Restart a workspace application that has only a start script when the checkout changes

[csandanov]

In a development workspace, a Node.js application whose package has only a start script was started once. After a change to the code you had to restart the container to see it.

workspace-node start now watches the checkout for such a package: when a file changes, it stops the application and starts it again, in the same container.

Behavior

• A package with a dev script is run as before: a dev script watches the files itself.
• A package with only a start script is run under the watcher. Files are polled every WORKSPACE_POLL_INTERVAL milliseconds (1000 by default), because file events don't reach a shared volume.
• Not watched: node_modules, .git, .wodby-workspace, .pnpm-store, .next, dist, build and coverage.
• The script's processes run in a session of their own, so stopping reaches the application the package manager started.
• An application that ends by itself still ends the container with its exit code. Stopping the container stops the application at once; one that ignores the signal is killed after ten seconds.
• WORKSPACE_NODE_WATCH=0 turns the watcher off, and WORKSPACE_NODE_COMMAND is run as it is.

Validation

• tests/workspace-reload.sh, which tests/run.sh already runs for development images, has new cases. Run against wodby/node:24-dev-r5 with this script: the Vite and Next.js cases still pass; for a start script a second container's edit was served by the same container with one application process left, the container stopped in under ten seconds with exit code 143, an application that exited took the container with it, and neither WORKSPACE_NODE_WATCH=0 nor a dev script got the watcher.
• tests/workspace-runtime.sh passes in the same image.
• Tried with npm only, not with pnpm or yarn, and not on a multi-node cluster with a network volume.