Develop Reference

using popen shows WindowsError: [Error 2] The system cannot find the file specified

windows 7 python 2.7
when I use popen to open a process：
from ctypes import *
dldtool = cdll.LoadLibrary(r'main.dll')
cmd = "dld_tool -c {} -r programmer.bin -f {}".format(port,file)
print cmd
with LOCK:
process = Popen(cmd, stdout=PIPE)
while process.poll() is None:
out = process.stdout.readline()
if out != '':
print out
error occurs：
process = Popen(cmd, stdout=PIPE)
File "C:\Python27\lib\subprocess.py", line 390, in __init__
errread, errwrite)
File "C:\Python27\lib\subprocess.py", line 640, in _execute_child
startupinfo)
WindowsError: [Error 2] The system cannot find the file specified
The main.dll is in the working directory. should I change the code in python or change the any config?

You should use either the shell=True parameter if you want to pass the entire command with arguments as one string:
process = Popen(cmd, stdout=PIPE, shell=True)
or shlex.split to split your command line into a list (after importing shlex):
process = Popen(shlex.split(cmd), stdout=PIPE)
Otherwise the entire command line with arguments would be treated as one file name, and the system naturally would not be able to find it.

Python : WindowsError: [Error 6] The handle is invalid

I am trying to develop python plugin on QGIS and I am trying to execute binary programs using subprocess :
program = os.path.join(self.tranusConf.tranusBinPath,'pasos' + self.extension)
if not os.path.isfile(program):
logging.error('The <pasos> program was not found in %s'%self.tranusBinPath )
return 0
outpasos = os.path.join(self.resultDirectory, "outpasos.txt")
outpasoserr = os.path.join(self.resultDirectory, "outpasoserr.txt")
args = [program, self.tranusConf.scenarioId, " "]
result = subprocess.Popen(args,stdout=open(outpasos, "w"), stderr = open(outpasoserr, 'w'), close_fds = False, cwd = self.tranusConf.workingDirectory) # Success!
return 1
I get this problem:
An error has occurred while executing Python code:
WindowsError: [Error 6] Descripteur non valide Traceback (most recent call last): File "C:/Users/emna/.qgis2/python/plugins\OptionsTRANUS\launch_tranus_dialog.py", line 109, in run_tranus
interface.runTranus(tab.spin_box.value())
File "C:/Users/emna/.qgis2/python/plugins\OptionsTRANUS\LcalInterface.py", line 426, in runTranus
self.runPasos()
File "C:/Users/emna/.qgis2/python/plugins\OptionsTRANUS\LcalInterface.py", line 311, in runPasos
result = subprocess.Popen(args,stdout=open(outpasos, "w"), stderr = open(outpasoserr, 'w'), close_fds = False, cwd = self.tranusConf.workingDirectory) # Success!
File "C:\OSGEO4~1\apps\Python27\lib\subprocess.py", line 703, in __init__
errread, errwrite) = self._get_handles(stdin, stdout, stderr)
File "C:\OSGEO4~1\apps\Python27\lib\subprocess.py", line 839, in _get_handles
p2cread = self._make_inheritable(p2cread)
File "C:\OSGEO4~1\apps\Python27\lib\subprocess.py", line 878, in _make_inheritable
_subprocess.DUPLICATE_SAME_ACCESS)
WindowsError: [Error 6] Descripteur non valide
I searched for others who have the same error, and they propose to invoke shell = True or use os.popen but it is not working.
For information, I am working on Windows 7 64 bits.

Solved : I added shell = True
proc = subprocess.Popen(args,shell=True,stdout=open(outimploc, 'w'), stderr=open(outimplocerr,'w'),stdin = subprocess.PIPE, cwd=self.tranusConf.workingDirectory).communicate()

I found a partial solution to my problem :
devnull = open(os.devnull, 'wb')
result = subprocess.Popen(args,stdout = open(outtrans, "w"), stderr = open(outtranserr,'w'),stdin=devnull, cwd = self.tranusConf.workingDirectory).communicate()
It works. but I am embarrased in my plugin with the multiple opens of windows cmd of the programs that are executed. This is not esthetically beautiful for my plugin.
Edit : the same with using stdin=subprocess.PIPE

Python script to get execution time using "time"

I need my script to execute a binary file a number of times and get some statistics about its execution time using the the "time" directive. However the following code crashes:
cmd = ["time", "./executable", "<", "input_file"]
result = subprocess.Popen(cmd, stdout = subprocess.PIPE, stderr = subprocess.PIPE)
with the following message:
File "exec_script.py", line 15, in
result = subprocess.Popen("time ./quake < small_input", stdout = subprocess.PIPE, stderr = subprocess.PIPE)
File "/usr/lib/python2.7/subprocess.py", line 710, in init
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
I have been cracking my skull for hours now and can't figure this out, any help? Note that if I just run that command from the same directory, it works. But not through the script.

Collecting stderr in memory with subprocess.call

I'm trying to collect stderr in memory, instead of directly writing it to a file or stdout. I do this so I can generated the error log file in a certain way. I found a library called StringIO that is an in-memory 'file'. I don't think it does the trick. Here's my code:
buffer = StringIO.StringIO()
status = subprocess.call(args, stdout=log_fps["trace"], stderr=buffer)
if status and self.V_LEVEL:
sys.stderr.write(buffer.getvalue())
print "generated error"
if status:
log_fps["fail"].write("==> Error with files %s and %s\n" % (domain_file, problem_file))
log_fps["fail"].write(buffer.getvalue())
I get the following error:
Traceback (most recent call last):
File "./runit.py", line 284, in <module>
launcher.run_all_cff_domain_examples("ring")
File "./runit.py", line 259, in run_all_cff_domain_examples
result = self.run_clg(in_d["domain"], in_d["problem"], in_d["prefix"])
File "./runit.py", line 123, in run_clg
status = subprocess.call(args, stdout=log_fps["trace"], stderr=buffer)
File "/usr/lib/python2.7/subprocess.py", line 493, in call
return Popen(*popenargs, **kwargs).wait()
File "/usr/lib/python2.7/subprocess.py", line 672, in __init__
errread, errwrite) = self._get_handles(stdin, stdout, stderr)
File "/usr/lib/python2.7/subprocess.py", line 1075, in _get_handles
errwrite = stderr.fileno()
AttributeError: StringIO instance has no attribute 'fileno'
I guess this means that I can't use StringIO to collect stderr in memory. What else can I do, short of writing to a file in /tmp?

stdout = subprocess.check_output(args)
See check_output documentation for more options.
If you don't want to capture stdout, use Popen.communicate:
from subprocess import Popen, PIPE
p = Popen(args, stdout=log_fps["trace"], stderr=PIPE)
_, stderr = p.communicate()

import subprocess
p = subprocess.Popen(args, stdout=log_fps["trace"], stderr=subprocess.PIPE)
_, stderr = p.communicate()
print stderr,

pygtk OSError: [Errno 2] No such file or directory. subprocess.Popen PIPE command

I'm new to python and I'm trying to make a search bar that searches only 2 directories using two find commands and output the results into an ordered list [].
def search_entry(self, widget,):
s1 = subprocess.Popen(['find /home/bludiescript/tv-shows', '-type f'], shell=False, stdout=subprocess.PIPE)
s2 = subprocess.Popen(['find /media/FreeAgent\ GoFlex\ Drive/tobins-media', '-type f'], stdin=s1.stdout, shell=False, stdout=subprocess.PIPE)
s1.stdout.close()
self.contents = "\n".join(self.list)
s2.communicate(self.contents)
My search bar:
self.search = gtk.Entry()
self.search.connect("activate", self.search_entry,)
self.box1.pack_start(self.search, True, True, 0)
self.search.show()
errormsg:
File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1228, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory

Separate all the arguments in the args list:
s1 = subprocess.Popen(['find','/home/bludiescript/tv-shows', '-type','f'], shell=False, stdout=subprocess.PIPE)
s2 = subprocess.Popen(['find','/media/FreeAgent\ GoFlex\ Drive/tobins-media', '-type', 'f'], stdin=s1.stdout, shell=False, stdout=subprocess.PIPE)
OUTPUT on MINE
>>> import subprocess
>>> s1 = subprocess.Popen(['find /home/bludiescript/tv-shows', '-type f'], shell=False, stdout=subprocess.PIPE)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python2.7/subprocess.py", line 672, in __init__
errread, errwrite)
File "/usr/lib/python2.7/subprocess.py", line 1201, in _execute_child
raise child_exception
OSError: [Errno 2] No such file or directory
>>> s1 = subprocess.Popen(['find','/home/bludiescript/tv-shows', '-type','f'], shell=False, stdout=subprocess.PIPE)
>>> find: `/home/bludiescript/tv-shows': No such file or directory
The first is your original code and it raises the python exception. The second runs correctly but "find" complains because I do not have a "bludiescript/tv-shows" directory on my system.

Did you mean find on line 2? it looks like it is erroring on finding the file "fine"