This is a simple proxy for mongodb.
You can use this to debug queries from your application to mongodb without changing your application code. It parses the mongo/bson protocol on the wire, so you can hack and slow some queries.
Although it uses gevent and can handle a couple of thousand connections with ease, its intended to be used for development purposes.
$ virtualenv env $ ./env/bin/python setup.py develop
$ ./env/bin/mongo-proxy --mongo=localhost:27017 --listen=localhost:29017
then you can connect your application to localhost:29017 and see your queries and responses.