pyst2: A Python Interface to Asterisk

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Meta

NOTE: This project is in need of an active maintainer. I’m quite busy with other non-asterisk related projects in my personal time, so if you’re a good Python programmer, and working with this library and Asterisk on a daily basis – please consider maintaining the project! Contact me for more information: r@rdegges.com

In the meantime, I’m happy to accept pull requests and cut releases as needed. If you want to contribute to the project, please do!

Purpose

pyst2 consists of a set of interfaces and libraries to allow programming of Asterisk from python. The library currently supports AGI, AMI, and the parsing of Asterisk configuration files. The library also includes debugging facilities for AGI.

This project has been forked from pyst (http://sf.net/projects/pyst/) because it was impossible for me to contact the project maintainer (after several attempts), and I’d like to bring the project up-to-date, fix bugs, and make it more usable overall.

My immediate plans include adding full documentation, re-writing some of the core routines, adding a test suite, and accepting pull requests.

If you are one of the current maintainers, and would like to take over the fork, please contact me: r@rdegges.com, so we can get that setup!

Installation

To install pyst2, simply run:

$ pip install pyst2

This will install the latest version of the library automatically.

Documentation

Documentation is currently only in python docstrings, you can use pythons built-in help facility:

import asterisk
help (asterisk)
import asterisk.agi
help (asterisk.agi)
import asterisk.manager
help (asterisk.manager)
import asterisk.config
help (asterisk.config)

Some notes on platforms: We now specify “platforms = ‘Any’” in setup.py. This means, the manager part of the package will probably run on any platform. The agi scripts on the other hand are called directly on the host where Asterisk is running. Since Asterisk doesn’t run on windows platforms (and probably never will) the agi part of the package can only be run on Asterisk platforms.

FastAGI

FastAGI support is a python based raw SocketServer, To start the server python fastagi.py should start it listening on localhost and the default asterisk FastAGI port. This does require the newest version of pyst2. The FastAGI server runs in as a Forked operation for each request, in an attempt to prevent blocking by a single bad service. As a result the FastAGI server may consume more memory then a single process. If you need to use a single process simply uncomment the appropriate line. Future versions of this will use a config file to set options.

Credits

Thanks to Karl Putland for writing the original package.

Thanks to Matthew Nicholson for maintaining the package for some years and for handing over maintenance when he was no longer interested.

Thanks to Randall Degges for maintaining this for and accepting pull requests.

Things to do for pyst

This is the original changelog merged into the readme file. I’m not so sure I really want to change all these things (in particular the threaded implementation looks good to me). I will maintain a section summarizing the changes in this README. Detailed changes will be available in the version control tool (currently git).

  • ChangeLog: The ChangeLog needs to be updated from the monotone logs.

  • Documentation: All of pyst’s inline documentation needs to be updated.

  • manager.py: This should be converted to be single threaded. Also there is a race condition when a user calls manager.logoff() followed by manager.close(). The close() function may still call logoff again if the socket thread has not yet cleared the _connected flag.

    A class should be made for each manager action rather than having a function in a manager class. The manager class should be adapted to have a send method that know the general format of the classes.

Matthew Nicholson writes on the mailinglist (note that I’m not sure I’ll do this, I’m currently satisfied with the threaded implementation):

For pyst 0.3 I am planning to clean up the manager.py. There are several know issues with the code. No one has actually reported these as problems, but I have personally had trouble with these. Currently manager.py runs in several threads, the main program thread, a thread to read from the network, and an event distribution thread. This causes problems with non thread safe code such as the MySQLdb libraries. This design also causes problems when an event handler throws an exception that causes the event processing thread to terminate.

The second problem is with the way actions are sent. Each action has a specific function associated with it in the manager object that takes all possible arguments that may ever be passed to that action. This makes the api somewhat rigid and the Manager object cluttered.

To solve these problems I am basically going to copy the design of my Astxx manager library (written in c++) and make it more python like. Each action will be a different object with certain methods to handle various tasks, with one function in the actual Manager class to send the action. This will make the Manager class much smaller and much more flexible. The current code will be consolidated into a single threaded design with hooks to have the library process events and such. These hooks will be called from the host application’s main loop.