This document is the single source of truth for how to contribute to the code base. We'd love to accept your patches and contributions to this project. There are just a few small guidelines you need to follow.
As you will notice we do not, currently, require any CLA signature. This may change in the future anyway but if so even that change will follow the contributing guidelines and processes.
Follow these instructions if you want to
Become a member of the K3ai GitHub org (see below)
Be recognized as an individual or organization contributing to K3ai
Before asking to join the community, we ask that you first make a small number of contributions to demonstrate your intent to continue contributing to K3ai.
There are a number of ways to contribute to K3ai
File issues reporting bugs or providing feedback
Answer questions on Slack or GitHub issues
When you are ready to join
Send a PR adding yourself as a member in org.yaml
After the PR is merged an admin will send you an invitation
This is a manual process we are a very small team so please be patient
If a week passes without receiving an invitation reach out on k3ai#community
Help is always welcome! For example, documentation (like the text you are reading now) can always use improvement. There's always code that can be clarified and variables or functions that can be renamed or commented on. There's always a need for more test coverage. You get the idea - if you ever see something you think should be fixed, you should own it. Here is how you get started.
To find K3ai issues that make good entry points:
Start with issues labeled good first issue.
For issues that require deeper knowledge of one or more technical aspects,
look at issues labeled help wanted.
Examine the issues in any of the
Owners files and PR workflow
Overview of OWNERS files
Nov. 2020 We are not yet to the point where we use OWNERS and/or REVIEWERS but we plan things in advance so the below represents the idea of future workflows.
OWNERS files are used to designate responsibility for different parts of the K3ai codebase. Today, we use them to assign the reviewer and approver roles used in our two-phase code review process.
The velocity of a project that uses code review is limited by the number of people capable of reviewing code. The quality of a person's code review is limited by their familiarity with the code under review. Our goal is to address both of these concerns through the prudent use and maintenance of OWNERS files
Each directory that contains a unit of independent code or content may also contain an OWNERS file. This file applies to everything within the directory, including the OWNERS file itself, sibling files, and child directories.
OWNERS files are in YAML format and support the following keys:
approvers: a list of GitHub usernames or aliases that can
/approve a PR
labels: a list of GitHub labels to automatically apply to a PR
options: a map of options for how to interpret this OWNERS file, currently only one:
no_parent_owners: defaults to
false if not present; if
true, exclude parent OWNERS files.
Allows the use case where
a/deep/nested/OWNERS file prevents
a/OWNERS file from having any
reviewers: a list of GitHub usernames or aliases that are good candidates to
/lgtm a PR
All users are expected to be assignable. In GitHub terms, this means they are either collaborators of the repo, or members of the organization to which the repo belongs.
A typical OWNERS file looks like:
approvers:- alice- bob# this is a commentreviewers:- alice- carol# this is another comment- sig-foo # this is an alias
Each repo may contain at its root an OWNERS_ALIAS file.
OWNERS_ALIAS files are in YAML format and support the following keys:
aliases: a mapping of alias name to a list of GitHub usernames
We use aliases for groups instead of GitHub Teams, because changes to GitHub Teams are not publicly auditable.
A sample OWNERS_ALIASES file looks like:
aliases:sig-foo:- david- erinsig-bar:- bob- frank
GitHub usernames and aliases listed in OWNERS files are case-insensitive.
The code review process
The author submits a PR
Phase 0: Automation suggests reviewers and approvers for the PR Determine the set of OWNERS files nearest to the code being changed Choose at least two suggested reviewers , trying to find a unique reviewer for every leaf OWNERS file, and request their reviews on the PR Choose suggested approvers , one from each OWNERS file, and list them in a comment on the PR
Phase 1: Humans review the PR
Reviewers look for general code quality, correctness, sane software engineering, style, etc.
Anyone in the organization can act as a reviewer with the exception of the individual who
opened the PR
If the code changes look good to them, a reviewer types
/lgtm in a PR comment or review;
if they change their mind, they
Phase 2: Humans approve the PR
The PR author
/assign's all suggested approvers to the PR, and optionally notifies
them (eg: "pinging @foo for approval")
Only people listed in the relevant OWNERS files, either directly or through an alias, can act
as approvers, including the individual who opened the PR
Approvers look for holistic acceptance criteria, including dependencies with other features,
forwards/backwards compatibility, API and flag definitions, etc
If the code changes look good to them, an approver types
/approve in a PR comment or
review; if they change their mind, they
Phase 3: Automation merges the PR:
If all of the following are true:
All required labels are present (eg:
Any blocking labels are missing (eg: there is no
And if any of the following are true:
there are no presubmit prow jobs configured for this repo
there are presubmit prow jobs configured for this repo, and they all pass after automatically
being re-run one last time
Then the PR will automatically be merged
Quirks of the process
There are a number of behaviors we've observed that while possible are discouraged, as they go against the intent of this review process. Some of these could be prevented in the future, but this is the state of today.
/lgtm is simultaneously interpreted as an
While a convenient shortcut for some, it can be surprising that the same command is interpreted
in one of two ways depending on who the commenter is
Instead, explicitly write out
/approve to help observers, or save the
This goes against the idea of having at least two sets of eyes on a PR, and may be a sign that
there are too few reviewers (who aren't also approver)
Technically, anyone who is a member of the K3ai GitHub organization can drive-by
Drive-by reviews from non-members are encouraged as a way of demonstrating experience and
intent to become a collaborator or reviewer
/lgtm's from members may be a sign that our OWNERS files are too small, or that the
existing reviewers are too unresponsive
This goes against the idea of specifying reviewers in the first place, to ensure that
author is getting actionable feedback from people knowledgeable with the code
Reviewers, and approvers are unresponsive
This causes a lot of frustration for authors who often have little visibility into why their
PR is being ignored
Many reviewers and approvers are so overloaded by GitHub notifications that @mention'ing
is unlikely to get a quick response
If an author
/assign's a PR, reviewers and approvers will be made aware of it on
their PR dashboard
An author can work around this by manually reading the relevant OWNERS files,
/unassign'ing unresponsive individuals, and
This is a sign that our OWNERS files are stale; pruning the reviewers and approvers lists
would help with this
It is the PR authors responsibility to drive a PR to resolution. This means if the PR reviewers are unresponsive they should escalate as noted below
e.g ping reviewers in a timely manner to get it reviewed
If the reviewers don't respond look at the OWNERs file in root and ping approvers listed there
Authors are unresponsive
This costs a tremendous amount of attention as context for an individual PR is lost over time
This hurts the project in general as its general noise level increases over time
Instead, close PR's that are untouched after too long (we currently have a bot do this after 30
Automation using OWNERS files prow
Prow receives events from GitHub, and reacts to them. It is effectively stateless. The following pieces of prow are used to implement the code review process above. per-repo configuration: labels : list of labels required to be present for merge (eg: lgtm ) missingLabels : list of labels required to be missing for merge (eg: do-not-merge/hold ) reviewApprovedRequired : defaults to false ; when true, require that there must be at least present for merge merge_method : defaults to merge ; when squash or rebase , use that merge method instead when clicking a PR's merge button merges PR's once they meet the appropriate criteria as configured above if there are any presubmit prow jobs for the repo the PR is against, they will be re-run one final time just prior to merge assigns GitHub users in response to /assign comments on a PR unassigns GitHub users in response to /unassign comments on a PR per-repo configuration: issue_required : defaults to false ; when true , require that the PR description link to an issue, or that at least one approver issues a /approve no-issue implicit_self_approve : defaults to false ; when true , if the PR author is in relevant OWNERS files, act as if they have implicitly /approve 'd adds the approved label once an approver for each of the required OWNERS files has /approve 'd comments as required OWNERS files are satisfied removes outdated approval status comments determines reviewers and requests their reviews on PR's adds the lgtm label when a reviewer comments /lgtm on a PR the PR author may not /lgtm their own PR parses OWNERS and OWNERS_ALIAS files if the no_parent_owners option is encountered, parent owners are excluded from having any influence over files adjacent to or underneath of the current OWNERS file
Maintaining OWNERS files
OWNERS files should be regularly maintained.
We encourage people to self-nominate or self-remove from OWNERS files via PR's. Ideally in the future we could use metrics-driven automation to assist in this process.
We should strive to:
grow the number of OWNERS files
add new people to OWNERS files
ensure OWNERS files only contain org members and repo collaborators
ensure OWNERS files only contain people are actively contributing to or reviewing the code they own
remove inactive people from OWNERS files
Bad examples of OWNERS usage:
directories that lack OWNERS files, resulting in too many hitting root OWNERS
OWNERS files that have a single person as both approver and reviewer
OWNERS files that haven't been touched in over 6 months
OWNERS files that have non-collaborators present
Good examples of OWNERS usage:
there are more
approvers are not i