Thank you for showing interest in contributing to the Mender project. Connecting with contributors and growing a community is very important to us. We hope you will find what you need to get started on this page.
If you come across any security issue, please bring it to our team's attention as quickly as possible by sending an email to security@mender.io.
Please do not disclose anything in public. Once an issue has been addressed we will publish the fix and acknowledge your finding on our site if you so wish.
There is a helpwanted tag on some tasks in the Mender issue tracker
that have been identified as good candidates for initial contributors.
You can see them in the Help Wanted saved filter.
Pull requests are very welcome, and the maintainers of Mender work hard to stay on top to review and hopefully merge your work.
If your work is significant, it can make sense to discuss the idea with the maintainers and relevant project members upfront. Start a discussion on our Mender Hub forum.
Using commit signoffs and changelog tags is mandatory for all commits; we also encourage that each commit is small and cohesive. See the next sections for details.
Mender is licensed under the Apache License, Version 2.0. To ensure open source license compatibility, we need to keep track of the origin of all commits and make sure they comply with the license. To do this, we follow the same procedure as used by the Linux kernel, and ask every commit to be signed off.
The sign-off is a simple line at the end of the explanation for the patch, which certifies that you wrote it or otherwise have the right to pass it on as an open-source commit. The rules are pretty simple: if you can certify the below (from developercertificate.org):
Developer Certificate of Origin
Version 1.1
Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
660 York Street, Suite 102,
San Francisco, CA 94110 USA
Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.
Developer's Certificate of Origin 1.1
By making a contribution to this project, I certify that:
(a) The contribution was created in whole or in part by me and I
have the right to submit it under the open source license
indicated in the file; or
(b) The contribution is based upon previous work that, to the best
of my knowledge, is covered under an appropriate open source
license and I have the right under that license to submit that
work with modifications, whether created in whole or in part
by me, under the same open source license (unless I am
permitted to submit under a different license), as indicated
in the file; or
(c) The contribution was provided directly to me by some other
person who certified (a), (b) or (c) and I have not modified
it.
(d) I understand and agree that this project and the contribution
are public and that a record of the contribution (including all
personal information I submit with it, including my sign-off) is
maintained indefinitely and may be redistributed consistent with
this project or the open source license(s) involved.
Then you just add a line to every git commit message:
Signed-off-by: Random J Developer <random@developer.example.org>
Use your real name (sorry, no pseudonyms or anonymous contributions).
If you set your user.name and user.email git configs, you can sign your
commit automatically with git commit -s.
Every commit requires a changelog tag to document what has changed from one release to the next. Unlike commit messages, these should be written in a user centric way.
Below is the complete list of possible tags. See also examples in the next section.
-
Changelog: <message>- Use<message>as the changelog entry. Message can span multiple lines, but is terminated by two consecutive newlines. -
Changelog: Title- Use the commit title (the first line) as the changelog entry. -
Changelog: Commit- Use the entire commit message as a changelog entry (but see filtered content below). -
Changelog: None- Don't generate a changelog entry for this commit.
A few things are always filtered from changelog entries: cherry picked from...
lines and Signed-off-by:, which are standard Git strings. In addition, any
reverted commit will automatically remove the corresponding entry from the
changelog output.
One commit can have several changelog tags, which will generate several entries, if desired.
-
Given the commit message:
Fix crash when /etc/mender/mender.conf is empty.This message is understandable by a user, and can therefore be used as is:
Fix crash when /etc/mender/mender.conf is empty. Changelog: Title -
However, given the commit message:
Implement mutex locking around user data.This is very developer centric and doesn't tell the user what changed for him. In this case it's appropriate to give a different changelog message, like this:
Implement mutex locking around user data. Changelog: Fix crash when updating user data fields. -
In some cases it's appropriate not to provide a changelog message, for instance:
Refactor dataProcess(), no functionality change.This is has no visible effect, therefore it's appropriate to add:
Refactor dataProcess(), no functionality change. Changelog: None
More often than not, your pull request will come as a set of commits, not just a single one. This is especially recommended in case of larger changesets.
In that case, please make sure that each commit constitutes a cohesive, logical whole, e.g. modifies a given package, function, or application layer. There are many ways to conceptually divide your changeset, depending on its size and content - this is up to you. It's just important that unrelated changes are not mixed up together in unrelated commits.
This is to ensure that:
- your PR is easy to browse and review
- git log is easier to digest
- Bad:
Refactor X.
Changelog: None
Refactor Y to use X.
...but also, fix some more of X!
Changelog: None
Add tests for X and Y.
Changelog: None
Fix even more of X and Y to make the tests pass, d'oh!
Changelog: None
These commits reflect an ordinary workflow of incremental changes and fixes, but they are unwieldy for review because of (un)related changes being scattered all over.
Use rebase with edits and squashes to rework this into something more cohesive:
- Good:
Refactor and test X.
Changelog: None
Refactor Y to use X, test Y.
Changelog: None
...or even:
Refactor X.
Changelog: None
Add tests for X.
Changelog: None
Refactor Y to use X.
Changelog: None
Add tests for Y.
Changelog: None
We have a Code of Conduct that applies to all contributors and participants to the Mender project.
In an ever more digitized world, securing the world's connected devices is a very important and meaningful task. To succeed, we will need to row in the same direction and work to the best interest of the project.
This project appreciates your friendliness, transparency and a collaborative spirit.