Niall's Weblog

MasterSlaveConnection: Works in Pymongo 1.6
In my previous article Python, MongoDB and Pylons – Connection handles and all that lark I described the code and configuration we use at Snaptic for working with Pylons and MongoDB. We use the MasterSlaveConnection class to automatically handle read/write splitting, because we expect to be running a single master/multiple slaves configuration in production.

Broken in Pymongo 1.7
Well, yesterday I upgraded from Pymongo 1.6 to Pymongo 1.7 (just released) and found that unfortunately all the MongoDB stuff breaks, throwing TypeError exceptions when issuing even a simple find_one() query. You will see an error like this one:

TypeError: 'Database' object is not callable. If you meant to call the 'document_class' method on a 'Collection' object it is failing because no such method exists.


But fixed in tip
After talking with Mike Dirolf (Pymongo author) on the MongoDB IRC channel, he came up with a fix within a few minutes. Although I don’t think its in a release yet, if you grab this commit to Pymongo from github, MasterSlaveConnection should work again. He also filed this bug to come up with a more general solution. Cheers to Mike for his super quick turnaround on fixing the bug!