473,897 Members | 3,118 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

subprocess returncode always None

Dear All,

I'm currently working on a project that needs to collect the output of
the JHOVE application. More information about the application is
available at this website:

http://hul.harvard.edu/jhove/

The application is written in Java and is executed by a shell script.
There are occasions where this application may get stuck in an
infinite loop. For this reason I've been trying to implement a simple
class that I can use to execute the JHOVE application and if it
doesn't complete in the required period of time to raise an exception
and kill the process.

The class is as follows, apologies for the odd line wrapping.

<snip>
class niceSubprocess( object):
"""
A class that implements a call to the subprocess method with a timeout
- command, the command to execute
- params, the parameters to pass to the application
- timeout, the amount of time in seconds to wait
"""
def executeCommand( self, command, params, timeout):
try:
timeElapsed = 0

process = subprocess.Pope n((command, params), stdin =
subprocess.PIPE , stdout = subprocess.PIPE , stderr = subprocess.PIPE ,
close_fds = True)

while process.poll() == None and timeElapsed < timeout:
print process.poll()
#print process.stdout. read()
timeElapsed = timeElapsed + 1
time.sleep(1)

if process.poll() == None:
# kill off the process, and don't be terribly nice about it
os.kill(process .pid, signal.SIGKILL)
raise timeoutError, timeout
else:
if process.stdout. read() == "":
raise executeError, process.stderr. read()
else:
return process.stdout. read()

except Exception, errorInfo:
# pass the exception to the calling code
raise errorInfo

</snip>

I'm running this on Linux and through the use of top can see the JAVA
process start and complete. The problem I have is that process.poll()
always returns None, even though the application has successfully ran
and returned output.

Can anyone shed some light on why the call to the shell script always
returns None as a return code?

With thanks.

-Corey

--
Corey Wallis
RUBRIC Technical Officer
University of Southern Queensland
http://www.rubric.edu.au
http://techxplorer.wordpress.com
Jul 9 '06 #1
0 2688

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

0
2447
by: Christoph Haas | last post by:
Evening, I'm having trouble with running a process through Python 2.4's subprocess module. Example code: ======================================================== def run(command): run = subprocess.Popen(command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE) # Wait for the process to return
2
3393
by: Jim | last post by:
Hello, I need a program that will traverse a directory tree to ensure that there are unix-style line endings on every file in that tree that is a text file. To tell text files from others I want to use the unix "file" command (Python's "mimetypes" is not so good for me). But I am stuck on something about getting that output, and I'd greatly appreciate any pointers.
4
17565
by: 7stud | last post by:
Hi, What is the difference between: 1) getting the returncode directly from the subprocess object 2) calling poll() on the subprocess object? Here is an example:
12
4549
by: bhunter | last post by:
Hi, I've used subprocess with 2.4 several times to execute a process, wait for it to finish, and then look at its output. Now I want to spawn the process separately, later check to see if it's finished, and if it is look at its output. I may want to send a signal at some point to kill the process. This seems straightforward, but it doesn't seem to be working. Here's my test case:
3
2185
by: jakub.hrozek | last post by:
Hello, My program uses the subprocess module to spawn a child and capture its output. What I'd like to achieve is that stdout is parsed after the subprocess finishes, but anything that goes to stderr is printed immediately. The code currently looks like: try: test = Popen(test_path, stdout=PIPE, stderr=PIPE,
4
5877
by: grayaii | last post by:
There are so many threads on this subject, but I ran across a situation on Windows that I can't figure out. I'm trying to run this little command-line exe and when I launch like this, it hangs: I can run this exe manually via the command prompt and it returns after a few seconds, but more importantly when I run it as follows it works fine:
2
10179
by: rparimi | last post by:
I am trying to redirect stderr of a process to a temporary file and then read back the contents of the file, all in the same python script. As a simple exercise, I launched /bin/ls but this doesn't work: #!/usr/bin/python import subprocess as proc import tempfile name = tempfile.NamedTemporaryFile(mode='w+b') print 'name is '+ name.name
7
6242
by: Samuel A. Falvo II | last post by:
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):
0
1502
by: Albert Hopkins | last post by:
On Mon, 2008-11-17 at 15:27 -0800, rowen wrote: subprocess.call = call(*popenargs, **kwargs) Run command with arguments. Wait for command to complete, then return the returncode attribute. The arguments are the same as for the Popen constructor. Example: retcode = call()
0
9990
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
9837
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
11250
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
10850
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
0
10478
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the choice of these technologies. I'm particularly interested in Zigbee because I've heard it does some...
0
9656
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then launch it, all on its own.... Now, this would greatly impact the work of software developers. The idea...
1
8032
isladogs
by: isladogs | last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM). In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules. He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms. Adolph will...
0
7185
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
3
3300
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.