action.yml

name: "Build and push nix-based contaienr image"
description: "Builds a nix-expression into a docker image, optionally pushing it to a registry."
branding:
  color: purple
  icon: gift
inputs:
  src:
    description: "The nix-expression to build that will result in a docker image"
    required: true
    default: "docker.nix"
  registry:
    description: "The docker registry to upload to, e.g. `registry.example.com`"
    required: false
  path:
    description: "The path on the registry to upload to, e.g. `/main-project/example-service`"
    required: false
  username:
    description: "Username to authenticate to registry with"
    required: false
  password:
    description: "Password to authenticate to registry with"
    required: false
  tag:
    description: "Tag to use for the uploaded image. If not given, determine automatically. `main` and `master` are always translated to the tag `latest`; otherwise versions"
    required: false
  nixpkgs:
    description: "Path to the version of nixpkgs used for the upload. Anything that can be used with the `-I` option of `nix-shell`. Default is the `21.11` tag of nixpkgs."
    required: false
    default: "https://github.com/NixOS/nixpkgs/archive/refs/tags/21.11.tar.gz"
runs:
  using: "composite"
  steps:
    - name: "Build the docker-image"
      shell: sh
      run: nix-build --out-link /tmp/nix-container-build ${{ inputs.src }}
    - name: "Upload image to registry"
      shell: sh
      run: nix-shell -I nixpkgs="${{ inputs.nixpkgs }}" -p skopeo --run "${{ github.action_path }}/upload.sh"
      env:
        REGISTRY: ${{ inputs.registry }}
        USERNAME: ${{ inputs.username }}
        PASSWORD: ${{ inputs.password }}
        REPO_PATH: ${{ inputs.path }}
        INPUT_TAG: ${{ inputs.tag }}
        GITHUB_REF: ${{ github.ref }}