Broken Pipe from subprocess.Popen.communciate() with stdin
<p>I'm having a strange issue when using subprocess.Popen.communicate().  For background, I want to execute an application from my python script.  When I run the program from the command line, I do it like this (UNIX):</p>

<pre>
$ echo "input text" | /path/to/myapp
</pre>

<p>From my script, I also want to pipe the input into the application.  So, I tried the following.  But I get a "broken pipe" error when I try to send the input with communicate():</p>

<pre>
>>> cmd = ['/path/to/myapp']
>>> p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, stdin=subprocess.PIPE)
>>> out,err = p.communicate('input text')
Traceback (most recent call last):
  File "", line 1, in 
  File "/usr/lib/python2.5/subprocess.py", line 670, in communicate
    return self._communicate(input)
  File "/usr/lib/python2.5/subprocess.py", line 1223, in _communicate
    bytes_written = self._write_no_intr(self.stdin.fileno(), buffer(input, input_offset, 512))
  File "/usr/lib/python2.5/subprocess.py", line 1003, in _write_no_intr
    return os.write(fd, s)
OSError: [Errno 32] Broken pipe
</pre>

<p>To make matters stranger, if I leave out the input data, I don't get any errors.  However, this isn't really a good workaround because the application needs input to work.</p>

<pre>
>>> p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.STDOUT, stdin=subprocess.PIPE)
>>> out,err = p.communicate()
>>> print out
[error from myapp regarding lack of input]
</pre>

<p>Any idea what I'm missing?</p>
