck].
         You can pass extra arguments including options to to the pre-commit framework as
         <EXTRA_ARGS> passed after --. For example:

         './breeze  --static-check mypy' or
         './breeze  --static-check mypy -- --files tests/core.py'

         You can see all the options by adding --help EXTRA_ARG:

         './breeze  --static-check mypy -- --help'

 -F, --static-check-all-files <STATIC_CHECK>
         Run selected static checks for all applicable files. You should specify static check that
         you would like to run or 'all' to run all checks. One of
         [ all all-but-pylint check-apache-license check-executables-have-shebangs check-hooks-apply check-merge-conflict check-xml debug-statements doctoc detect-private-key end-of-file-fixer flake8 forbid-tabs insert-license lint-dockerfile mixed-line-ending mypy pylint pylint-test setup-order shellcheck].
         You can pass extra arguments including options to the pre-commit framework as
         <EXTRA_ARGS> passed after --. For example:

         './breeze --static-check-all-files mypy' or
         './breeze --static-check-all-files mypy -- --verbose'

         You can see all the options by adding --help EXTRA_ARG:

         './breeze --static-check-all-files mypy -- --help'

 -e, --initialize-local-virtualenv
         Initializes locally created virtualenv installing all dependencies of Airflow.
         This local virtualenv can be used to aid autocompletion and IDE support as
         well as run unit tests directly from the IDE. You need to have virtualenv
         activated before running this command.

 -a, --setup-autocomplete
         Sets up autocomplete for breeze commands. Once you do it you need to re-enter the bash
         shell and when typing breeze command <TAB> will provide autocomplete for parameters and values.

 -b, --build-only
         Only build docker images but do not enter the airflow-testing docker container.

 -t, --test-target <TARGET>
         Run the specified unit test target. There might be multiple
         targets specified separated with comas. The <EXTRA_ARGS> passed after -- are treated
         as additional options passed to pytest. For example:

         './breeze --test-target tests/test_core.py -- --logging-level=DEBUG'

 -x, --execute-command <COMMAND>
         Run chosen command instead of entering the environment. The command is run using
         'bash -c "<command with args>" if you need to pass arguments to your command, you need
         to pass them together with command surrounded with " or '. Alternatively you can pass arguments as
          <EXTRA_ARGS> passed after --. For example:

         './breeze --execute-command "ls -la"' or
         './breeze --execute-command ls -- --la'

 -d, --docker-compose <COMMAND>
         Run docker-compose command instead of entering the environment. Use 'help' command
         to see available commands. The <EXTRA_ARGS> passed after -- are treated
         as additional options passed to docker-compose. For example

         './breeze --docker-compose pull -- --ignore-pull-failures'

 ** General flags

 -h, --help
         Shows this help message.

 -P, --python <PYTHON_VERSION>
         Python version used for the image. This is always major/minor version.
         One of [ 3.6 3.7 ]. Default is the python3 or python on the path.

 -E, --env <ENVIRONMENT>
         Environment to use for tests. It determines which types of tests can be run.
         One of [ docker kubernetes ]. Default: docker

 -B, --backend <BACKEND>
         Backend to use for tests - it determines which database is used.
         One of [ sqlite mysql postgres ]. Default: sqlite

 -K, --kubernetes-version <KUBERNETES_VERSION>
         Kubernetes version - only used in case of 'kubernetes' environment.
         One of [ v1.13.0 ]. Default: v1.13.0

 -M, --kubernetes-mode <KUBERNETES_MODE>
         Kubernetes mode - only used in case of 'kubernetes' environment.
         One of [ persistent_mode git_mode ]. Default: git_mode

 -s, --skip-mounting-source-volume
         Skips mounting local volume with sources - you get exactly what is in the
         docker image rather than your current local sources of airflow.

 -v, --verbose
         Show verbose information about executed commands (enabled by default for running test)

 -y, --assume-yes
         Assume 'yes' answer to all questions.

 -n, --assume-no
         Assume 'no' answer to all questions.

 -C, --toggle-suppress-cheatsheet
         Toggles on/off cheatsheet displayed before starting bash shell

 -A, --toggle-suppress-asciiart
         Toggles on/off asciiart displayed before starting bash shell

 ** Dockerfile management flags

 -D, --dockerhub-user
         DockerHub user used to pull, push and build images. Default: apache.

 -H, --dockerhub-repo
         DockerHub repository used to pull, push, build images. Default: airflow.

 -r, --force-build-images
         Forces building of the local docker images. The images are rebuilt
         automatically for the first time or when changes are detected in
         package-related files, but you can force it using this flag.

 -R, --force-build-images-clean
         Force build images without cache. This will remove the pulled or build images
         and start building images from scratch. This might take a long time.

 -p, --force-pull-images
         Forces pulling of images from DockerHub before building to populate cache. The
         images are pulled by default only for the first time you run the
         environment, later the locally build images are used as cache.

 -u, --push-images
         After building - uploads the images to DockerHub
         It is useful in case you use your own DockerHub user to store images and you want
         to build them locally. Note that you need to use 'docker login' before you upload images.

 -c, --cleanup-images
         Cleanup your local docker cache of the airflow docker images. This will not reclaim space in
         docker cache. You need to 'docker system prune' (optionally with --all) to reclaim that space.


.. END BREEZE HELP MARKER

Convenience Scripts

Once you run ./breeze you can also execute various actions via generated convenience scripts:

Enter the environment          : ./.build/cmd_run
Run command in the environment : ./.build/cmd_run "[command with args]" [bash options]
Run tests in the environment   : ./.build/test_run [test-target] [pytest options]
Run Docker compose command     : ./.build/dc [help/pull/...] [docker-compose options]

Troubleshooting

If you are having problems with the Breeze environment, try the steps below. After each step you can check whether your problem is fixed.

  1. If you are on macOS, check if you have enough disk space for Docker.
  2. Stop Breeze with ./breeze --stop-environment.
  3. Delete the .build directory and run ./breeze --force-pull-images.
  4. Clean up Docker images.
  5. Restart your Docker Engine and try again.
  6. Restart your machine and try again.
  7. Re-install Docker CE and try again.

In case the problems are not solved, you can set the VERBOSE variable to "true" (export VERBOSE="true"), rerun the failed command, copy-and-paste the output from your terminal to the Airflow Slack #troubleshooting channel and add the problem description.

Fixing File/Directory Ownership

On Linux there is a problem with propagating ownership of created files (a known Docker problem). Basically, files and directories created in the container are not owned by the host user (but by the root user in our case). This may prevent you from switching branches, for example, if files owned by the root user are created within your sources. In case you are on a Linux host and have some files in your sources created y the root user, you can fix the ownership of those files by running this script:

./scripts/ci/local_ci_fix_ownership.sh