concurrently: SIGINT is sent twice when pressing Ctrl-C, causing dirty shutdown

Hi,

I have the same problem and investigated a little bit. By commenting out that line, I ended up with something working correctly, no double SIGINT, everything is cool.

It looks like spawn-command does not spawn the subprocess in detached mode, and it seems the defaults in concurrently are not setting detached options neither. Because if not, it’s perfectly normal to have the SIGINT sent twice, because it’s received by the subprocess, and then resent with command.kill(signal) a second time.

Running into this problem myself, here’s a bit from my package.json:

  "scripts": {
    "build": "tsc",
    "build:watch": "tsc -w",
    "format": "prettier --write src/**/*.ts",
    "emulate": "firebase emulators:start --import=./emulator-data --export-on-exit",
    "serve": "concurrently 'npm run build:watch' 'npm run emulate'"
  },

If I run npm run serve and then press Ctrl+C the Firebase emulators see double SIGINT signals and shutdown without exporting data.

I think this may be due to Concurrently’s use of tree-kill to terminate individual processes. For example, if you send a SIGINT signal to a Docker Compose, it will handle terminating its subprocesses on its own; there’s no need for Concurrently to know or care that the process has subprocesses (although I’m sure that’s not always the case). But I think having the option to override this behaviour with simply sending the signal to each of the original processes might solve this issue.

I wanted to verify this by writing a minimal wrapper for the Concurrently API and passing (pid, signal) => process.kill(pid, signal) as the kill option; but it doesn’t quite seem to work as it should - there’s no output at all (even when I pass outputStream: process.stdout in the options), and the script seems to terminate immediately when I hit Ctrl+C, as opposed to waiting for the child processes to exit, like the CLI does; so I don’t really know how to verify this.

@jasonkylefrank kind of - i am running the emulators outside of concurrently but my servers are still running via concurrently

as for windows - i don’t use windows so idk lol

@gustavohenke I moved from concurrently to Docker Containers last year, and that removed the dirty shutdown issue for me.

hi there! I’m experiencing this issue too if I try to run firebase directly as concurrently command.

However, if my firebase command is wrapped with yarn script command in package.json, the issue is not reproduced. Looks like yarn already does some protection of double sent signals.

I can’t use full command in scripts since I construct firebase command args on the fly. So I did an alias like that:

// package.json

"scripts": {
  "firebase:emulators": "firebase emulators:start",
}

and then call the command via concurrently like that:

yarn firebase:emulators --only ... <here are my dynamic args>

for me this is a legit workaround, hope it helps someone else

I have not been able to create a small test case that consistently shows this error, but I have discovered that skipping the pubsub emulator makes the error go away. For example, using this:

firebase emulators:start --only firestore,database,functions,hosting,pubsub

will send SIGINT twice when quitting concurrently, while this:

firebase emulators:start --only firestore,database,functions,hosting

will not.

The positive case comes here.

If I launch: concurrently -> Docker -> Firebase CLI (which I do in a web app project, all the time), the double Ctrl-C occurs.

• It’s always connected to using Docker
• diving into the container and launching it manually from there (no concurrently involved) doesn’t recreate the error

> concurrently --kill-others "$(docker-run-cmd) firebase emulators:start --project=demo-2"

Launching Docker... 🐳



[0] ⚠  emulators: You are not currently authenticated so some features may not work correctly. Please run firebase login to authenticate the CLI.
[0] i  emulators: Starting emulators: auth, functions, firestore
[0] i  emulators: Detected demo project ID "demo-2", emulated services will use a demo configuration and attempts to access non-emulated services for this project will fail.
[0] ⚠  Your requested "node" version "14 || ^16" doesn't match your global version "16"
[0] ⚠  functions: You are not signed in to the Firebase CLI. If you have authorized this machine using gcloud application-default credentials those may be discovered and used to access production services.
[0] i  firestore: Firestore Emulator logging to firestore-debug.log
[0] i  ui: Emulator UI logging to ui-debug.log
[0] i  functions: Watching "/work/functions" for Cloud Functions...
[0] ✔  functions[us-central1-cloudLoggingProxy_v0]: http function initialized (http://0.0.0.0:5002/demo-2/us-central1/cloudLoggingProxy_v0).
[0] ✔  functions[us-central1-userInfoShadow_2]: firestore function initialized.
[0] 
[0] ┌─────────────────────────────────────────────────────────────┐
[0] │ ✔  All emulators ready! It is now safe to connect your app. │
[0] │ i  View Emulator UI at http://0.0.0.0:4000                  │
[0] └─────────────────────────────────────────────────────────────┘
[0] 
[0] ┌────────────────┬──────────────┬───────────────────────────────┐
[0] │ Emulator       │ Host:Port    │ View in Emulator UI           │
[0] ├────────────────┼──────────────┼───────────────────────────────┤
[0] │ Authentication │ 0.0.0.0:9100 │ http://0.0.0.0:4000/auth      │
[0] ├────────────────┼──────────────┼───────────────────────────────┤
[0] │ Functions      │ 0.0.0.0:5002 │ http://0.0.0.0:4000/functions │
[0] ├────────────────┼──────────────┼───────────────────────────────┤
[0] │ Firestore      │ 0.0.0.0:6767 │ http://0.0.0.0:4000/firestore │
[0] └────────────────┴──────────────┴───────────────────────────────┘
[0]   Emulator Hub running at localhost:4400
[0]   Other reserved ports: 4500
[0] 
[0] Issues? Report them at https://github.com/firebase/firebase-tools/issues and attach the *-debug.log files.
[0]  
^C[0]  
[0] i  emulators: Received SIGINT (Ctrl-C) for the first time. Starting a clean shutdown.
[0] i  emulators: Please wait for a clean shutdown or send the SIGINT (Ctrl-C) signal again to stop right now.
[0] i  emulators: Shutting down emulators.
[0] i  ui: Stopping Emulator UI
[0] ⚠  Emulator UI has exited upon receiving signal: SIGINT
[0] i  functions: Stopping Functions Emulator
[0] i  firestore: Stopping Firestore Emulator
[0]  
[0] ⚠  emulators: Received SIGINT (Ctrl-C) 2 times. You have forced the Emulator Suite to exit without waiting for 1 subprocess to finish. These processes may still be running on your machine: 
[0] 
[0] ┌────────────────────┬──────────────┬─────┐
[0] │ Emulator           │ Host:Port    │ PID │
[0] ├────────────────────┼──────────────┼─────┤
[0] │ Firestore Emulator │ 0.0.0.0:6767 │ 30  │
[0] └────────────────────┴──────────────┴─────┘
[0] 
[0] To force them to exit run:
[0] 
[0] kill 30
[0] 
[0] docker run --rm --sig-proxy=true -v /Users/asko/Git/GroundLevel-firebase-es/packages/backend:/work -w /work -p 6767:6767 -p 5002:5002 -p 9100:9100 -p 4000:4000 firebase-ci-builder:9.12.1-node16-npm7 firebase emulators:start --project=demo-2 exited with code 0

Note: This is just my 2c. I am not really troubled by this error message, since if running things under Docker, things get cleaned up, anyhow.