Goals

Make sidecar task useful for running functional tests or other tasks that depend on shared services to be ran and cleaned up.

Non-goals

No response

Background

Currently, the sidecar tasks become persistent even if the task that depends on them is not persistent. And this makes sense in the original example of running webapp together with dev server.

But there is another usecase that is hard to solve cleanly with turborepo - starting and cleaning up services for specific task. While it is possbile with package tasks on package level: start service && run task && end service this is not possible on workspace level - start service -> run tasks in different packages -> stop service.

In my example, I want to start a DB, run functional tests in different packages, and then stop the DB when all tests finish. With current sidecar task implementation, I can almost define it and everything will start correctly, but when tests finish, the DB task is not stopped.

"test-functest": {
    "dependsOn": ["build", "ensure-functest-db"],
    "with": ["run-functest-db"],
    "cache": false
}

If the sidecar task would be stopped together with it would allow solving these kinds of cases in a really clean way. While it would be possible to set this up outside of turbo, it would not use the dependencies and change detection logic of turbo and for example, if none of the services or tests change, we would still start db.

Proposal

If all tasks dependent on a sidecar task stop, stop the sidecar task. Just like in a case when tasks exit with error. It should not work against original usecase for persistent tasks, but would allow other usecases.