Python daemon library import error

Question

I get error with this script:

#!/usr/bin/env python

import sys, time, daemon

class MyDaemon(Daemon):
    def run(self):
        while True:
            time.sleep(1)

if __name__ == "__main__":
    daemon = MyDaemon('/tmp/daemon-example.pid')
    if len(sys.argv) == 2:
        if 'start' == sys.argv[1]:
            daemon.start()
        elif 'stop' == sys.argv[1]:
            daemon.stop()
        elif 'restart' == sys.argv[1]:
            daemon.restart()
        else:
            print("Unknown command")
            sys.exit(2)
        sys.exit(0)
    else:
        print("usage: %s start|stop|restart" % sys.argv[0])
        sys.exit(2)

It yields the following error:

Traceback (most recent call last):
  File "dtest2.py", line 5, in <module>
    class MyDaemon(Daemon):
NameError: name 'Daemon' is not defined

What am I doing wrong? I have installed daemon with 'sudo pip install daemon'.

UPDATE: following the advice from @DeepSpace I have changed the code to:

#!/usr/bin/env python

import sys, time, daemon

class MyDaemon(daemon.Daemon):
    def run(self):
        while True:
            time.sleep(1)

if __name__ == "__main__":
    daemon = MyDaemon('/tmp/daemon-example.pid')
    if len(sys.argv) == 2:
        if 'start' == sys.argv[1]:
            daemon.start()
        elif 'stop' == sys.argv[1]:
            daemon.stop()
        elif 'restart' == sys.argv[1]:
            daemon.restart()
        else:
            print("Unknown command")
            sys.exit(2)
        sys.exit(0)
    else:
        print("usage: %s start|stop|restart" % sys.argv[0])
        sys.exit(2)

...and it yields a different error

Traceback (most recent call last):
  File "dtest.py", line 3, in <module>
    import sys, time, daemon
  File "/usr/local/lib/python3.6/site-packages/daemon.py", line 70
    os.umask(022)   # Don't allow others to write
               ^
SyntaxError: invalid token

Any suggestions?

Answer 1

import sys, time, daemon does not tell the interpreter where does the Daemon class come from.

Either change class MyDaemon(Daemon) to class MyDaemon(daemon.Daemon) ,

or change

import sys, time, daemon

to

import sys
import time
from daemon import Daemon

According to PEP8 each import should be on its own line anyway .