This document is a guide on how to best contribute to this project.
SHOULD describes optional steps. MUST describes mandatory steps.
SHOULD NOT and MUST NOT describes pitfalls to avoid.
Your local copy refers to the copy of the repository that you have on your computer. origin refers to your fork of the project. upstream refers to the official repository for this project.
For general discussion about this project, please open a ticket. Feedback is always welcome and may transform in tasks to improve the project, so having the discussion start there is a plus.
Alternatively you may try the Discord server or, if you need the discussion to stay private, you can send an email at [email protected].
Free support is generally not available. The rule is that free support is only given if doing so benefits most users. In practice this means that free support will only be given if the issues are due to a fault in the project itself or its documentation.
Paid support is available for all price ranges. Please send an email to [email protected] for more information.
You SHOULD open a ticket for every bug you encounter, regardless of the version you use. A ticket not only helps the project ensure that bugs are squashed, it also helps other users who later run into this issue. You SHOULD give as much information as possible including what commit/branch, what OS/version and so on.
You SHOULD NOT open a ticket if another already exists for the same issue. You SHOULD instead either add more information by commenting on it, or simply comment to inform the maintainer that you are also affected. The maintainer SHOULD reply to every new ticket when they are opened. If the maintainer didn’t say anything after a few days, you SHOULD write a new comment asking for more information.
You SHOULD provide a reproducible test case, either in the ticket or by sending a pull request and updating the test suite.
When you have a fix ready, you SHOULD open a pull request, even if the code does not fit the requirements discussed below. Providing a fix, even a dirty one, can help other users and/or at least get the maintainer on the right tracks.
You SHOULD try to relax and be patient. Some tickets are merged or fixed quickly, others aren’t. There’s no real rules around that. You can become a paying customer if you need something fast.
You SHOULD open a ticket when you identify a DoS vulnerability in this project. You SHOULD include the resources needed to DoS the project; every project can be brought down if you have the necessary resources.
You SHOULD send an email to [email protected] when you identify a security vulnerability. If the vulnerability originates from code inside Erlang/OTP itself, you SHOULD also consult with OTP Team directly to get the problem fixed upstream.
Feature requests are always welcome. To be accepted, however, they must be well defined, make sense in the context of the project and benefit most users.
Feature requests not benefiting most users may only be accepted when accompanied with a proper pull request.
You MUST open a ticket to explain what the new feature is, even if you are going to submit a pull request for it.
All these conditions are meant to ensure that the project stays lightweight and maintainable.
You SHOULD follow the code submission guidelines to submit documentation.
The documentation is available in the 'doc/src/' directory. There are three kinds of documentation: manual, guide and tutorials. The format for the documentation is Asciidoc.
You SHOULD follow the same style as the surrounding documentation when editing existing files.
You MUST include the source when providing media.
You SHOULD follow the code submission guidelines to submit examples.
The examples are available in the 'examples/' directory.
You SHOULD focus on exactly one thing per example.
You SHOULD open a pull request to submit code.
You SHOULD open a ticket to discuss backward incompatible changes before you submit code. This step ensures that you do not work on a large change that will then be rejected.
You SHOULD send your code submission using a pull request on GitHub. If you can’t, please send an email to [email protected] with your patch.
The following sections explain the normal GitHub workflow.
You MUST fork the project’s repository on GitHub by clicking on the Fork button.
On the right page of your fork’s page is a field named SSH clone URL.
Its contents will be identified as $ORIGIN_URL in the following snippet.
On the right side of the project’s repository page is a similar field.
Its contents will be identified as $UPSTREAM_URL.
Finally, $PROJECT is the name of this project.
To setup your clone and be able to rebase when requested, run the following commands:
$ git clone $ORIGIN_URL
$ cd $PROJECT
$ git remote add upstream $UPSTREAM_URLYou SHOULD base your branch on master, unless your patch applies to a stable release, in which case you need to base your branch on the stable branch, for example 1.0.x.
The first step is therefore to checkout the branch in question:
$ git checkout 1.0.xThe next step is to update the branch to the current version from upstream. In the following snippet, replace 1.0.x by master if you are patching master.
$ git fetch upstream
$ git rebase upstream/1.0.xThis last command may fail and ask you to stash your changes. When that happens, run the following sequence of commands:
$ git stash
$ git rebase upstream/1.0.x
$ git stash popThe final step is to create a new branch you can work in. The name
of the new branch is up to you, there is no particular requirement.
Replace $BRANCH with the branch name you came up with:
$ git checkout -b $BRANCHYour local copy is now ready.
There are very few rules with regard to source code editing.
You MUST use horizontal tabs for indentation. Use one tab per indentation level.
You MUST NOT align code. You can only add or remove one indentation level compared to the previous line.
You SHOULD NOT write lines more than about a hundred characters. There is no hard limit, just try to keep it as readable as possible.
You SHOULD write small functions when possible.
You SHOULD avoid a too big hierarchy of case clauses inside a single function.
You SHOULD add tests to make sure your code works.
You SHOULD run Dialyzer and the test suite while working on your patch, and you SHOULD ensure that no additional tests fail when you finish.
You can use the following command to run Dialyzer:
$ make dialyzeYou have two options to run tests. You can either run tests across all supported Erlang versions, or just on the version you are currently using.
To test across all supported Erlang versions:
$ make -k ciTo test using the current version:
$ make testsYou can then open Common Test logs in 'logs/all_runs.html'.
By default Cowboy excludes a few test suites that take too long to complete. For example all the examples are built and tested, and one Websocket test suite is very extensive. In order to run everything, do:
$ make tests FULL=1Once all tests pass (or at least, no new tests are failing), you can commit your changes.
First you need to add your changes:
$ git add src/file_you_edited.erlIf you want an interactive session, allowing you to filter out changes that have nothing to do with this commit:
$ git add -pYou MUST put all related changes inside a single commit. The general rule is that all commits must pass tests. Fix one bug per commit. Add one feature per commit. Separate features in multiple commits only if smaller parts of the feature make sense on their own.
Finally once all changes are added you can commit. This command will open the editor of your choice where you can put a proper commit title and message.
$ git commitDo not use the -m option as it makes it easy to break the
following rules:
You MUST write a proper commit title and message. The commit title is the first line and MUST be at most 72 characters. The second line MUST be left blank. Everything after that is the commit message. You SHOULD write a detailed commit message. The lines of the message MUST be at most 80 characters. You SHOULD explain what the commit does, what references you used and any other information that helps understanding why this commit exists. You MUST NOT include commands to close GitHub tickets automatically.
If you create a new commit every time you make a change, however insignificant, you MUST consolidate those commits before sending the pull request.
This is done through rebasing. The easiest way to do so is
to use interactive rebasing, which allows you to choose which
commits to keep, squash, edit and so on. To rebase, you need
to give the original commit before you made your changes. If
you only did two changes, you can use the shortcut form HEAD^^:
$ git rebase -i HEAD^^You MUST push your branch to your fork on GitHub. Replace
$BRANCH with your branch name:
$ git push origin $BRANCHYou can then submit the pull request using the GitHub interface. You SHOULD provide an explanatory message and refer to any previous ticket related to this patch. You MUST NOT include commands to close other tickets automatically.
Sometimes the maintainer will ask you to change a few things. Other times you will notice problems with your submission and want to fix them on your own.
In either case you do not need to close the pull request. You can just push your changes again and, if needed, force them. This will update the pull request automatically.
$ git push -f origin $BRANCHThis is an open source project maintained by independent developers. Please be patient when your changes aren’t merged immediately.
All pull requests run through a Continuous Integration service to ensure nothing gets broken by the changes submitted.
Bug fixes will be merged immediately when all tests pass. The maintainer may do style changes in the merge commit if the submitter is not available. The maintainer MUST open a new ticket if the solution could still be improved.
New features and backward incompatible changes will be merged when all tests pass and all other requirements are fulfilled.