Contributing to krm-functions-catalog#

We'd love to accept your contributions to this project. There are just a few
small guidelines you need to follow.

Developer Certificate of Origin (DCO)#

Contributors to this project should state that they agree with the terms published at https://developercertificate.org/
for their contribution. To do this when creating a commit with the Git CLI, a sign-off can be added with
the -s option. The sign-off is stored as part of the commit message
itself.

Copyright notices#

All files should have the copyright notice.

// Copyright 2026 The kpt Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

If the file has never been modified: use the creation year only

Example: Copyright 2026 The kpt Authors

If the file has been modified: use a year range from creation to last modification

Example: Copyright 2024-2026 The kpt Authors

Code reviews#

All submissions, including submissions by project members, require review. We
use GitHub pull requests for this purpose. Consult GitHub Help for more
information on using pull requests.

Process for code reviews. Before requesting human review, a PR must:

All tests passing
All linting passing
Meeting project code quality requirements, including passing all configured static analysis / SonarCloud quality gates and not reducing automated test coverage for the affected components
The comments from the first run of automatically generated comments (AI generated comments, SonarCloud comments, bot generated comments, etc.) of the PR are addressed (addressing further re-runs of AI are optional)
If it is not possible to resolve an automatic comment, please add a sub-comment indicating why the automated comment cannot be resolved or ask for help in resolving the comment
The PR description states whether AI was used to help create the PR; if so, it lists the AI tools used and the areas where they were used

Declare any use of AI#

In addition to the above, the use of AI in the creation of PRs is allowed, but you must declare any use of AI and you must be able to explain the PR code independently of any AI tools.

Update the PR description to state whether you used AI to help you create this PR; if so, list the AI tools you have used and in what areas.

For example:

I have used AI in the creation of this PR.

I have used the following AI tools:
- GitHub Copilot to analyze the code
- Claude Code to generate the function someNewFunctionIAdded()
- Amazon Q to generate unit tests

Attribute AI in the Git commit messages#

Following the guidance of the Linux kernel
we recommend the attribution of AI tools in the commit messages using the following format:

Assisted-by: AGENT_NAME:MODEL_VERSION [TOOL1] [TOOL2]

Where:

AGENT_NAME is the name of the AI tool or framework
MODEL_VERSION is the specific model version used
[TOOL1] [TOOL2] are optional specialized analysis tools used (e.g., coccinelle, sparse, smatch, clang-tidy)

Basic development tools (git, gcc, make, editors) should not be listed.

Example:

Assisted-by: Claude:claude-3-opus coccinelle sparse

Style Guides#

Contributions are required to follow these style guides:

How to Contribute#

Repo Layout#

├── examples: Home for all function examples
│ ├── function_bar_example
│ └── function_foo_example
├── functions
│ └── go: Home for all golang-based function source code
│ ├── Makefile
│ ├── go_function_bar
│ └── go_function_foo
├── scripts
├── tests: Home for e2e tests
└── build
      └── docker
          └── go: Home for default golang Dockerfile
               └── Dockerfile

For each function, its files spread in the follow places:

functions/ directory: Each function must have its own directory in one
of functions/ sub-directory. In each function's directory, it must have the
following:
- Source code (and unit tests).
- A README.md file serving as the usage doc and will be shown in
  the catalog website. Functions should follow this template.
- A metadata.yaml file that follows the function metadata schema.
- (Optional) A Dockerfile to build the docker container. If a Dockerfile is
  not defined, the default Dockerfile for the language will
  be used.
examples/ directory: It contains examples for functions, and these examples
are also being tested as e2e tests. Each function should have at least one
example here. There must be a README.md file in each example directory, and it
should follow the template.
The tests/ directory contains the e2e test harness (tests/e2etest/) which
scans both examples/ and functions/go/*/tests/ for test cases.
Each function may also have a tests/ subdirectory inside its source
directory (functions/go/<fn>/tests/) for edge case and error handling tests
that are not suitable as user-facing examples.
master branch should should contain examples with the latest tag for
your function images. When you release the function version that tag should
have the samples and tests that match the function version.

For golang-based functions, you need to generate some doc related variables from
the README.md by running

$ cd functions/go
$ make generate

Tests#

Unit Tests#

To run all unit tests

$ make unit-test

Building a function image#

Note: We use docker buildx to build images. Please ensure you have it installed.

To build all function images

$ make build

To build a single function image (e.g. apply-setters)

$ cd functions/go
$ make apply-setters-BUILD

E2E Tests#

The e2e tests are the recommended way to test functions in the catalog. They are
very easy to write and set up with our e2e test harness. You can find all the
supported options and expected test directory
structure here.

You can choose to put the e2e test in either the examples/ directory or in
the function's tests/ subdirectory (functions/go/<fn>/tests/) depending on
whether it is worthwhile to be shown as a user-facing example.

Note: The e2e tests don't build the images. So you need to ensure you have built
the latest image(s) before running any e2e tests.

To test a specific example or the e2e test, run

$ cd tests/e2etest
$ go test -v ./... -run TestE2E/../../examples/$EXAMPLE_NAME

# To test edge case tests for a specific function
$ go test -v ./... -run TestE2E/../../functions/go/$FUNCTION_NAME/tests/$TEST_NAME

# To run all tests for a specific function (examples + edge cases)
$ go test -v ./... -run "TestE2E/../../examples/$FUNCTION_NAME"
$ go test -v ./... -run "TestE2E/../../functions/go/$FUNCTION_NAME/tests"

If you encounter some test failure saying something like "actual diff doesn't
match expected" or "actual results doesn't match expected", you can update the
expected diff.patch or results.yaml by running the following commands:

# Update one example
$ KPT_E2E_UPDATE_EXPECTED=true go test -v ./... -run TestE2E/../../examples/$EXAMPLE_NAME

# Update one edge case test
$ KPT_E2E_UPDATE_EXPECTED=true go test -v ./... -run TestE2E/../../functions/go/$FUNCTION_NAME/tests/$TEST_NAME

# Update all examples
$ KPT_E2E_UPDATE_EXPECTED=true go test -v ./...

Most contributors don't need this, but if you happen to need to test all
examples and e2e tests, run the following command

$ make e2e-test

Documentation#

For details on running the documentation site locally, refer to the
documentation README.

Change Existing Functions#

You must follow the layout convention when you make changes to existing
functions.

If you implement a new feature, you must add a new example or modify existing
one to cover it.

If you fix a bug, you must add (unit or e2e) tests to cover that.

Contribute New Functions#

You must follow the layout convention when you contribute new functions.

You need to add new function name to the respective Makefile.

functions/go/Makefile for golang.

Contact Us#

Do you need a review or release of functions? We’d love to hear from you!

Message our Slack channel
Join our discussions