Asynchronous background processes in Python?
- by Geuis
I have been using this as a reference, but not able to accomplish exactly what I need: http://stackoverflow.com/questions/89228/how-to-call-external-command-in-python/92395#92395
I also was reading this: http://www.python.org/dev/peps/pep-3145/
For our project, we have 5 svn checkouts that need to update before we can deploy our application. In my dev environment, where speedy deployments are a bit more important for productivity than a production deployment, I have been working on speeding up the process.
I have a bash script that has been working decently but has some limitations. I fire up multiple 'svn updates' with the following bash command:
(svn update /repo1) & (svn update /repo2) & (svn update /repo3) &
These all run in parallel and it works pretty well. I also use this pattern in the rest of the build script for firing off each ant build, then moving the wars to Tomcat.
However, I have no control over stopping deployment if one of the updates or a build fails.
I'm re-writing my bash script with Python so I have more control over branches and the deployment process.
I am using subprocess.call() to fire off the 'svn update /repo' commands, but each one is acting sequentially. I try '(svn update /repo) &' and those all fire off, but the result code returns immediately. So I have no way to determine if a particular command fails or not in the asynchronous mode.
import subprocess
subprocess.call( 'svn update /repo1', shell=True )
subprocess.call( 'svn update /repo2', shell=True )
subprocess.call( 'svn update /repo3', shell=True )
I'd love to find a way to have Python fire off each Unix command, and if any of the calls fails at any time the entire script stops.
