Apache Beam is a very welcoming and collaborative community, and there are lots of opportunities to contribute, both code and non-code. You can, for example:
- ask or answer questions on firstname.lastname@example.org or stackoverflow
- review proposed design ideas on email@example.com
- improve the documentation
- file bug reports
- test releases
- review changes
- write new examples
- improve your favorite language SDK (Java, Python, Go, etc)
- improve specific runners (Apache Flink, Apache Spark, Google Cloud Dataflow, etc)
- improve or add IO connectors
- add new transform libraries (statistics, ML, image processing, etc)
- work on the core programming model (read more about what a Beam pipeline is and how it runs here in Documentation)
- improve the developer experience (for example, Windows guides)
- add answers to the contribution FAQ
- organize local meetups of users or contributors to Apache Beam
Below is a tutorial for contributing code to Beam, covering our tools and typical process in detail.
Connect with the Beam community
- Consider subscribing to the firstname.lastname@example.org mailing list, especially if you plan to make more than one change or the change will be large. All decisions are consensus-based and happen on the public mailing list.
- (Optionally) Join the #beam channel of the ASF Slack.
Accounts and Permissions
Beam Wiki Space: Anyone has read access. If you wish to contribute changes, please create an account and request edit access on the email@example.com mailing list (include your Wiki account user ID).
Pull requests can only be merged by a Beam committer.
All communication is expected to align with the Code of Conduct.
Discussion about contributing code to Beam happens on the firstname.lastname@example.org mailing list. Introduce yourself!
Questions can be asked on the #beam channel of the ASF Slack. Introduce yourself!
Before You Begin
- A GitHub account.
- A Linux, macOS, or Microsoft Windows development environment.
- Java JDK 8 installed.
- Docker installed for some tasks including building worker containers and testing changes to this website locally.
- For SDK Development:
- Go 1.16.0 or later installed for Go SDK development.
- Python 3.x interpreters. You will need Python interpreters for all Python versions supported by Beam.
Interpreters should be installed and available in shell via
python3.xcommands. For more information, see: Python installation tips in Developer Wiki.
- For large contributions, a signed Individual Contributor License. Agreement (ICLA) to the Apache Software Foundation (ASF).
Share Your Intent
- Find or create an issue in the Beam repo. Tracking your work in an issue will avoid duplicated or conflicting work, and provide a place for notes. Later, your pull request will be linked to the issue as well.
- Comment “.take-issue” on the issue. This will cause the issue to be assigned to you. When you’ve completed the issue, you can close it by commenting “.close-issue”. If you are a committer and would like to assign an issue to a non-committer, they must comment on the issue first; please tag the user asking them to do so or to comment “`.take-issue`”. The command will be ignored if it is surrounded by ``` markdown characters.
- If your change is large or it is your first change, it is a good idea to discuss it on the email@example.com mailing list.
- For large changes create a design doc (template, examples) and email it to the firstname.lastname@example.org mailing list.
Setup Your Environment
You have two options for configuring your development environment:
- Manually installing the prerequisites.
- Using the automated script for Linux and macOS.
- Container-based: using a Docker image.
Local: Debian-based Distribution
To install these in a Debian-based distribution:
sudo apt-get install \ openjdk-8-jdk \ python-setuptools \ python-pip \ virtualenv \ tox \ docker-ce
- On some systems, like Ubuntu 20.04, install these:
pip3 install grpcio-tools mypy-protobuf
- If you develop in GO:
- Install Go.
- Check BEAM repo is in:
- At the end, it should look like this:
- Once Go is installed, install goavro:
$ export GOPATH=`pwd`/sdks/go/examples/.gogradle/project_gopath $ go get github.com/linkedin/goavro
Important: gLinux users should configure their machines for sudoless Docker.
Automated script for Linux and macOS
You can install these in a Debian-based distribution for Linux or macOs using the local-env-setup.sh script, which is part of the Beam repo. It contains:
- pip3 packages
- go packages
- JDK 8
To install execute:
Alternatively, you can use the Docker based local development environment to wrap your clone of the Beam repo into a container meeting the requirements above.
You can start this container using the start-build-env.sh script which is part of the Beam repo.
Check Git workflow tips if you need help with git forking, cloning, branching, committing, pull requests, and squashing commits.
Make a fork of https://github.com/apache/beam repo.
Clone the forked repository. You can download it anywhere you like.
$ mkdir -p ~/path/to/your/folder $ cd ~/path/to/your/folder $ git clone https://github.com/forked/apache/beam $ cd beam
For Go development:
We recommend putting it in your
$HOME/goby default on Unix systems).
Clone the repo, and update your branch as normal:
$ git clone https://github.com/apache/beam.git $ cd beam $ git remote add <GitHub_user> email@example.com:<GitHub_user>/beam.git $ git fetch --all
Get or Update all the Go SDK dependencies:
$ go get -u ./...
Check the environment was set up correctly.
Option 1: validate the Go, Java, and Python environments:
Important: Make sure you have activated Python development.
Option 2: Run independent checks:
- For Go development:
export GOLANG_PROTOBUF_REGISTRATION_CONFLICT=ignore./gradlew :sdks:go:examples:wordCount
- For Python development:
- For Java development:
Familiarize yourself with gradle and the project structure.
At the root of the git repository, run:
$ ./gradlew projects
Examine the available tasks in a project. For the default set of tasks, use:
$ ./gradlew tasks
For a given module, use:
$ ./gradlew -p sdks/java/io/cassandra tasks
For an exhaustive list of tasks, use:
$ ./gradlew tasks --all
Make sure you can build and run tests.
Since Beam is a large project, usually, you will want to limit testing to the particular module you are working on. Gradle will build just the necessary things to run those tests. For example:
$ ./gradlew -p sdks/go check $ ./gradlew -p sdks/java/io/cassandra check $ ./gradlew -p runners/flink check
Now you may want to set up your preferred IDE and other aspects of your development environment. See the Developers’ wiki for tips, guides, and FAQs on:
Create a Pull Request
Make your code change. Every source file needs to include the Apache license header. Every new dependency needs to have an open source license compatible with Apache.
Add unit tests for your change.
Use descriptive commit messages that make it easy to identify changes and provide a clear history.
When your change is ready to be reviewed and merged, create a pull request.
Link to the issue you are addressing in your pull request.
The pull request and any changes pushed to it will trigger pre-commit jobs. If a test fails and appears unrelated to your change, you can cause tests to be re-run by adding a single line comment on your PR:
retest this please
Pull request template has a link to a catalog of trigger phrases that start various post-commit tests suites. Use these sparingly because post-commit tests consume shared development resources.
Review Process and Releases
- Pull requests can only be merged by a Beam committer. To find a committer for your area, either:
- look in the OWNERS file of the directory where you changed files, or
- look for similar code merges, or
- ask on firstname.lastname@example.org
R: @username in the pull request to notify a reviewer.
- If you don’t get any response in 3 business days, email the email@example.com mailing list to ask for someone to look at your pull request.
Make the Reviewer’s Job Easier
Provide context for your changes in the associated issue and/or PR description.
Avoid huge mega-changes.
Review feedback typically leads to follow-up changes. It is easier to review follow-up changes when they are added as additional “fixup” commits to the existing PR/branch. This allows reviewer(s) to track the incremental progress and focus on new changes, and keeps comment threads attached to the code. Please refrain from squashing new commits into reviewed commits before review is completed. Because squashing reviewed and unreviewed commits often makes it harder to see the difference between the review iterations, reviewers may ask you to unsquash new changes.
After review is complete and the PR is accepted, fixup commits should be squashed (see Git workflow tips). Beam committers can squash all commits in the PR during merge, however if a PR has a mixture of independent changes that should not be squashed, and fixup commits, then the PR author should help squashing fixup commits to maintain a clean commit history.
Apache Beam Releases
Apache Beam makes minor releases every 6 weeks. Apache Beam has a calendar for cutting the next release branch. Your change needs to be checked into master before the release branch is cut to make the next release.
Stale Pull Requests
The community will close stale pull requests in order to keep the project healthy. A pull request becomes stale after its author fails to respond to actionable comments for 60 days. Author of a closed pull request is welcome to reopen the same pull request again in the future.
If you didn’t find the information you were looking for in this guide, please reach out to the Beam community.
Find Efforts to Contribute to
A great way to contribute is to join an existing effort. If you want to get involved but don’t have a project in mind, check our list of open starter tasks. For the most intensive efforts, check out the roadmap.
Please see Beam developers’ Wiki Contributor FAQ for more information.
If you are contributing a
PTransform to Beam, we have an extensive PTransform Style Guide.
If you are contributing a Runner to Beam, refer to the Runner authoring guide.
Review design documents.
You can also find out more information on the Beam developers’ Wiki.
Last updated on 2022/07/27
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