Simple usage of Welder

Imagine you need to run a single command within a container with a specific SDK (e.g. Java). Normally you would use Docker CLI to start it up and pass all the necessary arguments to integrate container's environment with local secrets and configurations:

docker run --rm -it \
   --volume=$HOME/.m2/repository:/root/.m2/repository \
   --volume=$HOME/.m2/settings.xml:/root/.m2/settings.xml:ro \
   --volume=$HOME/.m2/settings-security.xml:/root/.m2/settings-security.xml:ro \
   --volume=$HOME/.git:/root/.git:ro \
   --volume=$HOME/.ssh:/root/.ssh:ro \
   --volume=$(pwd):/root/src \
   --workdir=/root/src \
   maven:3.6-openjdk-11 \
    clean install

The same thing could be done with Welder in the following way (welder.yaml descriptor):

schemaVersion: 1.8.0
tasks:
  build:
    image: maven:3.6-openjdk-11
    volumes:
      - ~/.m2/repository:${container:home}/.m2/repository
      - ~/.m2/settings.xml:${container:home}/.m2/settings.xml:ro
      - ~/.m2/settings-security.xml:${container:home}/.m2/settings-security.xml:ro
      - ~/.git:${container:home}/.git:ro
      - ~/.ssh:${container:home}/.ssh:ro
    script:
      - mvn clean install

Then you can run it by running the following command:

welder run build

You can declare different tasks and invoke them with a simple command if necessary. The declared tasks can be referenced from the build lifecycle of a project, e.g.:

schemaVersion: 1.8.0
modules:
  - name: backend
    build:
      steps:
        - task: build
tasks:
  build:
    image: maven:3.6-openjdk-11
    script:
      - mvn clean install

When you invoke welder make it'll run the build task. It is clear that you can run multiple tasks as steps within your build definition. Each task can use different image and script.

For a more detailed description of the build lifecycle, please see build and test service.