Ts-node-dev: Doesn't kill child process

[timsuchanek]

A simple script like this:

import { spawn } from 'child_process'

const child = spawn('./bin.js')
child.stdout.on('data', data => {
  console.log(data.toString())
})

will not be killed properly and on every reload another child will be spawned.

Reproduction: https://github.com/timsuchanek/ts-node-dev-child

A couple of thoughts:

1. I just tried it out, it was already broken in node-dev.
2. I highly recommend removing the non-standard behavior of not exiting, as soon as you add a process.on('SIGTERM') -> It took us about 2 weeks to find that weird behavior out. https://github.com/fgnass/node-dev#graceful-restarts
3. I don't know if this is a limitation by design based on the require stuff, but it doesn't happen with nodemon.

tsc-watch uses this approach: listing the child processes and killing them.

We're heavily relying on this with Prisma and really like ts-node-dev so far, so if you need a PR for this or any help, let us know.

[wclr]

you mean child process of running process is not killed? btw try --tree-kill option (which is kind of experimental)

There is also a notion about using process.on('SIGTERM', () => process.exit()) in ts-node-dev docs

[timsuchanek]

Thanks, that's exactly what I meant! I'll try the --tree-kill out. In my testing the SIGTERM process.exit didn't kill the child process of the running process properly.

Optimally we don't have to add any process.on('SIGTERM') to keep our examples clean, as when people see that, they'll copy that stuff over into their production code.

[timsuchanek]

--tree-kill works perfectly 👍
So if you add it to the README, we can close this.
I would still consider rethinking this:
https://github.com/whitecolor/ts-node-dev/blob/24813393769d23da9e585c157b3375f594ecba5e/lib/wrap.js#L26
As there is already the IPC option.

[abhisekp]

@whitecolor I'm using the following options but it doesn't kill the process running the --inspect with --tree-kill

# npm run script
cross-env-shell DEBUG=app* ts-node-dev  --tree-kill --no-deps --clear --transpileOnly --debounce=5000 --watch=config --nolazy --inspect=9259 -- index.js

So when I end the process and try to start again, it throws the following error

$ npm run debug

> cross-env-shell DEBUG=app* ts-node-dev  --tree-kill --no-deps --clear --transpileOnly --debounce=5000 --watch=config --nolazy --inspect=9259 -- index.js

Using ts-node version 8.3.0, typescript version 3.6.2
Starting inspector on 127.0.0.1:9259 failed: address already in use
npm ERR! code ELIFECYCLE
npm ERR! errno 12
npm ERR! [email protected] debug: `cross-env-shell DEBUG=app* ts-node-dev  --tree-kill --no-deps --clear --transpileOnly --debounce=5000 --watch=config --nolazy --inspect=9259 -- index.js`
npm ERR! Exit status 12
npm ERR! 
npm ERR! Failed at the [email protected] debug script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/bigapp/.npm/_logs/2019-09-10T13_15_50_167Z-debug.log

---

So then, I've to list the processes and kill it manually

$ lsof -i :9259

COMMAND  PID   USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
node    3272 bigapp   23u  IPv4 732230      0t0  TCP localhost:9259 (LISTEN)

$  kill -9 3272

[wclr]

Need repro example if the problem persists.

[joemags-apps]

Solved with --exit-child