* About
I recently stumbled upon [[https://github.com/soundcloud/roshi][Roshi]], a CRDT set server written on to of Redis.  Roshi
looked like an obvious good usecase for Riak.  Roshiak is a simple demonstration
of how this could be implemented on top of Riak.

Because Roshiak is written on top of Riak it offers some functionality that
Roshi lacks including:

- Elasticity - nodes can be added and removed and Riak will rebalance the data
  automatically.
- Read repair - Riak handles ensuring that all nodes contain the same values for
  a key on read.
- Active Anti-Entropy - Riak will occasionally make sure that the keys on
  various nodes match even without being read.  Roshi-walker implements a
  similar mechanism.  AAE in Riak is implemented using merkle trees, minimizing
  the amount of data moved around.
- Multi datacenter - If you don't mind paying, Riak gives multi datacenter
  support.
- Hinted handoff - If a node goes down, the lost data is shuffled to other
  nodes, ensuring the replication factor is maintained.

Roshiak is implemented in ~140 lines of code, about 1/10th of that of Roshi as
of this writing and supports more operational features.

* How is Roshi better?
Roshi is actually used in production.  Roshiak has not even been tested in
production.  Currently Roshiak is probably slower than Roshi.  Roshiak only
supports getting the entire dataset on read, Roshi supports more sophisticated
'select' calls.  There are a few possible solutions for this in the Roshiak
model depending on requirements.

The Roshi set implementation is also incomplete in that it does not garbage
collect aggressively.

* How do I use it?
Part of doing this project was realizing how behind my help libraries were
relative to their dependencies.  Right now I am working on bringing them up to
date then publishing them through OPAM.  You will also need a local Riak
running. Setting up a devrel is straight forward and documented at the Basho
website.

This won't work yet, but soon!

#+BEGIN_EXAMPLE
opam install riakc
cd roshiak
make examples
#+END_EXAMPLE

You will now have ~examples/roshiak_cli.native~.

#+BEGIN_EXAMPLE
roshiak_cli.native add localhost 8081 snoopdogg foobar
roshiak_cli.native sel localhost 8081 snoopdogg
roshiak_cli.native del localhost 8081 snoopdogg foobar
roshiak_cli.native sel localhost 8081 snoopdogg
#+END_EXAMPLE