Pass Git Branch Name into Concourse task

Question

I'm looking for a way to get a git branch name to use in a script. The head_name gives me the name of the branch I'm looking for, but I'm unsure how to pass that parameter into a task.

Answer 1

You don't have direct access to the metadata from the get container.

The git resource performs a git clone into the container, so you have access to the data. If your task image has the git CLI, I would just run git branch --show-current (from https://stackoverflow.com/a/6245587/4462517).

If your task image does not have git and you can't/don't want to install it, you could add a task like this before your current task:

- task: get-git-branch
  config:
    platform: linux
    image_resource:
      type: registry-image
      source:
        repository: concourse/git-resource
    inputs:
    - name: source # or whatever your git resource is named
    outputs:
    - name: branch-info
    run:
      path: bash
      args:
      - -c
      - |
        cd source
        git branch --show-current > ../branch-info/current-branch

From there, you could add the branch-info output as an input to your task, and read the contents of branch-info/current-branch to use it.