Helm Maven Plugin

A Maven plugin that makes Maven properties available in your Helm Charts. It can be used to automatically package your Helm Chart, render it and upload it to a Helm repository like ChartMuseum.

Usage

Add the following to your pom.xml

<build>
  <plugins>
    ...
    <plugin>
      <groupId>com.deviceinsight.helm</groupId>
      <artifactId>helm-maven-plugin</artifactId>
      <version>2.10.0</version>
      <configuration>
        <chartName>my-chart</chartName>
        <chartRepoUrl>https://charts.helm.sh/stable</chartRepoUrl>
        <helmVersion>3.5.2</helmVersion>
        <strictLint>true</strictLint>
        <valuesFile>src/test/helm/my-chart/values.yaml</valuesFile>
      </configuration>
      <executions>
        <execution>
          <goals>
            <goal>package</goal>
            <goal>lint</goal>
            <goal>template</goal>
            <goal>deploy</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

In the same Maven module, put your helm charts into src/main/helm/<chartName>. In the Chart.yaml, you can use the ${artifactId}, ${project.version}, and ${project.name} Maven placeholders. You can also use Maven properties.

An example for a Chart.yaml is:

apiVersion: v1
description: A Helm chart installing Rubicon
name: ${artifactId}
version: ${project.version}
home: https://gitlab.device-insight.com/deviceinsight/rubicon
maintainers:
  - name: Device Insight
    url: https://www.device-insight.com

You probably also will adjust the templates/deployment.yaml so that the correct docker image is used. An example snippet:

[...]
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}/rubicon:${project.version}"
[...]

Configuration

Property	Default	Description
chartName	The Maven artifactId	The name of the chart
chartVersion	${project.model.version}	The version of the chart
chartRepoUrl	null	The URL of the Chart repository where dependencies are required from and where charts should be published to
incubatorRepoUrl	https://charts.helm.sh/incubator	The URL to the incubator Chart repository
addIncubatorRepo	true	Whether the repository defined in incubatorRepoUrl should be added when running the package goal
chartPublishUrl	${chartRepoUrl}/api/charts	The URL that will be used for publishing the chart. The default value will work if chartRepoUrl refers to a ChartMuseum.
chartPublishMethod	"POST"	The HTTP method that will be used for publishing requests
chartDeleteUrl	${chartRepoUrl}/api/charts/${chartName}/${chartVersion}	The URL that will be used for deleting a previous version of the chart. This is used for updating SNAPSHOT versions. The default value will work if chartRepoUrl refers to a ChartMuseum.
chartRepoUsername	None	The username for basic authentication against the chart repo
chartRepoPassword	None	The password for basic authentication against the chart repo
chartFolder	"src/main/helm/<chartName>"	The location of the chart files (e.g. Chart.yaml).
skipSnapshots	true	If true, SNAPSHOT versions will be built, but not deployed.
helmGroupId	"com.deviceinsight.helm"	The helm binary groupId
helmArtifactId	"helm"	The helm binary artifactId
helmVersion	None	The helm binary version. (Make sure to use a recent helm binary version that doesn’t use the old Helm Chart repositories from https://kubernetes-charts.storage.googleapis.com, >= 3.4.0 or >= 2.17.0 if you are still using Helm 2)
helmDownloadUrl	"https://get.helm.sh/"	The URL where the helm binary is downloaded from.
helm.skip	false	If true, execution will be skipped entirely
stableRepoUrl	"https://charts.helm.sh/stable"	For helm 2.x: Can be used to overwrite the default URL for stable repository during helm init
strictLint	false	If true, linting fails on warnings (see: Lint)
valuesFile	None	values file that should be used for goals Lint, Template
outputFile	target/test-classes/helm.yaml	output file for template goal
deployAtEnd	false	If true, the helm chart is deployed at the end of a multi-module Maven build. This option does not make sense for single-module Maven projects.

Goals

Package

Goal packages a chart directory into a chart archive using the helm package command.

Deploy

Goal publishes the packaged chart in the configured chart repository.

Lint

Goal examines a chart for possible issues using the helm lint command.

• A values file can be provided via parameter valueFile

• Strict linting can be configured via parameter strictLint

Template

goal locally renders templates using the helm template command.

• A values file can be provided via parameter valueFile

• An output file can be provided via parameter outputFile

Example

To use the deployAtEnd functionality it’s mandatory to put the Helm Maven Plugin configuration in the parent pom.

<build>
  <plugins>
    ...
    <plugin>
      <groupId>com.deviceinsight.helm</groupId>
      <artifactId>helm-maven-plugin</artifactId>
      <version>2.10.0</version>
      <configuration>
        <chartName>my-chart</chartName>
        <chartRepoUrl>https://charts.helm.sh/stable</chartRepoUrl>
        <helmVersion>3.5.2</helmVersion>
        <strictLint>true</strictLint>
        <valuesFile>src/test/helm/my-chart/values.yaml</valuesFile>
        <deployAtEnd>true</deployAtEnd>
      </configuration>
      <executions>
        <execution>
          <goals>
            <goal>package</goal>
            <goal>lint</goal>
            <goal>template</goal>
            <goal>deploy</goal>
          </goals>
        </execution>
      </executions>
    </plugin>
  </plugins>
</build>

Troubleshooting

1. Problem

   The following error message is a common source of trouble, lately:

   [ERROR] Output: Error: error initializing: Looks like "https://kubernetes-charts.storage.googleapis.com" is not a valid chart repository or cannot be reached: Failed to fetch https://kubernetes-charts.storage.googleapis.com/index.yaml : 403 Forbidden
   
   ...
   
   [ERROR] Failed to execute goal com.deviceinsight.helm:helm-maven-plugin:2.10.0:package (default) on project my-project: Error creating helm chart: When executing '/home/user/.m2/repository/com/deviceinsight/helm/helm/2.16.2/helm-2.16.2-linux-amd64.binary init --client-only' got result code '1' -> [Help 1]

   Solution

   This is likely due to an old version of helm itself. Make sure to configure <helmVersion> to a version >= 3.4.0 or, if you are still using Helm 2, a version >= 2.17.0 (background information).

2. Problem

   The following error message appears if you use an old version of helm-maven-plugin:

   [ERROR] Output: Error: error initializing: Looks like "https://kubernetes-charts-incubator.storage.googleapis.com" is not a valid chart repository or cannot be reached: Failed to fetch https://kubernetes-charts-incubator.storage.googleapis.com/index.yaml : 403 Forbidden

   Solution

   This can be solved by upgrading helm-maven-plugin itself to version 2.7.0 or later (#67).

Releasing

Creating a new release involves the following steps:

1. ./mvnw gitflow:release-start gitflow:release-finish

2. git push origin master

3. git push --tags

4. git push origin develop

In order to deploy the release to Maven Central, you need to create an account at https://issues.sonatype.org and configure your account in ~/.m2/settings.xml:

<settings>
  <servers>
    <server>
      <id>ossrh</id>
      <username>your-jira-id</username>
      <password>your-jira-pwd</password>
    </server>
  </servers>
</settings>

The account also needs access to the project on Maven Central. This can be requested by another project member.

Then check out the release you want to deploy (git checkout x.y.z) and run ./mvnw deploy -Prelease.