Contributing to Apache Camel

There are many ways you can help make Camel a better piece of software - please dive in and help!

  • Try surfing the documentation - if something confuses you, bring it to our attention.
  • Download the code & try it out and see what you think.
  • Browse the source code. Got an itch to scratch, want to tune some operation, or add some feature?
  • Want to do some hacking on Camel? Try surfing our issue tracker for open issues or features that need to be implemented, take active ownership of a particular issue, and try to fix it.
  • If you are a new Camel rider and would like to help us, you can also find some easy to resolve issues.
  • Leave a comment on the issue to let us know you are working on it, and add yourself as a watcher to get informed about all modifications.

Table of Contents

Getting in touch

There are various ways of communicating with the Camel community.

Improving the documentation

Documentation is massively critical for users intending to make the most of Apache Camel, and it‘s probably the area that needs the most help! So if you are interested in helping with the documentation efforts, whether it’s just to fix a page here or there, correct a link, or even write a tutorial or improve existing documentation, please dive in and help! We moved the documentation into the code (AsciiDoc). We are not using the wiki system anymore.

To edit the documentation:

  • It's easy as opening a Pull Request
  • You'll find on each component under src/main/docs a .adoc file
    • This file contains a static part and a dynamically generated part: the former can be edited directly in the .adoc file, while the latter needs your intervention on the Javadoc
    • Once you modify the Javadoc, you'll need to rebuild the component. And, the .adoc file will get automatically updated.
    • Create a commit and raise a Pull Request
  • If you want to add more documentation, find the respective .adoc in the codebase

For more information, see How does the website work or How do I edit the website for more details.

If you find a bug or problem

Please raise a new issue in our issue tracker If you can create a JUnit test case, then your issue is more likely to be resolved quicker. e.g., take a look at some of the existing unit tests cases

Working on the code

We recommend working on the code from github.

git clone https://github.com/apache/camel.git
cd camel

Build the project (fast build).

mvn clean install -Pfastinstall

If you intend to work on the code and provide patches and other work you want to submit to the Apache Camel project, then you can fork the project on GitHub and work on your fork. Your custom-work needs to be on your self-created branches, which can then be committed and pushed upstream, and then submitted to Apache Camel as PRs (pull requests). You can find many resources online on how to work on GitHub projects and how to submit work to these projects.

Please avoid unnecessary changes, like reordering methods and fields, which will make your PR easier to review.

Running checkstyle

Apache Camel source code is using a coding style/format that can be verified for its compliance using the checkstyle plugin. To enable source style checking with checkstyle, build Camel with the -Psourcecheck parameter:

mvn clean install -Psourcecheck

Please remember to run this check on your code changes before submitting a patch or Github PR. You do not need to run this against the entire project, but only in your modules. Let's say you do some code changes in the camel-ftp component, following which you can run the check from within this directory:

cd camel-ftp
mvn clean install -Psourcecheck

Verify Karaf features

Camel-Karaf now lives in its self repository, so to verify a Karaf feature, you'll need to fork the following repository.

To check a new Karaf feature or an existing one, you should run a verification on the features.xml file. You'll need to follow these steps: The first thing to be done is running a full build of Camel. Then

cd platform/karaf/features/
mvn clean install

If you modified a component/dataformat or updated a dependency in the main camel repository, you'll first need to build the main camel locally and then run a full build of camel-karaf.

Apache Camel committers should work on the ASF git repo

If you are an Apache Camel committer, then clone the ASF git repo at

git clone https://gitbox.apache.org/repos/asf/camel.git
cd camel

or

git clone https://github.com/apache/camel.git
cd camel

Build the project (without testing).

mvn clean install -Dtest=false

PS: You might need to build multiple times (if you get a build error) because sometimes the maven fails to download all the files. Then import the projects into your workspace.

Creating patches

We recommend you create patches as GitHub PRs as it eases our reviewing process enables faster review completion. You do this as any other GitHub project, where you can fork the project, and create a branch where you work on the code, and then commit and push that code to your fork. Then navigate to the Apache Camel GitHub webpage, and you will see that GitHub at the top of the page has a wizard to send your recent work as a PR (pull request).

Pull request at Github

There is also a Git repository at GitHub which you could fork. Then you submit patches as any other GitHub project - e.g., work on a new feature branch and send a pull request. One of the committers then needs to accept your pull request to bring the code to the ASF codebase.

When providing code patches, please include the Camel JIRA ticket number in the commit messages. We favor using the syntax:

CAMEL-9999: Some message goes here

Manual patch files

We gladly accept patches if you can find ways to improve, tune, or fix Camel in some way.

We recommend using GitHub PRs instead of manual patch files. Especially for larger patches.

Most IDEs can create nice patches now very easily. e.g., on Eclipse, right-click on a file/directory, and select Team -> Create Patch. Then, save the patch as a file and attach it to the corresponding issue on our JIRA issue tracker. If you prefer working on the command-line, try the following to create the patch:

diff -u Main.java.orig Main.java >> patchfile.txt

or

git diff --no-prefix > patchfile.txt

Submitting patches

The easiest way to submit a patch is to

  • create a new JIRA issue (you will need to register),
  • attach the patch or tarball as an attachment (if you create a patch file, but we recommend using GitHub PRs)
  • tick the Patch Attached button on the issue We prefer patches to have unit tests as well and that these unit tests have proper assertions as well, so remember to replace your system.out or logging with appropriate assertions.

Using the issue tracker

Before you can raise an issue in the issue tracker, you need to register with it: This is quick & painless.

Becoming a committer

Once you've got involved as above, we may well invite you to be a committer. See How do I become a committer for more details.

The first step is contributing to the project; if you want to take that a step forward and become a fellow committer on the project, please check out our Committer Guide.