rewind 0.3.1

Have you ever been nervous of all those DBMSs schema changes when you are deploying your applications? They are gonna take too long, or break backward compatibility? Have you ever thought “Crap, I wish I had stored that information since earlier”? Have you ever felt your writing patterns and your reading patterns differ a lot, making things harder to scale?

CQRS (Command-Query Response Segregation) is an architectural pattern that aims to solve these issues by splitting up your architectural system into two parts:

• A write side that takes care of validating input and optimizes for fast writes. The write side takes commands and outputs corresponding events if the command validates correctly.

• A read side that listens to incoming events from the write side. The read side is optimized for fast reads.

A common concept in CQRS is a event store which sits inbetween the write and the read side. The event store takes care of three things:

• persisting all events to disk.

• being a hub/broker replicating all events from the write to the read side of things.

• allowing fast querying of events so that different parts of the system can be synced back on track and new components can be brought back in play.

rewind is an event store application that talks ZeroMQ. It is written in Python and supports multiple storage backends.