A 64 bit monotonically increasing Id generator for distributed databases.

As soon as you make a departure from an RDBMS for record based storage, you find yourself needing to generate Id's for those records as it's no longer afforded to you in most No-Sql stores.

We wanted to provide a simple solution to this that reused popular infrastructure that companies likely already have running.

• Monotone is a very simple wrapper around popular storage enginges capable of generating monotonically increasing id's that are not vulnerable to the challenges surrounding coorindated system clocks.

• Underyling storage engine maven depdencies are scoped to provided so as to not pollute your depdendency tree for unused storage engine implementations.

• A clean interface with fluent style builders and no checked exceptions is exposed to your codebase.

• Monotone stores local ranges after it reserves them by incrementing a counter in the underlying storage engine implemtnation via atomic supported operations. This permits fast increments via a local AtomicLong in your application and only making a network hop when you have exhausted the local range.

You may want to tune the setMaxIdsToFetch coniguration to your needs as this will dictate how frequent you have to do a write to ZK.

This implementation has an upper bound to its performance, even with a higher limit on setMaxIdsToFetch configured. This is mainly because the implementation does not use sharded counters. This is under consideration for future development.

If setMaxAttempts is reached, a RuntimeException is thrown.

IdGenerator gen = ZKGenerator.newBuilder(zkClient).build();             
long nextId = gen.nextId();

IdGenerator gen = ZKGenerator.newBuilder(zkClient)
                             .setCounterName("orders")
                             .setMaxIdsToFetch(1000)
                             .setRootPath("/id_gen/my_app")
                             .build();
                             
long nextId = gen.nextId();

Free as in beer