Developer Guide

This guide explains how to set up your environment for developing on Helm.

Prerequisites

The latest version of Go
A Kubernetes cluster w/ kubectl (optional)
Git

Building Helm

We use Make to build our programs. The simplest way to get started is:

$ make

NOTE: This will fail if not running from the path $GOPATH/src/helm.sh/helm. The directory helm.sh should not be a symlink or build will not find the relevant packages.

If required, this will first install dependencies, rebuild the vendor/ tree, and validate configuration. It will then compile helm and place it in bin/helm.

To run all the tests (without running the tests for vendor/), run make test.

To run Helm locally, you can run bin/helm.

Helm is known to run on macOS and most Linux distributions, including Alpine.

Contribution Guidelines

We welcome contributions. This project has set up some guidelines in order to ensure that (a) code quality remains high, (b) the project remains consistent, and (c) contributions follow the open source legal requirements. Our intent is not to burden contributors, but to build elegant and high-quality open source code so that our users will benefit.

Make sure you have read and understood the main CONTRIBUTING guide:

https://github.com/helm/helm/blob/master/CONTRIBUTING.md

Structure of the Code

The code for the Helm project is organized as follows:

The individual programs are located in cmd/. Code inside of cmd/ is not designed for library re-use.
Shared libraries are stored in pkg/.
The scripts/ directory contains a number of utility scripts. Most of these are used by the CI/CD pipeline.

Go dependency management is in flux, and it is likely to change during the course of Helm's lifecycle. We encourage developers to not try to manually manage dependencies. Instead, we suggest relying upon the project's Makefile to do that for you. With Helm 3, it is recommended that you are on Go version 1.13 or later.

Writing Documentation

Since Helm 3, documentation has been moved to its own repository. When writing new features, please write accompanying documentation and submit it to the helm-www repository.

Git Conventions

We use Git for our version control system. The master branch is the home of the current development candidate. Releases are tagged. If you are working on patches for Helm v2, the branch dev-v2 is the base branch from which Helm 2 releases are cut.

We accept changes to the code via GitHub Pull Requests (PRs). One workflow for doing this is as follows:

Go to your $GOPATH/src directory, then mkdir helm.sh; cd helm.sh and git clone the github.com/helm/helm repository.
Fork that repository into your GitHub account
Add your repository as a remote for $GOPATH/src/helm.sh/helm
Create a new working branch (git checkout -b feat/my-feature) and do your work on that branch.
When you are ready for us to review, push your branch to GitHub, and then open a new pull request with us.

For Git commit messages, we follow the Semantic Commit Messages:

fix(helm): add --foo flag to 'helm install'

When 'helm install --foo bar' is run, this will print "foo" in the
output regardless of the outcome of the installation.

Closes #1234

Common commit types:

fix: Fix a bug or error
feat: Add a new feature
docs: Change documentation
test: Improve testing
ref: refactor existing code

Common scopes:

helm: The Helm CLI
pkg/lint: The lint package. Follow a similar convention for any package
*: two or more scopes

The Deis Guidelines were the inspiration for this section.
Karma Runner defines the semantic commit message idea.

Go Conventions

We follow the Go coding style standards very closely. Typically, running go fmt will make your code beautiful for you.

We also typically follow the conventions recommended by go lint and gometalinter. Run make test-style to test the style conformance.

Effective Go introduces formatting.
The Go Wiki has a great article on formatting.

If you run the make test target, not only will unit tests be run, but so will style tests. If the make test target fails, even for stylistic reasons, your PR will not be considered ready for merging.