En Tue, 07 Oct 2008 21:43:41 -0300, Samuel A. Falvo II
<[EMAIL PROTECTED]> escribió:
I have a shell script script.sh that launches a Java process in the
background using the &-operator, like so:
#!/bin/bash
java ... arguments here ... &
In my Python code, I want to invoke this shell script using the
Subprocess module. Here is my code:
def resultFromRunning_(command):
"""Invokes a shell command, and returns the stdout response.
Args:
command: A string containing the complete shell command to
run.
Results:
A string containing the output of the command executed.
Raises:
ValueError if a non-zero return code is returned from the
shell.
OSError if command isn't found, inappropriate permissions,
etc.
"""
L = log4py.Logger().get_instance()
L.info("Executing: " + command)
p = subprocess.Popen(
command,
shell=True,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.STDOUT,
close_fds=True
)
outputChannel = p.stdout
output = outputChannel.read()
result = p.wait()
if result:
raise(ShellError(command, result, output))
L.info("Result = " + str(output))
return output
When running the aforementioned code, it kicks off the shell script,
and, the shell script kicks off the Java process. However, the Python
code never returns from outputChannel.read() until I explicitly kill
the Java process myself via the kill shell command.
Is your shell script doing something else, apart from invoking the java
process? If not, you could just invoke java directly from Python. Also,
you set stdin=PIPE - is your java process expecting some input? you're not
writing anything to stdin.
Anyway, it's better to use the communicate method instead (it uses select
to read from both stdout and stderr):
p = subprocess.Popen(...)
output = p.communicate()[0]
result = p.returncode
if result: ...
See
http://docs.python.org/library/subprocess.html#subprocess.Popen.communicate
--
Gabriel Genellina
--
http://mail.python.org/mailman/listinfo/python-list
