CONTRIBUTING.md

We welcome contributions from the community. Please read the following guidelines carefully to maximize the chances of your PR being merged.

Communication

• Before starting work on a major feature, please reach out to us via GitHub, Slack, email, etc. We will make sure no one else is already working on it and ask you to open a GitHub issue.
• A "major feature" is defined as any change that is > 100 LOC altered (not including tests), or changes any user-facing behavior. We will use the GitHub issue to discuss the feature and come to agreement. This is to prevent your time being wasted, as well as ours. The GitHub review process for major features is also important so that organizations with commit access can come to agreement on design.
• Small patches and bug fixes don't need prior communication.

Coding style

• See STYLE.md

Maintaining clean commit history

The following conventions should be followed for keeping history clean and making code reviews easier for reviewers:

• First line of commit messages should be in format of

  package-name: summary of change

  for example:

  cache,server: improve caching behaviour

• Every time you receive a feedback on your pull request, push changes that address it as a separate one or multiple commits with a descriptive commit message (try to avoid using vague addressed pr feedback type of messages).

  Project maintainers are obligated to squash those commits into one when merging.

Submitting a PR

• Fork the repo.
• Create your PR.
• Tests will automatically run for you.
• We will not merge any PR that is not passing tests.
• PRs are expected to have 100% test coverage for added code. This can be verified with a coverage build. If your PR cannot have 100% coverage for some reason please clearly explain why when you open it.
• All code comments and documentation are expected to have proper English grammar and punctuation. If you are not a fluent English speaker (or a bad writer ;-)) please let us know and we will try to find some help but there are no guarantees.
• Your PR title should be descriptive, and generally start with a subsystem name followed by a colon. Examples:
  • "docs: fix grammar error"
  • "http conn man: add new feature"
• Your PR description should have details on what the PR does. If it fixes an existing issue it should end with "Fixes #XXX".
• When all of the tests are passing and all other conditions described herein are satisfied, we will review it and merge.
• Once you submit a PR, please do not rebase it. It's much easier to review if subsequent commits are new commits and/or merges. We squash rebase the final merged commit so the number of commits you have in the PR don't matter.
• We expect that once a PR is opened, it will be actively worked on until it is merged or closed. We reserve the right to close PRs that are not making progress. This is generally defined as no changes for 7 days. Obviously PRs that are closed due to lack of activity can be reopened later. Closing stale PRs helps us keep on top of all of the work currently in flight.
• If a commit deprecates a feature, the commit message must mention what has been deprecated.
• Please consider joining the envoy-dev mailing list.

PR review policy for maintainers

• Typically we try to turn around reviews within one business day.
• See OWNERS.md for the current list of maintainers.
• It is generally expected that a senior maintainer should review every PR.
• It is also generally expected that a "domain expert" for the code the PR touches should review the PR. This person does not necessarily need to have commit access.
• The previous two points generally mean that every PR should have two approvals. (Exceptions can be made by the senior maintainers).
• The above rules may be waived for PRs which only update docs or comments, or trivial changes to tests and tools (where trivial is decided by the maintainer in question).
• In general, we should also attempt to make sure that at least one of the approvals is from an organization different from the PR author. E.g., if Lyft authors a PR, at least one approver should be from an organization other than Lyft. This helps us make sure that we aren't putting organization specific shortcuts into the code.
• If there is a question on who should review a PR please discuss in Slack.
• Anyone is welcome to review any PR that they want, whether they are a maintainer or not.
• Please clean up the commit message before merging. By default, GitHub fills the squash merge commit message with every individual commit from the PR. Generally, we want a commit message that is roughly equal to the original PR title and description.
• If a PR includes a deprecation/breaking change, notification should be sent to the envoy-announce email list.

DCO: Sign your work

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 patch. 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: Joe Smith <joe@gmail.com>

using your real name (sorry, no pseudonyms or anonymous contributions.)

You can add the sign off when creating the git commit via git commit -s.

If you want this to be automatic you can set up some aliases:

git config --add alias.amend "commit -s --amend"
git config --add alias.c "commit -s"

Fixing DCO

If your PR fails the DCO check, it's necessary to fix the entire commit history in the PR. Best practice is to squash the commit history to a single commit, append the DCO sign-off as described above, and force push. For example, if you have 2 commits in your history:

git rebase -i HEAD^^
(interactive squash + DCO append)
git push origin -f

Note, that in general rewriting history in this way is a hindrance to the review process and this should only be done to correct a DCO mistake.