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I want to run a Python script "test.py" in my usr/local/bin directory, which will create a text file in the same directory and write some brief text to it.

This script is called by a Python subprocess in code that responds to a GET request to my web application, which resides at var/www

subprocess.Popen(["python", "usr/local/bin/test.py"])


The code runs without error, however the text file is not created. The code to to do this is straightforward:

myfile = open('test.txt','w+')
myfile.write("Write some text\n")
myfile.close()


I've tried passing options along with this including shell=True. As well, I've tried to use the interface provided by os.system(), also to no avail.

Just for testing purposes, I've given full permissions to all pertinent directories.

Running the test.py script via CLI works as intended, however not when called by the web application. What could be the issue?

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2 Answers

up vote 1 down vote

There could be several reasons:

  1. The current directory isn't what you expect. When you use subprocess.Popen() without specifying a current directory, the child inherits the current folder from the parent process. So it will run probably in the folder in which the web server was started.

    Try an absolute path.

  2. There is a / missing in your path: /usr/.... Without this, the script will again be search relative to the current directory.

You should really fix your error handling before you try to fix the other issues. You should have gotten a useful error message from the code above. If you didn't, then this is a very bad sign: It means that you won't notice if something breaks later.

At some time in the future, you will make a small change that will break something. Without good error handling, this will go unnoticed.

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up vote 0 down vote

@Aaron, thank you.

Here's the error message that I received:

[1, 'Traceback (most recent call last):\n File "/usr/local/bin/mytest.py", line 2, in \n myfile = open(\'test.txt\',\'w+\')\nIOError: [Errno 13] Permission denied: \'test.txt\'\n', '']


I had understood that I granted full permissions, however maybe I misunderstand user management. How can I ensure that the web server has write privileges? This is Linux Ubuntu (12.04)

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