如何跳过子进程超时

Question

I'm reading off a file and looping the websites into a subprocess call which uses a script to connect to it and outputs it to terminal. Some websites do not connect and I need to skip them.

cmd = subprocess.check_output([os.path.dirname(sys.argv[0])+ SCRIPT],  stdin=subprocess.DEVNULL, stderr=subprocess.DEVNULL, timeout=1)

Without the timeout, it just hangs for too long

I tried try and except

try
    cmd = subprocess.check_output([os.path.dirname(sys.argv[0])+ SCRIPT],  stdin=subprocess.DEVNULL, stderr=subprocess.DEVNULL, timeout=1)

except subprocess.CalledProcessError:
    print(e)
    #pass

but it shows an error:

Traceback (most recent call last):
  File "/usr/lib/python3.5/subprocess.py", line 695, in run
    stdout, stderr = process.communicate(input, timeout=timeout)
  File "/usr/lib/python3.5/subprocess.py", line 1072, in communicate
    stdout, stderr = self._communicate(input, endtime, timeout)
  File "/usr/lib/python3.5/subprocess.py", line 1716, in _communicate
    self._check_timeout(endtime, orig_timeout)
  File "/usr/lib/python3.5/subprocess.py", line 1098, in _check_timeout
    raise TimeoutExpired(self.args, orig_timeout)
subprocess.TimeoutExpired: Command '['./SCRIPT timed out after 1 seconds

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./find_prime.py", line 22, in <module>
    stdin=subprocess.DEVNULL, stderr=subprocess.DEVNULL, timeout=1)
  File "/usr/lib/python3.5/subprocess.py", line 626, in check_output
    **kwargs).stdout
  File "/usr/lib/python3.5/subprocess.py", line 700, in run
    stderr=stderr)
subprocess.TimeoutExpired: Command '['./SCRIPT']' timed out after 1 seconds

On some sites it calls the exception and goes to the next site, but on some of them it doesnt even go to the exception and outputs the error shown

Answer 1

You should be able to catch the TimeoutExpired execption and ignore it

try:
    cmd = subprocess.check_output([os.path.dirname(sys.argv[0])+ SCRIPT], stdin=subprocess.DEVNULL, stderr=subprocess.DEVNULL, timeout=1)
except subprocess.CalledProcessError e:
    print(e)
except subprocess.TimeoutExpired:
    pass