GitHub Action that renders Nowline roadmap diagrams in CI. Two modes:

• File mode — render a single .nowline file to SVG or PNG.
• Markdown mode — scan markdown files for ```nowline fenced code blocks, render each one, and insert / refresh an image reference adjacent to the block.

The action is the answer for hosts that strip <script> tags (GitHub READMEs, GitHub issues, GitHub PRs, email, Slack, Discord, Confluence rich text). For pages that can run scripts, see the browser embed instead.

The action's contract is render only. It writes / refreshes output files and emits the list of changed paths via the changed-files output. Committing the result is the user's responsibility — chain a purpose-built commit action like stefanzweifel/git-auto-commit-action or peter-evans/create-pull-request right after this one. The composition examples below show both.

- uses: lolay/nowline-action@v0
  with:
      mode: file
      input: docs/roadmap.nowline
      output: docs/roadmap.svg

- uses: stefanzweifel/git-auto-commit-action@v5
  with:
      commit_message: 'render nowline diagrams [skip ci]'
      file_pattern: 'docs/roadmap.svg'

Then in README.md:

![Roadmap](docs/roadmap.svg)

- uses: lolay/nowline-action@v0
  with:
      mode: markdown
      files: '**/*.md'

- uses: stefanzweifel/git-auto-commit-action@v5
  with:
      commit_message: 'render nowline diagrams [skip ci]'
      file_pattern: '**/*.md .nowline/'

The action finds every ```nowline block, renders each to ./.nowline/<slug>.svg, and inserts an image reference below the block. Subsequent runs idempotently refresh the rendered image without duplicating the markdown.

- uses: lolay/nowline-action@v0
  with:
      mode: markdown
      files: '**/*.md'

- uses: peter-evans/create-pull-request@v6
  with:
      branch: render-nowline-diagrams
      commit-message: 'render nowline diagrams'
      title: 'Render Nowline diagrams'
      add-paths: |
          **/*.md
          .nowline/

- uses: lolay/nowline-action@v0
  with:
      mode: markdown
      files: '**/*.md'

- name: Fail if rendered output drifted from committed
  shell: bash
  run: |
      git diff --exit-code -- '**/*.md' .nowline/

1. Installs @nowline/cli@<cli-version> globally on the runner (skipped when the requested version is already on PATH).
2. Shells out to nowline <input> -o <output> -f <format> -t <theme> for each render.
3. (Markdown mode) parses each markdown file with remark, finds ```nowline fenced code blocks, and for each block:
   • Computes a stable slug from the block's source (12-char SHA-256, so identical content always produces the same output filename).
   • Renders the block via the CLI to <output-dir>/nowline-<slug>.svg.
   • Inserts (or refreshes) an HTML-comment-fenced image reference below the block. Idempotent across runs — the same input produces the same output and the same markdown.
4. Emits the list of files that were written via the changed-files output, ready to feed into the commit / PR action of your choice.

This action's source lives in the lolay/nowline monorepo at packages/nowline-action/. The lolay/nowline-action repo is a write-only Marketplace mirror — file issues and PRs against the monorepo, not the mirror.

Apache-2.0. See LICENSE.