rabbit-culler

This is a prototyping project to determine the feasability of emitting events from a PostgreSQL database, and having a daemon watch for these events to do cache invalidation.

There are 2 parts to the project:

• publisher.sql - this SQL script connects to a RabbitMQ exchange and publishes event information. This informations consists of the table name, and the old and new row (or null where appropriate). This is all serialized to JSON.

• uncache.hs - the prototype consumer. This project would be part of the language specific data bindings to the database, and is a daemon that recieves events from RabbitMQ and invalidates the cache appropriately.

  For now, this is written to do uncaching from the MusicBrainz database.

Dependencies

If you want to play with this, you'll need:

• RabbitMQ, running on the default port with default authentication
• PostgreSQL with PL/Python support
• The Python Pika library (http://github.com/pika/pika), version 0.95 (0.96 is not supported)

If you want the caching daemon you'll need:

• GHC
• Haskell libraries:
  • aeson
  • containers
  • amqp
  • memcached