chart-testing/README.md

# Chart Testing

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`ct` is the the tool for testing Helm charts.
It is meant to be used for linting and testing pull requests.
It automatically detects charts changed against the target branch.

## Installation

### Prerequisites

It is recommended to use the provided Docker image which can be [found on Quay](https://quay.io/helmpack/chart-testing/).
It comes with all necessary tools installed.

* [Helm](http://helm.sh)
* [Git](https://git-scm.com) (2.17.0 or later)
* [Yamllint](https://github.com/adrienverge/yamllint)
* [Yamale](https://github.com/23andMe/Yamale)
* [Kubectl](https://kubernetes.io/docs/reference/kubectl/overview/)

### Binary Distribution

Download the release distribution for your OS from the Releases page:

https://github.com/helm/chart-testing/releases

Unpack the `ct` binary, add it to your PATH, and you are good to go!

### Docker Image

A Docker image is available at `quay.io/helmpack/chart-testing` with list of
available tags [here](https://quay.io/repository/helmpack/chart-testing?tab=tags).

### From Source

To install from head with [Go](https://golang.org) 1.13 or higher:

```cli
go get github.com/helm/chart-testing/ct
```

This will put `ct` in `$(go env GOPATH)/bin`. You may need to add that directory to your `$PATH` as shown [here](https://golang.org/doc/code.html#GOPATH) if you encounter the error `ct: command not found` after installation.

## Usage

See documentation for individual commands:

* [ct](doc/ct.md)
* [ct install](doc/ct_install.md)
* [ct lint](doc/ct_lint.md)
* [ct lint-and-install](doc/ct_lint-and-install.md)
* [ct list-changed](doc/ct_list-changed.md)
* [ct version](doc/ct_version.md)


## Configuration

`ct` is a command-line application.
All command-line flags can also be set via environment variables or config file.
Environment variables must be prefixed with `CT_`.
Underscores must be used instead of hyphens.

CLI flags, environment variables, and a config file can be mixed.
The following order of precedence applies:

1. CLI flags
1. Environment variables
1. Config file

Note that linting requires config file for [yamllint](https://github.com/adrienverge/yamllint) and [yamale](https://github.com/23andMe/Yamale).
If not specified, these files are search in the current directory, `$HOME/.ct`, and `/etc/ct`, in that order.
Samples are provided in the [etc](etc) folder.

### Examples

The following example show various way of configuring the same thing:

#### CLI

    ct install --remote upstream --chart-dirs stable,incubator --build-id pr-42

#### Environment Variables

    export CT_REMOTE=upstream
    export CT_CHART_DIRS=stable,incubator
    export CT_BUILD_ID

    ct install

#### Config File

`config.yaml`:

```yaml
remote: upstream
chart-dirs:
  - stable
  - incubator
build-id: pr-42
```

#### Config Usage

    ct install --config config.yaml


`ct` supports any format [Viper](https://github.com/spf13/viper) can read, i. e. JSON, TOML, YAML, HCL, and Java properties files.

Notice that if no config file is specified, then `ct.yaml` (or any of the supported formats) is loaded from the current directory, `$HOME/.ct`, or `/etc/ct`, in that order, if found.


#### Using private chart repositories

When adding chart-repos you can specify additional arguments for the `helm repo add` command using `helm-repo-extra-args` on a per-repo basis.
This could for example be used to authenticate a private chart repository.

`config.yaml`:

```yaml
chart-repos:
  - incubator=https://incubator.io
  - basic-auth=https://private.com
  - ssl-repo=https://self-signed.ca
helm-repo-extra-args:
  - ssl-repo=--ca-file ./my-ca.crt
```

    ct install --config config.yaml --helm-repo-extra-args "basic-auth=--username user --password secret"

## Building from Source

`ct` is built using Go 1.12.4. Older versions may work but have not been tested.

`build.sh` is used to build and release the tool. It uses [Goreleaser](https://goreleaser.com/) under the covers.

Note: on MacOS you will need `GNU Coreutils readlink`.
You can install it with:

```console
brew install coreutils
```

Then add `gnubin` to your `$PATH`, with:

```console
echo 'export PATH="$(brew --prefix coreutils)/libexec/gnubin:$PATH"' >> ~/.bash_profile
bash --login
```

To use the build script:

```console
$ ./build.sh -h
Usage: build.sh <options>

Build ct using Goreleaser.

    -h, --help      Display help
    -d, --debug     Display verbose output and run Goreleaser with --debug
    -r, --release   Create a release using Goreleaser. This includes the creation
                    of a GitHub release and building and pushing the Docker image.
                    If this flag is not specified, Goreleaser is run with --snapshot
```

## Releasing

### Prepare Release

Before a release is created, versions have to be updated in the examples.
A pull request needs to be created for this, which should be merged right before the release is cut.
Here's a previous one for reference: https://github.com/helm/chart-testing/pull/89

### Create Release

CircleCI creates releases automatically when a new tag is pushed.
Tags are created using `tag.sh`.

```console
$ ./tag.sh -h
Usage: tag.sh <options>

Create and push a tag.

    -h, --help        Display help
    -d, --debug       Display verbose output
    -r, --remote      The name of the remote to push the tag to (default: upstream)
    -f, --force       Force an existing tag to be overwritten
    -t, --tag         The name of the tag to create
    -s, --skip-push   Skip pushing the tag
```

By default, the script assumes that `origin` points to your own fork and that you have a remote `upstream` that points to the upstream `chart-testing` repo.
Run the script specifying the version for the new release.

```console
./tag.sh --tag <release_version>
```

Versions must start with a lower-case `v`, e. g. `v2.5.0`.


## Supported versions

The previous MAJOR version will be supported for three months after each new MAJOR release.

Within this support window, pull requests for the previous MAJOR version should be made against the previous release branch.
For example, if the current MAJOR version is `v2`, the pull request base branch should be `release-v1`.

## Upgrading

When upgrading from `< v2.0.0` you will also need to change the usage in your scripts.
This is because, while the [v2.0.0](https://github.com/helm/chart-testing/releases/tag/v2.0.0) release has parity with `v1`, it was refactored from a bash library to Go so there are minor syntax differences.
Compare [v1 usage](https://github.com/helm/chart-testing/tree/release-v1#usage) with this (`v2`) version's README [usage](#usage) section above.