Apache Airflow

Apache Airflow - A platform to programmatically author, schedule, and monitor workflows
Under Apache License 2.0
By apache

python apache hacktoberfest workflow scheduler airflow apache-airflow

Apache Airflow

Apache Airflow (or simply Airflow) is a platform to programmatically author, schedule, and monitor workflows.

When workflows are defined as code, they become more maintainable, versionable, testable, and collaborative.

Use Airflow to author workflows as directed acyclic graphs (DAGs) of tasks. The Airflow scheduler executes your tasks on an array of workers while following the specified dependencies. Rich command line utilities make performing complex surgeries on DAGs a snap. The rich user interface makes it easy to visualize pipelines running in production, monitor progress, and troubleshoot issues when needed.

Table of contents

Project Focus

Airflow works best with workflows that are mostly static and slowly changing. When the DAG structure is similar from one run to the next, it clarifies the unit of work and continuity. Other similar projects include Luigi, Oozie and Azkaban.

Airflow is commonly used to process data, but has the opinion that tasks should ideally be idempotent (i.e., results of the task will be the same, and will not create duplicated data in a destination system), and should not pass large quantities of data from one task to the next (though tasks can pass metadata using Airflow's Xcom feature). For high-volume, data-intensive tasks, a best practice is to delegate to external services specializing in that type of work.

Airflow is not a streaming solution, but it is often used to process real-time data, pulling data off streams in batches.



Apache Airflow is tested with:

| | Main version (dev) | Stable version (2.1.4) |
| -------------------- | ------------------------- | ------------------------ |
| Python | 3.6, 3.7, 3.8, 3.9 | 3.6, 3.7, 3.8, 3.9 |
| Kubernetes | 1.18, 1.19, 1.20 | 1.18, 1.19, 1.20 |
| PostgreSQL | 9.6, 10, 11, 12, 13 | 9.6, 10, 11, 12, 13 |
| MySQL | 5.7, 8 | 5.7, 8 |
| SQLite | 3.15.0+ | 3.15.0+ |
| MSSQL(Experimental) | 2019 | |

Note: MySQL 5.x versions are unable to or have limitations with
running multiple schedulers -- please see the Scheduler docs.
MariaDB is not tested/recommended.

Note: SQLite is used in Airflow tests. Do not use it in production. We recommend
using the latest stable version of SQLite for local development.

Getting started

Visit the official Airflow website documentation (latest stable release) for help with
installing Airflow,
getting started, or walking
through a more complete tutorial.

Note: If you're looking for documentation for the main branch (latest development branch): you can find it on s.apache.org/airflow-docs.

For more information on Airflow Improvement Proposals (AIPs), visit
the Airflow Wiki.

Documentation for dependent projects like provider packages, Docker image, Helm Chart, you'll find it in the documentation index.

Installing from PyPI

We publish Apache Airflow as apache-airflow package in PyPI. Installing it however might be sometimes tricky
because Airflow is a bit of both a library and application. Libraries usually keep their dependencies open, and
applications usually pin them, but we should do neither and both simultaneously. We decided to keep
our dependencies as open as possible (in setup.py) so users can install different versions of libraries
if needed. This means that pip install apache-airflow will not work from time to time or will
produce unusable Airflow installation.

To have repeatable installation, however, we keep a set of "known-to-be-working" constraint
files in the orphan constraints-main and constraints-2-0 branches. We keep those "known-to-be-working"
constraints files separately per major/minor Python version.
You can use them as constraint files when installing Airflow from PyPI. Note that you have to specify
correct Airflow tag/version/branch and Python versions in the URL.

  1. Installing just Airflow:

Note: Only pip installation is currently officially supported.

While it is possible to install Airflow with tools like Poetry or
pip-tools, they do not share the same workflow as
pip - especially when it comes to constraint vs. requirements management.
Installing via Poetry or pip-tools is not currently supported.

If you wish to install Airflow using those tools, you should use the constraint files and convert
them to the appropriate format and workflow that your tool requires.

pip install 'apache-airflow==2.1.4' \
--constraint "https://raw.githubusercontent.com/apache/airflow/constraints-2.1.4/constraints-3.7.txt"

  1. Installing with extras (i.e., postgres, google)

pip install 'apache-airflow[postgres,google]==2.1.4' \
--constraint "https://raw.githubusercontent.com/apache/airflow/constraints-2.1.4/constraints-3.7.txt"

For information on installing provider packages, check

Official source code

Apache Airflow is an Apache Software Foundation (ASF) project,
and our official source code releases:

Following the ASF rules, the source packages released must be sufficient for a user to build and test the
release provided they have access to the appropriate platform and tools.

Convenience packages

There are other ways of installing and using Airflow. Those are "convenience" methods - they are
not "official releases" as stated by the ASF Release Policy, but they can be used by the users
who do not want to build the software themselves.

Those are - in the order of most common ways people install Airflow:

All those artifacts are not official releases, but they are prepared using officially released sources.
Some of those artifacts are "development" or "pre-release" ones, and they are clearly marked as such
following the ASF Policy.

User Interface

Semantic versioning

As of Airflow 2.0.0, we support a strict SemVer approach for all packages released.

There are few specific rules that we agreed to that define details of versioning of the different

Version Life Cycle

Apache Airflow version life cycle:

| Version | Current Patch/Minor | State | First Release | Limited Support | EOL/Terminated |
| 2 | 2.1.4 | Supported | Dec 17, 2020 | Dec 31, 2021 | TBD |
| 1.10 | 1.10.15 | EOL | Aug 27, 2018 | Dec 17, 2020 | June 17, 2021 |
| 1.9 | 1.9.0 | EOL | Jan 03, 2018 | Aug 27, 2018 | Aug 27, 2018 |
| 1.8 | 1.8.2 | EOL | Mar 19, 2017 | Jan 03, 2018 | Jan 03, 2018 |
| 1.7 | | EOL | Mar 28, 2016 | Mar 19, 2017 | Mar 19, 2017 |

Limited support versions will be supported with security and critical bug fix only.
EOL versions will not get any fixes nor support.
We always recommend that all users run the latest available minor release for whatever major version is in use.
We highly recommend upgrading to the latest Airflow major release at the earliest convenient time and before the EOL date.

Support for Python and Kubernetes versions

As of Airflow 2.0, we agreed to certain rules we follow for Python and Kubernetes support.
They are based on the official release schedule of Python and Kubernetes, nicely summarized in the
Python Developer's Guide and
Kubernetes version skew policy.

  1. We drop support for Python and Kubernetes versions when they reach EOL. We drop support for those
    EOL versions in main right after EOL date, and it is effectively removed when we release the
    first new MINOR (Or MAJOR if there is no new MINOR version) of Airflow
    For example, for Python 3.6 it means that we drop support in main right after 23.12.2021, and the first
    MAJOR or MINOR version of Airflow released after will not have it.

  2. The "oldest" supported version of Python/Kubernetes is the default one. "Default" is only meaningful
    in terms of "smoke tests" in CI PRs, which are run using this default version and the default reference
    image available. Currently apache/airflow:latest and apache/airflow:2.1.4 images
    are both Python 3.6 images. However, the first MINOR/MAJOR release of Airflow release after 23.12.2021 will
    become Python 3.7 images.

  3. We support a new version of Python/Kubernetes in main after they are officially released, as soon as we
    make them work in our CI pipeline (which might not be immediate due to dependencies catching up with
    new versions of Python mostly) we release new images/support in Airflow based on the working CI setup.

Additional notes on Python version requirements


Want to help build Apache Airflow? Check out our contributing documentation.

Official Docker (container) images for Apache Airflow are described in IMAGES.rst.

Who uses Apache Airflow?

More than 400 organizations are using Apache Airflow
in the wild.

Who Maintains Apache Airflow?

Airflow is the work of the community,
but the core committers/maintainers
are responsible for reviewing and merging PRs as well as steering conversations around new feature requests.
If you would like to become a maintainer, please review the Apache Airflow
committer requirements.

Can I use the Apache Airflow logo in my presentation?

Yes! Be sure to abide by the Apache Foundation trademark policies and the Apache Airflow Brandbook. The most up to date logos are found in this repo and on the Apache Software Foundation website.

Airflow merchandise

If you would love to have Apache Airflow stickers, t-shirt, etc. then check out
Redbubble Shop.



The CI infrastructure for Apache Airflow has been sponsored by: