Document monorepo mode in readme

README.md

@@ -20,6 +20,8 @@ into your CI workflows.**
  branches, and creates/updates a PR comment which summarizes the impact of the
  changes.
  - ⚠️ Also annotates changed files with new issues encountered by Code PushUp.
+- 🏢 Supports monorepo setups - runs per project and summarizes comparisons in a
+ single PR comment.
 
 ## Workflow example
 
@@ -55,16 +57,19 @@ jobs:
 
 The action may be customized using the following optional inputs:
 
-| Name | Description | Default |
-| :------------ | :----------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------- |
-| `token` | GitHub token for authorizing GitHub API requests | `${{ github.token }}` |
-| `annotations` | Toggles if annotations should be created for relevant Code PushUp issues | `true` |
-| `artifacts` | Toggles if artifacts will we uploaded/downloaded | `true` |
-| `retention` | Artifact retention period in days | from repository settings |
-| `directory` | Directory in which `code-pushup` should run | `process.cwd()` |
-| `config` | Path to config file (`--config` option) | see [`@code-pushup/cli` docs](https://github.com/code-pushup/cli/tree/main/packages/cli#configuration) |
-| `silent` | Toggles if logs from Code PushUp CLI are printed | `false` |
-| `bin` | Command for executing Code PushUp CLI | `npx --no-install code-pushup` |
+| Name | Description | Default |
+| :------------ | :-------------------------------------------------------------------------------- | :----------------------------------------------------------------------------------------------------- |
+| `monorepo` | Enables [monorepo mode](#monorepo-mode) | `false` |
+| `projects` | Custom projects configuration for [monorepo mode](#monorepo-mode) | none |
+| `task` | Name of command to run Code PushUp per project in [monorepo mode](#monorepo-mode) | `code-pushup` |
+| `token` | GitHub token for authorizing GitHub API requests | `${{ github.token }}` |
+| `annotations` | Toggles if annotations should be created for relevant Code PushUp issues | `true` |
+| `artifacts` | Toggles if artifacts will we uploaded/downloaded | `true` |
+| `retention` | Artifact retention period in days | from repository settings |
+| `directory` | Directory in which `code-pushup` should run | `process.cwd()` |
+| `config` | Path to config file (`--config` option) | see [`@code-pushup/cli` docs](https://github.com/code-pushup/cli/tree/main/packages/cli#configuration) |
+| `silent` | Toggles if logs from Code PushUp CLI are printed | `false` |
+| `bin` | Command for executing Code PushUp CLI | `npx --no-install code-pushup` |
 
 For example, this will run `code-pushup` commands in a non-root folder and
 retain report artifacts for 30 days:
@@ -80,17 +85,68 @@ retain report artifacts for 30 days:
 
 Some outputs are set in case you want to add further steps to your workflow.
 
-| Name | Description |
-| :------------ | :---------------------------------------------------- |
-| `artifact-id` | ID of uploaded report artifact (N/A in monorepo mode) |
-| `comment-id` | ID of created/updated PR comment |
+| Name | Description  |
+| :------------ | :---------------------------------------------------------------------- |
+| `artifact-id` | ID of uploaded report artifact (N/A in [monorepo mode](#monorepo-mode)) |
+| `comment-id` | ID of created/updated PR comment  |
 
 Example of using step outputs:
 
 ```yml
 - uses: code-pushup/github-action@v0
  id: code-pushup
-  run: |
+- run: |
  echo "Comment ID is ${{ steps.code-pushup.outputs.comment-id }}"
  echo "Artifact ID is ${{ steps.code-pushup.outputs.artifact-id }}"
 ```
+
+## Monorepo mode
+
+By default, the GitHub Action assumes your repository is a standalone project.
+But it also supports monorepo setups where reports are collected and compared
+individually per project. All project comparisons are then combined into a
+single PR comment.
+
+Use the `monorepo` input to active monorepo mode:
+
+```yml
+- uses: code-pushup/github-action@v0
+ with:
+ monorepo: true
+```
+
+The GitHub Action will try to detect which monorepo tool you're using from the
+file system. The following tools are supported out of the box:
+
+- [Nx](https://nx.dev/)
+- [Turborepo](https://turbo.build/)
+- [Yarn workspaces](https://classic.yarnpkg.com/lang/en/docs/workspaces/)
+- [PNPM workspace](https://pnpm.io/workspaces)
+- [npm workspaces](https://docs.npmjs.com/cli/using-npm/workspaces)
+
+If you're using one of these tools, you can also skip auto-detection by setting
+`monorepo` input to `nx`, `turbo`, `yarn`, `pnpm` or `npm`.
+
+If none of these tools are detected, then the fallback is to run Code PushUp in
+all folders which have a `package.json` file. If that's not what you want, then
+you can also configure folder patterns using the optional `projects` input
+(comma-separated globs):
+
+```yml
+- uses: code-pushup/github-action@v0
+ with:
+ monorepo: true
+ projects: 'frontend, backend/*'
+```
+
+Based on which monorepo tool is used, Code PushUp CLI commands will be executed
+using a `package.json` script, Nx target, Turbo task, or binary executable (as
+fallback). By default, these are expected to be called `code-pushup`, but you
+can override the name using the optional `task` input:
+
+```yml
+- uses: code-pushup/github-action@v0
+ with:
+ monorepo: nx
+ task: analyze # custom Nx target
+```