local_resource should have a way to expose stdin

[nicks]

Repro steps:

1. Checkout tilt
2. Add this Tiltfile

local_resource('web', serve_cmd='cd web && yarn run start')

Expected behavior:

We should start up the tilt webpack server on 3000

Actual behavior:

The tilt webpack server dies with exit code 0 immediately

The problem:

Webpack exits immediately if no stdin is attached to the process

The workaround:

Rewrite the Tiltfile like this:

local_resource('web', serve_cmd='cd web && tail -f /dev/null | yarn run start')

which creates a "dumb" stdin that webpack can pull from forever

Possible solutions:

Most orchestration systems have an stdin parameter so you can specify stdin
https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#container-v1-core

[emschwartz]

Just ran into this issue trying to get Tilt to run the webpack dev server. In case anyone else searches for the error, it prints Server exited with exit code 0. Adding ail -f /dev/null | yarn start resolved the issue.

[lizzthabet]

@nicks, does #5641 solve this issue? i'm able to run the tilt webpack dev server without any problems.

[nicks]

@lizzthabet nope! that's just for local() in the tiltfile.

i wouldn't be surprised if webpack got fixed to handle this mode, but there are still lots of tools that don't handle stdin correctly.