Are these both reasonable ways to check on the status of pigpiod from within Python?

Question

I'm trying to check on the status of the pigpiod process from within a python script. These two methods both appear to work so far. Are there any significant advantages or disadvantages of one over the other? Are these likely to be reliable ways to do this?

import os, commands

def test_1():
    try:
        n = int(os.popen('pidof pigpiod').read().splitlines()[0])
    except:
        n = None
    return n

def test_2():
    try:
        n = int(commands.getstatusoutput('pidof pigpiod')[1])
    except:
        n = None
    return n

print "test 1: ", test_1()
print "test 2: ", test_2()

pigpiod is running:

test 1:  2038
test 2:  2038

pigpiod has been stopped:

test 1:  None
test 2:  None

Answer 1

Obviously both work, but I would however:

• avoid to use the os module, but use subprocess instead; specifically subprocess.run(cmd, check=True, shell=True),
• not use commands at all, as it is deprecated since Python2.6 and removed from Python3,

• finally: consider not to check that at all with a shell command and go for pigpio's own features. After importing import pigpio you are required to create at least one instance of the pigpio.pi class - and it will tell you if it fails to connect to the pigpiod daemon:

  pi = pigpio.pi()
  if not pi.connected:
      exit() # or reporting the issue
  

---

There are some other issues with your code. The except clause is catching all exceptions which is something you probably don't want to do without good reason. As currently written it furthermore returns None if the os or commands call itself fails, say if i.e. pidof is not available (I have no idea if that assumption is reasonable); your test would therefore report a false negative with pigpiod actually running.