python script does not run with sleep in loop

[Katafalkas]

Hey,

I am trying to run a python script under pm2. It would be like cron but would run more often.

import time

def main():
  while True:
    print time.sleep
    print "bar"
    time.sleep(1)

if __name__ == '__main__':
  print "Hello Script"
  main()

The problem is that for some reason if there is a sleep in while loop, or for loop - script does not even start. if I comment the time.sleep(1) - script runs fine:

# pm2 logs
...
[test.py-24 (out)] bar
[test.py-24 (out)] <built-in function sleep>
...

If I run script regulary with # python test.py the sleep works as intended.

Any ideas ?

[soyuka]

How are you running the python script?
Try pm2 start -x --interpreter=python test.py

[Katafalkas]

Hey. Sorry, forgot to mention. I start the script with pm2 start /root/test.py -x --interpreter python.
Tried with pm2 start -x --interpreter=python test.py - outcome was the same.

[jlagneau]

It should work without the interpreter option (since 7d3bd3f)

Try directly with pm2 start test.py.

There's already a test for an infinite loop in python in this commit : https://github.com/Unitech/PM2/blob/7d3bd3fabeabcfdf5c8b754f3f863c2cb1b01d46/test/fixtures/binary-py-file.py

I am trying to reproduce your bug but it works fine here.

[jlagneau]

My pm2 logs after I started your script:

...
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
[test.py-0 (out)] <built-in function sleep>
[test.py-0 (out)] bar
...

% pm2 --version
0.12.1
% python --version
Python 2.7.6

[Katafalkas]

Hey,
still not working:

# pm2 start test2.py
[PM2] Process test2.py launched
┌──────────┬────┬──────┬──────┬────────┬───────────┬────────┬─────────────┬─────────────┐
│ App name │ id │ mode │ PID  │ status │ restarted │ uptime │      memory │    watching │
├──────────┼────┼──────┼──────┼────────┼───────────┼────────┼─────────────┼─────────────┤
│  test.py │ 30 │ fork │ 9628 │ online │         0 │ 0s     │  4.770 MB   │ unactivated │
└──────────┴────┴──────┴──────┴────────┴───────────┴────────┴─────────────┴─────────────┘

# pm2 logs
[PM2] Starting execution sequence in -fork mode- for app name:test1.py id:30
[PM2] App name:test.py id:30 online

and there are no print statements.

pm2 --version
0.11.1

Gonna try to upgrade to new version of pm2

[Katafalkas]

Tried with pm2 12.1 - still no changes. Logs are empty.

root@api:~# pm2 --version
0.12.1
root@api:~# python --version
Python 2.7.6
root@api:~# pm2 start test.py 
[PM2] Process test.py launched
┌──────────┬────┬──────┬──────┬────────┬───────────┬────────┬────────────┬──────────┐
│ App name │ id │ mode │ PID  │ status │ restarted │ uptime │     memory │ watching │
├──────────┼────┼──────┼──────┼────────┼───────────┼────────┼────────────┼──────────┤
│ test.py  │ 4  │ fork │ 9967 │ online │         0 │ 0s     │ 4.773 MB   │ disabled │
└──────────┴────┴──────┴──────┴────────┴───────────┴────────┴────────────┴──────────┘
 Use `pm2 info <id|name>` to get more details about an app
root@api:~# pm2 logs
########### Starting streaming logs for [all] process
[PM2] Starting execution sequence in -fork mode- for app name:test.py id:4
[PM2] App name:test.py id:4 online

[Katafalkas]

So i came back and turned logs back on - seems that the script is actually working, but the logs are really lagging. After I start the script the logs are empty for quite few minutes and the pm2 just dumps a bunch of logs into the log file.

[soyuka]

Might be #822 (comment) related?

[Katafalkas]

Could be. I ll keep an eye on it.

[soyuka]

Closing for now ;)