The Crossplane project is under Apache 2.0 license. We accept contributions via GitHub pull requests. This document outlines some of the conventions related to development workflow, commit message formatting, contact points and other resources to make it easier to get your contribution accepted.
By contributing to this project you agree to the Developer Certificate of Origin (DCO). This document was created by the Linux Kernel community and is a simple statement that you, as a contributor, have the legal right to make the contribution. See the DCO file for details.
Contributors sign-off that they adhere to these requirements by adding a Signed-off-by line to commit messages. For example:
This is my commit message
Signed-off-by: Random J Developer <random@developer.example.org>
Git even has a -s command line option to append this automatically to your commit message:
git commit -s -m 'This is my commit message'
If you have already made a commit and forgot to include the sign-off, you can amend your last commit to add the sign-off with the following command, which can then be force pushed.
git commit --amend -s
We use a DCO bot to enforce the DCO on each pull request and branch commits.
- Fork the repository on GitHub
- Read the install for build and test instructions
- Play with the project, submit bugs, submit patches!
This is a rough outline of what a contributor's workflow looks like:
- Open an issue against this repository to propose your change.
- Consider writing a one-pager or design doc if your proposal seems complex or controversial.
- Create a branch from where you want to base your work (usually master).
- Make your changes and arrange them in readable commits.
- Make sure your commit messages are in the proper format (see below).
- Push your changes to the branch in your fork of the repository.
- Make sure all linters and tests pass, and add any new tests as appropriate.
- Submit a pull request to the original repository.
Details about building crossplane can be found in INSTALL.md.
Crossplane projects are written in Go. Coding style is enforced by golangci-lint. Crossplane's linter configuration is documented here. Builds will fail locally and in CI if linter warnings are introduced:
$ make build
==> Linting /REDACTED/go/src/github.com/crossplaneio/crossplane/cluster/charts/crossplane
[INFO] Chart.yaml: icon is recommended
1 chart(s) linted, no failures
20:31:42 [ .. ] helm dep crossplane 0.1.0-136.g2dfb012.dirty
No requirements found in /REDACTED/go/src/github.com/crossplaneio/crossplane/cluster/charts/crossplane/charts.
20:31:42 [ OK ] helm dep crossplane 0.1.0-136.g2dfb012.dirty
20:31:42 [ .. ] golangci-lint
pkg/clients/azure/redis/redis.go:35:7: exported const `NamePrefix` should have comment or be unexported (golint)
const NamePrefix = "acr"
^
20:31:55 [FAIL]
make[2]: *** [go.lint] Error 1
make[1]: *** [build.all] Error 2
make: *** [build] Error 2Note that Jenkins builds will not output linter warnings in the build log.
Instead upbound-bot will leave comments on your pull request when a build
fails due to linter warnings. You can run make lint locally to help determine
whether you've fixed any linter warnings detected by Jenkins.
In some cases linter warnings will be false positives. golangci-lint supports
//nolint[:lintername] comment directives in order to quell them. Please
include an explanatory comment if you must add a //nolint comment. You may
also submit a PR against .golangci.yml if you feel
particular linter warning should be permanently disabled.
Comments should be added to all new methods and structures as is appropriate for the coding language. Additionally, if an existing method or structure is modified sufficiently, comments should be created if they do not yet exist and updated if they do.
The goal of comments is to make the code more readable and grokkable by future developers. Once you have made your code as understandable as possible, add comments to make sure future developers can understand (A) what this piece of code's responsibility is within Crossplane's architecture and (B) why it was written as it was.
The below blog entry explains more the why's and how's of this guideline. https://blog.codinghorror.com/code-tells-you-how-comments-tell-you-why/
For Go, Crossplane follows standard godoc guidelines. A concise godoc guideline can be found here: https://blog.golang.org/godoc-documenting-go-code
We follow a rough convention for commit messages that is designed to answer two questions: what changed and why. The subject line should feature the what and the body of the commit should describe the why.
aws: add support for RDS controller
this commit enables controllers and apis for RDS. It
enables provisioning a RDS database.
The format can be described more formally as follows:
<subsystem>: <what changed>
<BLANK LINE>
<why this change was made>
<BLANK LINE>
<footer>
The first line is the subject and should be no longer than 70 characters, the second line is always blank, and other lines should be wrapped at 80 characters. This allows the message to be easier to read on GitHub as well as in various git tools.
To prepare your branch to open a PR, you will need to have the minimal number of logical commits so we can maintain a clean commit history. Most commonly a PR will include a single commit where all changes are squashed, although sometimes there will be multiple logical commits. Please refer to git documentation for more information regarding rewriting the history.
When addressing pull request comments, individual commits could be created to clearly indicate the change that results from addressing in each iteration. However, once all comments are addressed and reviewer have signed off, the feedback commits should all be squashed into the original logical change commits.
To learn more about the developer iteration workflow, including how to locally test new types/controllers, please refer to the Local Build instructions.