Just Plain Weird Django: Headless Django

One of the weirder aspects of our system was that even a single installation was not one django. Instead it was one django on the mothership providing the user interface and an agent on each managed server, also built on django.

These agents were headless: they had no human interface. They received XMLRPC calls from the mothership and responded appropriately. I'm not going to go into the design of the XMLRPC calls here, they were simple calls but their application was a bit complicated since real networks can of course lose any call at any time. The XMLRPC stuff started with Graham Binn's work and was then extensively modified for our particular use.

By basing the agents on django any code we used in the mothership could be used in the agents as well. Originally we had the idea that we might put a UI on the agents for debugging, but using the debug page saving and good logging made that pretty much unnecessary. One of the agents XMLRPC calls was to ask it to bundle up its logs and saved debug pages and return them to the mothership, and from there we could download and view the information.

I don't recommend headless django until you have a real logging framework in place and debug page capture, but once you have those you can use django for your machine interface needs as well as your human interface needs.

You might also want a persistent job engine to decouple long processing from the request-response pattern of django, but talking about ours will have to wait for another post.