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This page is meant to document the various steps to working with git to contribute or review Kafka code. There are probably a lot of bugs in these steps or possible better recipes, so help make this page better.

Simple contributor workflow

This is the simple workflow and will work well for small features development for people who don't have direct access to check in to the Apache repository. Let's assume you are working on a feature or bug called, xyz:

1. Checkout a new repository:

  git clone https://git-wip-us.apache.org/repos/asf/kafka.git kafka

Or if you already have a copy of the repository, just check for updates

  git fetch

2. Create and checkout a feature branch to work in:

  git checkout -b xyz remotes/origin/trunk

3. Do some work on this branch and periodically checkin locally:

  git commit -a

4. When done (or periodically) rebase your branch to take any changes from trunk:

  git fetch
  git rebase remotes/origin/trunk

5. Make a patch containing your work and upload it to JIRA:

  git format-patch trunk --stdout > xyz-v1.patch

6. You may need to iterate/rebase your patch a few times as people comment on the code until a commit checks it in to the main repository.

You will also want to ensure you have your username and email setup correctly so that we correctly record the source of the contribution:

git config --global user.name "Palmer Eldritch"
git config --global user.email "peldritch@layoutsinc.com"

Reviewer workflow:

This assumes you already have a copy of the repository.

1. Make sure your code is up-to-date:

  git fetch

2. Checkout the destination branch:

  git checkout trunk

3. See what the patch will do:

  git apply --stat xyz-v1.patch

4. See that the patch will apply cleanly (otherwise prod the contributor to rebase):

  git apply --check xyz-v1.patch

6. Apply the patch to trunk

  git am --signoff < xyz-v1.patch

7. If things go wrong (tests fail, you find some problem, etc), you can back out:

  git reset --hard HEAD
  git clean -f

8. Push the change back to Apache:

  git push origin trunk

Simple Commiter Workflow

If you have commit access on the apache repository then you will not be applying patches in the manner described in the reviewer workflow. Instead, once your patch has been reviewed you will check it in yourself directly from your feature branch:

1. Create a branch to work on:

    git fetch
    git checkout -b xyz remotes/origin/trunk 
  

2. Implement the feature.
3. Rebase:

  git rebase remotes/origin/trunk

4. Post the change to JIRA and get it reviewed.
5. Push the change back to Apache

git push origin trunk

Github Workflow

Apache doesn't seem to provide a place to stash your work-in-progress branches or provide some of the nice social features github has. This can be a problem for larger features. Here are instructions for using github as a place to stash your work in progress changes.

Setting Up

1. As in the other workflows begin by checking out kafka (if you haven't already):

  git clone https://git-wip-us.apache.org/repos/asf/kafka.git kafka

This sets up the remote alias "origin" automatically which refers back to the Apache repo.
2. Create a new github repository on your github account to use for stashing changes. There are various ways to do this, I just forked the apache/kafka repo (https://github.com/apache/kafka) which creates a repo https://github.com/jkreps/kafka (where jkreps would be your user name).
3. Add an alias on your local repository to github to avoid typing:

  git remotes add github https://github.com/<your_user>/kafka.git

Now you can push either to origin or to github.

Doing Work

1. You can create a branch named xyz in your local repository and check it out

  git checkout -b xyz remotes/origin/trunk

2. To set up a second machine to work on you can clone the github url.
3. To save your branch to your github repo do

  git push github xyz

4. To pull these changes onto the other machine where you have a copy of the repository you can do:

  git fetch github
  git checkout xyz
  git merge remotes/github/xyz

If you want to push your commits without passwd, please see apache git wiki.

Overview

The Kafka project development ecosystem involves git (for version control), JIRA (for issue tracking) and either GitHub pull requests or Review Board (for reviewing code changes made by contributors). See below for more details.

Patch Review Tool

We have moved the contribution workflow to Github pull requests. The patch review tool has been phased out. If you are submitting a new patch, please use a Github pull request. If you are still interested in learning more about it, you can find the instructions here.

Contributor and Reviewer Workflow

The process for contributing or reviewing a patch is documented in the Contributing Code Changes page.

Committer Workflow

If you are merging a patch attached to a JIRA (and not a GitHub PR), here is a suggested workflow.

Instructions on merging GitHub pull requests are here.

How to get your patches reviewed

Please ping the dev mailing list if you have a patch that needs a review and it will be added to the queue. The following (JIRA link) are issues that currently have patches available and have an assigned reviewer:

 Review and pushing changes back to Apache works just as before.