codigo fuente (no es malo leerlo de vez en cuando
)
basicamente es popen, pero espera que que finalice... así que esto frenará tu codigo (se le llama "funciones bloqueantes o "blocking functions", popen no es bloqueante)
este es subprocess.call
def call(*popenargs, timeout=None, **kwargs):
"""Run command with arguments. Wait for command to complete or
timeout, then return the returncode attribute.
The arguments are the same as for the Popen constructor. Example:
retcode = call(["ls", "-l"])
"""
with Popen(*popenargs, **kwargs) as p:
try:
return p.wait(timeout=timeout)
except:
p.kill()
p.wait()
raise
def check_output(*popenargs, timeout=None, **kwargs):
r"""Run command with arguments and return its output as a byte string.
+
− If the exit code was non-zero it raises a CalledProcessError. The
CalledProcessError object will have the return code in the returncode
attribute and output in the output attribute.
The arguments are the same as for the Popen constructor. Example:
>>> check_output(["ls", "-l", "/dev/null"])
b'crw-rw-rw- 1 root root 1, 3 Oct 18 2007 /dev/null\n'
The stdout argument is not allowed as it is used internally.
To capture standard error in the result, use stderr=STDOUT.
>>> check_output(["/bin/sh", "-c",
... "ls -l non_existent_file ; exit 0"],
... stderr=STDOUT)
b'ls: non_existent_file: No such file or directory\n'
"""
if 'stdout' in kwargs:
raise ValueError('stdout argument not allowed, it will be overridden.')
with Popen(*popenargs, stdout=PIPE, **kwargs) as process:
try:
output, unused_err = process.communicate(timeout=timeout)
except TimeoutExpired:
process.kill()
output, unused_err = process.communicate()
raise TimeoutExpired(process.args, timeout, output=output)
except:
process.kill()
process.wait()
raise
retcode = process.poll()
if retcode:
raise CalledProcessError(retcode, process.args, output=output)
return output
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