Pimped Subprocess

This is a library of “pimped up” subprocess modules with monitoring capabilities.

Installation

Simple:

$ pip install pimped_subprocess

Pimped Subprocess

PimpedSubprocess allows you to run subprocesses in a similar manner to Python’s standard subprocesses, except that it allows you to follow the subprocess stdout stream line by line.

import pimped_subprocess
import time

class PrependLineNumber( object ):
    def __init__( self ):
        self._counter = 0

    def __call__( self, line ):
        self._counter += 1
        print( '{:04}:\t{}'.format( self._counter, line ) )

prependLineNumber = PrependLineNumber()
p = pimped_subprocess.PimpedSubprocess( 'ls -l', shell = True )

# must register to get the lines
p.onOutput( prependLineNumber )

# acutally run the subprocess
p.launch()

# wait for it to finish
p.process.wait()
time.sleep( 0.1 ) # wait a little extra to finish reading everything

This code will produce something like this:

0001:   total 44
0002:   drwxrwxr-x 2 yoav yoav 4096 ינו 19 02:40 dist
0003:   drwxrwxr-x 2 yoav yoav 4096 ינו 19 02:52 examples
0004:   -rw-rw-r-- 1 yoav yoav  258 ינו 19 02:35 go.py
0005:   drwxrwxr-x 2 yoav yoav 4096 ינו 19 02:39 pimped_subprocess
0006:   drwxrwxr-x 2 yoav yoav 4096 ינו 18 23:58 pimped_subprocess.egg-info
0007:   drwxrwxr-x 7 yoav yoav 4096 ינו 19 00:38 python2
0008:   -rw-rw-r-- 1 yoav yoav  230 ינו 19 01:28 Rakefile
0009:   -rw-rw-r-- 1 yoav yoav  922 ינו 19 02:54 README.md
0010:   -rw-rw-r-- 1 yoav yoav  700 ינו 19 02:40 setup.py
0011:   drwxrwxr-x 4 yoav yoav 4096 ינו 19 02:34 test
0012:   drwxrwxr-x 2 yoav yoav 4096 ינו 19 01:41 tools

Multiple Output Monitors

You can register multiple output monitors by calling onOutput multiple times:

p.onOutput( callable1 )
p.onOutput( callable2 )
p.onOutput( callable3 )

Process End Event

You can also register to get notified when the process ends:

def myCallback( token, exitCode ):
    print( 'process ended with exit code: {}'.format( exitCode ) )

p.onProcessEnd( myCallback, 'some token here' )

When the process ends, myCallback will be called with the token and the process’s exit code. The token’s job is to help you distinguish between different processes that use the same callback.

Remote Processes

Check out the Closer library for using PimpedSubprocess capabilites on remote (via SSH) processes.

Running the Tests

If you want to run the tests you will need testix and pytest:

$ pip install testix pytest

You’ll also need rake, but at least on recent Ubuntu versions - rake is installed by default.

Once you have all these, from the root of the source tree:

$ rake test

you can see what indivitual test suites exist with

$ rake -T
found 3 test files
rake test                              # run all tests
rake test/test_pimped_subprocess.py    # run tests in test/test_pimped_subprocess.py
rake test/test_real_live_processes.py  # run tests in test/test_real_live_processes.py
rake test/test_remote.py               # run tests in test/test_remote.py

Encodings

The launch() function takes an encoding argument, e.g.

    p.launch( encoding = 'utf-8' )

By default it uses the latin-1 encoding, since this encoding never produces decoding errors, but you can change it if you like.

Windows Support

This library leans on the pty module which seems to be unavailable for Windows. Hence, this is a Unix only library, sorry.