@dotcom-tool-kit/monorepo

Enables Tool Kit to run commands across monorepo workspace packages.

Installation

Install @dotcom-tool-kit/monorepo as a devDependency in your app:

``sh
npm install --save-dev @dotcom-tool-kit/monorepo
`

Add the plugin to your Tool Kit configuration:

`yaml
plugins:
- '@dotcom-tool-kit/monorepo'
`

Tool Kit monorepo workflows

Most monorepos won't actually need to use this plugin.

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Some common tooling, such as TypeScript and Jest, are already workspace-aware using configuration such as TypeScript's project references. You can run these at the root level of your monorepo across all packages instead of running them package-by-package via Tool Kit and this plugin.

In almost all cases that will work better; for example, running Jest separately in workspace packages will produce separate test summaries for each package, instead of one summary for all test suites across your monorepo.

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Where tooling isn't monorepo-aware itself, or you have tooling that you only want to run in a subset of your workspace packages, the @dotcom-tool-kit/monorepo plugin allows the root-level .toolkitrc.yml to run commands from workspace-package-level .toolkitrc.yml files.

With this plugin, each workspace package is an independent Tool Kit root, which installs separate plugins for its own use cases. For example, a monorepo with an api package which is deployed to AWS would install the @dotcom-tool-kit/containerised-app plugin as a dependency of the package, not at the root level, and would then include that plugin in the package .toolkitrc.yml.

The root-level .toolkitrc.yml can then use the WorkspaceCommand task to forward commands such as deploy:production to just the workspace packages that have that command defined (in this case, the api package).

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It's also possible to run package.json scripts in workspace packages using npm run --workspaces, and you can acheive a similar workflow by adding these commands as package.json scripts at the root level. Depending on your use case that may be preferable for your team or project, but be aware of these tradeoffs:

- If we find there are common monorepo use cases between multiple projects, we can extract the Tool Kit configuration for that into a plugin that can be shared between projects. We can't do that if you're using package.json scripts.
- Mixing between package.json scripts and Tool Kit tasks would require chaining them with shell syntax in the package.json script, which is harder to read and less maintainable than having all the configuration in .toolkitrc.yml, and has worse error-handling behaviour.
- Due to a limitation in this plugin, package.json scripts in workspace packages can't be managed by Tool Kit. Any Tool Kit tasks in workspace packages you'd want to run via npm run --workspaces would have to be manually maintained as package.json scripts, risking your scripts becoming out of sync with the Tool Kit tasks you expect to be running.

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- Hooks in workspace packages are not installed, so configuration files like package.json in workspace packages can't be managed by Tool Kit. If you have a use case for this, please contact the Platforms team.

Tasks

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Runs a Tool Kit command in all workspace packages that have that command. By default, runs the command that was used to run this task.

For example, imagine a monorepo with these .toolkitrc.yml files:

Running dotcom-tool-kit run:local at the root level will run the Node task in packages/api and the Webpack task in watch mode in packages/components; running dotcom-tool-kit build:local will run TypeScript in packages/client and Webpack in packages/components.

To run a particular command in the workspace instead of dynamically inferring the command from which was run at root level, set the command option for the task:

~~~yml
commands:
build:ci:
WorkspaceCommand:
command: build:local
~~~


#### Task options

| Property | Description | Type |
| :-------------- | :---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :------- |
| command | A specific command to run instead of the command that ran this task. | string |
| packageFilter | By default, the command will run in every workspace command that has that command assigned to a task. This option is a glob pattern to further filter the packages the command will run on. For example, if your workspace has packages in the plugins and lib folders, set packageFilter to plugins/* to only run only in the packages in plugins which have a command assigned to a task. | string` |

_All properties are optional._