Question

I’m trying to use python subprocess.call with args to call a shell script. The args I have aren’t being passed to the shell script, but the script is being called no problem. Here’s what I’ve got

prepend = str(prepend)
print "prepend = " + str(prepend)
filename = str(request.FILES['mdbfile'])
print "filename = " + str(filename)
PROJECT_ROOT = os.path.abspath(os.path.dirname(__file__))
print "PROJECT_ROOT = " + str(PROJECT_ROOT)
filename = str(PROJECT_ROOT) + '/%s' % filename
print "full_filename = " + str(filename)
cmd = '%s/buildcsvs.sh' % (PROJECT_ROOT)
print "full_cmd = " + str(cmd)
p = subprocess.call([cmd, filename, prepend], shell=True)
output = p.stdout.read()
print output

Here’s what the shell script looks like

#${1} is the file name, ${2} is the prepend code
echo "mdb-export ${1} TEAM > \"${2}team.csv\""
mdb-export ${1} TEAM > "${2}team.csv"

And here’s what the output looks like

prepend = 749176818
filename = 2011ROXBURY.mdb
PROJECT_ROOT = /Planner
full_filename = /Planner/2011ROXBURY.mdb
full_cmd = /Planner/buildcsvs.sh
Exception AttributeError: AttributeError("'_DummyThread' object has no attribute   '_Thread__block'",) in <module 'threading' from '/usr/lib/python2.7/threading.pyc'> ignored
mdb-export  TEAM > "team.csv"
Usage: mdb-export [options] <file> <table>

Does anyone have any idea what I’m doing wrong? Thank you — I appreciate your help

EDIT: Right now, I have this:

print "full_cmd = " + str(cmd)
args = "%s %s" % (filename, prepend)
print "full_args = " + str(args)
(out, err) = Popen(cmd,  stdin=PIPE, stdout=PIPE, stderr=PIPE, close_fds=True).communicate(args)

and it doesn’t look like it’s successfully completing the call to the script.

Do you have any idea why?

Answer 1

If you pass shell=True args must be a string and not a list:

In [4]: from subprocess import check_output

In [5]: check_output(['echo', '123'])
Out[5]: '123\n'

In [6]: check_output(['echo', '123'], shell=True)
Out[6]: '\n'

In [7]: check_output('echo 123', shell=True)
Out[7]: '123\n'

Edit: Instead of using call and p.stdout.read you should use Popen().communicate, that was made for this purpose and it helps to avoid deadlocks.

Edit² (answer to edit above):

cmd = ' '.join([cmd, args])
(out, err) = Popen(cmd,  stdin=PIPE, stdout=PIPE, stderr=PIPE, close_fds=True, shell=True).communicate(None)

You have to pass the full commandline to Popen. The Argument to communicate will be written into the process.stdin (process = what Popen returns).