name: 'Attest SBOM'
description: 'Generate SBOM attestations for build artifacts'
author: 'GitHub'

inputs:
  path:
    required: false
    description: "A path to a directory on the filesystem to scan"
    default: "."

  format:
    required: false
    description: "The SBOM format to export"
    default: "spdx-json"

  github-token:
    description: >
      The GitHub token used to make authenticated API requests.
    default: ${{ github.token }}
    required: false
  subject-path:
    description: >
      Path to the artifact for which provenance will be generated. Must specify
      exactly one of "subject-path" or "subject-digest".
    required: false
  subject-digest:
    description: >
      Digest of the subject for which provenance will be generated. Must be in
      the form "algorithm:hex_digest" (e.g. "sha256:abc123..."). Must specify
      exactly one of "subject-path" or "subject-digest".
    required: false
  subject-name:
    description: >
      Subject name as it should appear in the provenance statement. Required
      unless "subject-path" is specified, in which case it will be inferred from
      the path.
  push-to-registry:
    description: >
      Whether to push the provenance statement to the image registry. Requires
      that the "subject-name" parameter specify the fully-qualified image name
      and that the "subject-digest" parameter be specified. Defaults to false.
    default: false
    required: false
  sbom-path:
    description: >
      Path to the SBOM file to generate sbom statement.
    required: false
    default: ''
outputs:
  bundle-path:
    description: 'The path to the file containing the attestation bundle(s).'
    value: ${{ steps.attest.outputs.bundle-path }}

runs:
  using: 'composite'
  steps:   
    - name: Generate random SBOM output file name
      if: ${{ inputs.sbom-path == '' }}
      run: echo "SBOM_FILENAME=${{ runner.temp }}/sbom_$(openssl rand -hex 6).json" >> $GITHUB_ENV
      shell: bash
    - name: SBOM format check
      if: ${{ inputs.sbom-path == '' }}
      run: |
        if [ "${{inputs.format}}" != "spdx-json" ] && [ "${{inputs.format}}" != "cyclonedx-json" ] && [ "${{inputs.format}}" != "spdx" ] && [ "${{inputs.format}}" != "cyclonedx" ] ]; then
          echo "Invalid SBOM format. Supported formats are spdx-json, cyclonedx-json, spdx, cyclonedx"
          exit 1
        fi
        echo "SBOM_FORMAT=${{inputs.format}}" >> $GITHUB_ENV
        if [ "${{inputs.format}}" == "spdx" ]; then
          echo "SBOM_FORMAT=spdx-json" >> $GITHUB_ENV
        elif [ "${{inputs.format}}" == "cyclonedx" ]; then
          echo "SBOM_FORMAT=cyclonedx-json" >> $GITHUB_ENV
        fi
      shell: bash
    - name: Generate SBOM
      if: ${{ inputs.sbom-path == '' }}
      uses: anchore/sbom-action@v0
      with:
        path: ${{inputs.path}}
        output-file: ${{env.SBOM_FILENAME}}
        format: ${{env.SBOM_FORMAT}}
        config: ${{inputs.config}}
    - uses: ./generate-sbom-statement
      id: generate-sbom-statement
      with:
        github-token: ${{ inputs.github-token }}
        subject-path: ${{ inputs.subject-path }}
        subject-digest: ${{ inputs.subject-digest }}
        subject-name: ${{ inputs.subject-name }}
        push-to-registry: ${{ inputs.push-to-registry }}
        sbom-path: ${{ inputs.sbom-path || env.SBOM_FILENAME }}
    - uses: actions/attest@main
      id: attest
      with:
        github-token: ${{ inputs.github-token }}
        subject-path: ${{ inputs.subject-path }}
        subject-digest: ${{ inputs.subject-digest }}
        subject-name: ${{ inputs.subject-name }}
        push-to-registry: ${{ inputs.push-to-registry }}
        predicate-type: ${{ steps.generate-sbom-statement.outputs.predicate-type }}
        predicate-path: ${{ steps.generate-sbom-statement.outputs.predicate-path }}