feat(release-please): add release-please action

.github/release-please-config.json

@@ -23,6 +23,10 @@
     "actions/semconv/pull-request": {
       "component": "semconv-pull-request",
       "initial-version": "0.0.1"
+    },
+    "actions/release-please": {
+      "component": "release-please",
+      "initial-version": "0.0.1"
     }
   },
   "plugins": [

.github/release-please-manifest.json

@@ -1,3 +1,4 @@
 {
-  "actions/semconv/pull-request": "0.0.1"
+  "actions/semconv/pull-request": "0.0.1",
+  "actions/release-please": "0.0.1"
 }

.github/workflows/release-please.yml

@@ -15,10 +15,11 @@ jobs:
       contents: write
       pull-requests: write
     steps:
-      # The PAT rather than github.token, so the release pull request and the
-      # tag it produces trigger the workflows that react to them.
-      - uses: googleapis/release-please-action@45996ed1f6d02564a971a2fa1b5860e934307cf7 # v5.0.0
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          persist-credentials: false
+
+      # The repository releases itself with the action it ships.
+      - uses: ./actions/release-please
         with:
           token: ${{ secrets.GH_PAT_RELEASE_PLEASE_ACTION }}
-          config-file: .github/release-please-config.json
-          manifest-file: .github/release-please-manifest.json

actions/release-please/README.md

@@ -0,0 +1,106 @@
+# release-please
+
+Cuts releases with [release-please][release-please] from the configuration
+every repository shares.
+
+## Usage
+
+```yaml
+name: Release Please
+
+on:
+  push:
+    branches: [main]
+
+permissions: {}
+
+jobs:
+  release-please:
+    name: Release Please
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - uses: actions/checkout@<full-sha>
+        with:
+          persist-credentials: false
+      - uses: TrogonStack/github-actions/actions/release-please@<full-sha>
+        with:
+          token: ${{ secrets.GH_PAT_RELEASE_PLEASE_ACTION }}
+```
+
+The token must be the organization's personal access token rather than
+`github.token`, because a tag pushed with `github.token` does not trigger the
+workflows that react to a release.
+
+## Configuration
+
+The configuration is a file in your repository, because release-please fetches
+it from the branch over the API rather than from the checkout. Where it lives
+is fixed:
+
+```
+.github/release-please-config.json
+.github/release-please-manifest.json
+```
+
+Those paths are not inputs. One location for every repository is the reason
+this action exists; a knob invites back the drift it was built to remove.
+
+Start a repository from this configuration and change only `packages`:
+
+```json
+{
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
+  "release-type": "simple",
+  "bump-minor-pre-major": true,
+  "bump-patch-for-minor-pre-major": true,
+  "include-component-in-tag": true,
+  "include-v-in-tag": true,
+  "tag-separator": "@",
+  "separate-pull-requests": true,
+  "changelog-sections": [
+    { "type": "feat", "section": "Features", "hidden": false },
+    { "type": "fix", "section": "Bug Fixes", "hidden": false }
+  ],
+  "packages": {
+    ".": { "component": "your-component", "initial-version": "0.0.1" }
+  },
+  "plugins": [{ "type": "sentence-case" }],
+  "draft": false,
+  "draft-pull-request": false,
+  "prerelease": false,
+  "signoff": "SHT Bot <61149376+sht-bot@users.noreply.github.com>"
+}
+```
+
+The matching manifest starts every package at the sentinel:
+
+```json
+{ ".": "0.0.0" }
+```
+
+`0.0.0` means "never released" to release-please, which is what makes it honour
+`initial-version`. Any other starting value is read as a real previous release
+and gets bumped instead, so the first tag skips the version you asked for.
+
+## Outputs
+
+`releases_created`, `paths_released`, `prs_created` and `prs` are the ones a
+monorepo reads. `release_created`, `tag_name`, `sha`, `major`, `minor`,
+`patch`, `html_url` and `upload_url` are set only when the repository releases
+a single package.
+
+Release-please also sets per path outputs named after the path itself. A
+composite action cannot forward a name it does not know in advance, so a
+monorepo that needs them should read the `paths_released` array instead.
+
+## Inputs
+
+| Input | Default | Description |
+| --- | --- | --- |
+| `token` | required | Opens the release pull request and pushes the tag. |
+
+[release-please]: https://github.com/googleapis/release-please

actions/release-please/action.yml

@@ -0,0 +1,64 @@
+name: Release Please
+description: >-
+  Cuts releases with release-please from the configuration every repository
+  shares.
+author: TrogonStack
+
+inputs:
+  token:
+    description: >-
+      Token used to open the release pull request and push the tag. A personal
+      access token rather than github.token, so the tag it produces triggers
+      the workflows that react to it.
+    required: true
+
+outputs:
+  releases_created:
+    description: Whether any release was created.
+    value: ${{ steps.release-please.outputs.releases_created }}
+  paths_released:
+    description: JSON array of the paths released, which is what a monorepo reads.
+    value: ${{ steps.release-please.outputs.paths_released }}
+  prs_created:
+    description: Whether any release pull request was created.
+    value: ${{ steps.release-please.outputs.prs_created }}
+  prs:
+    description: JSON array of the release pull requests opened or updated.
+    value: ${{ steps.release-please.outputs.prs }}
+  release_created:
+    description: Whether a release was created. Single package repositories only.
+    value: ${{ steps.release-please.outputs.release_created }}
+  tag_name:
+    description: The tag pushed. Single package repositories only.
+    value: ${{ steps.release-please.outputs.tag_name }}
+  sha:
+    description: The commit the release points at. Single package repositories only.
+    value: ${{ steps.release-please.outputs.sha }}
+  major:
+    description: Major version released. Single package repositories only.
+    value: ${{ steps.release-please.outputs.major }}
+  minor:
+    description: Minor version released. Single package repositories only.
+    value: ${{ steps.release-please.outputs.minor }}
+  patch:
+    description: Patch version released. Single package repositories only.
+    value: ${{ steps.release-please.outputs.patch }}
+  html_url:
+    description: URL of the release. Single package repositories only.
+    value: ${{ steps.release-please.outputs.html_url }}
+  upload_url:
+    description: Release asset upload URL. Single package repositories only.
+    value: ${{ steps.release-please.outputs.upload_url }}
+
+runs:
+  using: composite
+  steps:
+    - name: Release Please
+      id: release-please
+      uses: googleapis/release-please-action@45996ed1f6d02564a971a2fa1b5860e934307cf7 # v5.0.0
+      with:
+        token: ${{ inputs.token }}
+        # These paths are deliberately not inputs: one location for every
+        # repository is the reason this action exists.
+        config-file: .github/release-please-config.json
+        manifest-file: .github/release-please-manifest.json