Pm2: Python processes are left behind after kill

[saroka]

Hey people!

I'm running both Node.JS and Python scripts. When PM2 receives a kill interruption (not by $ pm2 kill), it successfully terminates all node processes, but leaves python processes behind, which causes duplicates when resurrecting PM2.

Do you have any ideas on this?

Btw, thanks for the awesome work 👍

Steps to reproduce

Create files script.py, script.js, ecosystem.config.js

script.py

import time

if __name__ == "__main__":
  while 1:
    print 'Script.py: alive'
    time.sleep(1)

script.js

setInterval(function() {
  console.log('Script.js: alive')
}, 1000);
````

*ecosystem.config.js*
```js
module.exports = {
  apps : [
    {
      name      : "py-script",
      script    : "script.py"
    },
    {
      name      : "js-script",
      script    : "script.js"
    }
  ]
}

Execute commands:

pm2 start ecosystem.config.js # start python and node apps

ps -ef |grep '[s]cript.py' # verify that script.py is running and its PID
ps -ef |grep '[s]cript.js' # verify that script.js is running and its PID

kill `cat ~/.pm2/pm2.pid` # kill PM2

ps -ef |grep '[s]cript.py' # script.py is still running
ps -ef |grep '[s]cript.js' # script.js is not running

Software versions used

OS         : Ubuntu 14.04
node.js    : 4.6.1
python    : 2.7.6
PM2        : 2.1.5

PM2 Log output

2016-11-18 12:26:51: Starting execution sequence in -fork mode- for app name:py-script id:0
2016-11-18 12:26:51: Starting execution sequence in -fork mode- for app name:js-script id:1
2016-11-18 12:26:51: App name:py-script id:0 online
2016-11-18 12:26:51: App name:js-script id:1 online
2016-11-18 12:26:58: pm2 has been killed by signal, dumping process list before exit...
2016-11-18 12:26:58: [PM2] Exited peacefully

[soyuka]

Do you see the same behavior by using pm2 kill? There might be a missing signal handler there.

[saroka]

No! All processes are killed.

PM2 log output:

2016-11-18 12:55:10: Starting execution sequence in -fork mode- for app name:py-script id:0
2016-11-18 12:55:10: Starting execution sequence in -fork mode- for app name:js-script id:1
2016-11-18 12:55:10: App name:py-script id:0 online
2016-11-18 12:55:10: App name:js-script id:1 online
2016-11-18 12:55:23: Stopping app:py-script id:0
2016-11-18 12:55:23: Stopping app:js-script id:1
2016-11-18 12:55:23: App [py-script] with id [0] and pid [10846], exited with code [1] via signal [SIGINT]
2016-11-18 12:55:23: [HandleExit] PM2 is being killed, stopping restart procedure...
2016-11-18 12:55:23: App [js-script] with id [1] and pid [10847], exited with code [0] via signal [SIGINT]
2016-11-18 12:55:23: [HandleExit] PM2 is being killed, stopping restart procedure...
2016-11-18 12:55:23: pid=10846 msg=process killed
2016-11-18 12:55:23: pid=10847 msg=process killed
2016-11-18 12:55:23: ===============================================================================
2016-11-18 12:55:23: --- Stopping PM2 --------------------------------------------------------------
2016-11-18 12:55:23: Time                 : Fri Nov 18 2016 12:55:23 GMT-0200 (BRST)
2016-11-18 12:55:23: ===============================================================================
2016-11-18 12:55:23: RPC closed
2016-11-18 12:55:23: PUB closed
2016-11-18 12:55:23: PM2 successfully stopped

[soyuka]

Hmm, weird

https://github.com/Unitech/pm2/blob/master/lib/Daemon.js#L251

the default signal for kill should be TERM which should be handled...

[soyuka]

2013 related?

[Unitech]

saroka thanks for the precise report it's been helpful to find the bug.

The fix is already available on the development branch:

$ npm install Unitech/pm2#development
$ pm2 update

[saroka]

Yeah! That fixed the issue 😺

Thank you!

[Unitech]

available in current pm2 version (2.1.6)