action.yml

name: 'Inject SSH Key'
description: 'Configures CI environment to use the private SSH key from a given secret'
inputs:
  private-key:
    description: 'Private SSH key to configure'
    required: true
  host-name:
    description: 'Hostname to configure in ~/.ssh/known_hosts, defaults to github.com'
    required: false
    default: 'github.com'
runs:
  using: "composite"
  steps:
    - name: write-ssh-key
      shell: bash
      run: |
        install -m 600 -D /dev/null ~/.ssh/id_rsa
        echo "${{ inputs.private-key }}" > ~/.ssh/id_rsa
    - name: add-to-know-hosts
      shell: bash
      run: |
        install -m 600 -D /dev/null ~/.ssh/known_hosts
        host='${{ inputs.host-name }}'
        hosts="$(dig +short "$host" | grep -v '\.$' | sed -z 's|\n|,|g')$host"
        echo "Adding keys for $hosts"
        ssh-keyscan -H "$hosts" > ~/.ssh/known_hosts
        (ssh-keygen -F "$host" > /dev/null && echo "$host registered") \
          || echo "Failed to register $host"

branding:
  icon: 'log-in'
  color: 'purple'