Combing Medusa's Hair... (Design Pattern)
This is an idea I got thinking about COM objects, and getting some support from Mark Hammond, Python's Win32 wizard. The goal is to have a host language (not Python) instantiate an object that runs against the Python interpreter, which lives as its own process. The VMs have various ways of implementing this. Mono isn't that different right? In this design pattern, you have something like a dry cleaner's, where people submit jobs at the counter, and go away right away with a ticket (Python returns -- but keeps running). When they come back is more up to them. Work has been done in the meantime (or not, if the queue is backed up). So Python needs a queue in the front, to accept these job orders, a facility for issuing tickets, and a way to catalog what tasks are completed in some urn or receptacle (given this is Python, we might call it a holy grail). The host process has a method from querying the Python object as to whether such-and-such a job is complete or not. More primitively, it could just check an output bin (folder) for the expected file (perhaps each hair creates a PDF in roughly 1 to 4 seconds). The reason Medusa is useful wordplay is it reminds us of the asynchronous server embedded in early Zope. How Medusa relates to Twisted is lore for others to recount. However, given we're spawning strands, hairs or threads each time a host process calls into our object, we're looking at a multi-snaked environment, so the image could hardly be more apt. The act of combing suggests some synchronization / communication between threads, but that's not a requirement. More on tap here: http://mail.python.org/pipermail/edu-sig/2010-December/010141.html Kirby -- http://mail.python.org/mailman/listinfo/python-list
Re: Combing Medusa's Hair... (Design Pattern)
On Wed, Dec 15, 2010 at 5:04 AM, kirby.ur...@gmail.com kirby.ur...@gmail.com wrote: This is an idea I got thinking about COM objects, and getting some support from Mark Hammond, Python's Win32 wizard. The goal is to have a host language (not Python) instantiate an object that runs against the Python interpreter, which lives as its own process. The VMs have various ways of implementing this. Mono isn't that different right? In this design pattern, you have something like a dry cleaner's, where people submit jobs at the counter, and go away right away with a ticket (Python returns -- but keeps running). When they come back is more up to them. Work has been done in the meantime (or not, if the queue is backed up). Isn't this the way people use queuing systems (ActiveMQ and the like)? Or simply multiprocessing + Queue. -- regards, kushal -- http://mail.python.org/mailman/listinfo/python-list
Re: Combing Medusa's Hair... (Design Pattern)
On Tue, Dec 14, 2010 at 8:10 PM, Kushal Kumaran kushal.kumaran+pyt...@gmail.com wrote: snip In this design pattern, you have something like a dry cleaner's, where people submit jobs at the counter, and go away right away with a ticket (Python returns -- but keeps running). When they come back is more up to them. Work has been done in the meantime (or not, if the queue is backed up). Isn't this the way people use queuing systems (ActiveMQ and the like)? Or simply multiprocessing + Queue. -- regards, kushal Yeah, that's probably right. This is more like a pedagogical metaphor, a mnemonic. As the name for a design pattern, it should probably be confined to Python examples, as that's where the wordplay on Medusa makes some sense, and not just because her hair was all snakes. http://bytes.com/topic/python/answers/26771-twisted-medusa-zope Kirby -- http://mail.python.org/mailman/listinfo/python-list
