aesop

A keen Observer of changes that can also relay change events reliably to interested parties. Provides useful infrastructure for building Eventually Consistent data sources and systems.

Releases

Release	Date	Description
Alpha release	December 2013	Proof of concept code in "sandbox"

Getting Started

aesop aims to leverage capabilities from a at least a couple of good projects that already exist in this space viz.

• LinkedIn Databus
• Netflix Zeno
• NGDATA hbase-sep

The "sandbox" module currently contains proof of concept code to do the following:

• Relay : An implementation of the Databus Relay that uses a Producer to create change events of the sample 'Person' type.
  • Runtime dependencies : None
• Relay Client : An implementation of a Consumer that connects to the sample Relay and consumes change events of the sample 'Person' type.
  • Runtime dependencies : A running 'Relay'
• Bootstrap Producer : A Bootstrap i.e. special Consumer that is used for creating snapshots for change events of the sample 'Person' type. Stores these snapshots in a MySQL DB.
  • Runtime dependencies : A running 'Relay'
• Bootstrap Server : A Bootstrap server that provides a Http interface for slow Consumers to run catch-up queries on. Returns snapshots stored by the 'Bootstrap Producer' for change events of the sample 'Person' type.
  • Runtime dependencies : None
• Bootstrap Client : A sample bootstrap consumer that consumes snapshots in catch-up mode for change events of the sample 'Person' type.
  • Runtime dependencies : A running 'Bootstrap Server'

HBase examples

The "sandbox" module also has some samples for consuming WAL edits from HBase writes and making these available for consumption via a Databus Relay:

• WALEditRelayMain : An implementation of the Databus Relay that uses a WALEditPersonEventProducer that listens to HBase WAL edits and creates change events of the sample 'Person' type.
  • Runtime dependencies : None
• SchemaSetupMain and [PersonDataInjesterMain] (https://github.com/regunathb/aesop/blob/master/sandbox/src/org/aesop/relay/hbase/PersonDataInjesterMain.java) : Classes to create a sample HBase table schema and push data to it. Useful in testing the WAL edits Relay.
  • Runtime dependencies : None