Merb
then and now
Ezra Zygmuntowicz
http://engineyard.com

Merb
Then
Sept 21st 2006
http://pastie.org/14416
AKA Baby Merb

Merb Now
• merb-core
• merb-action-args • merb-haml
• merb-assets • merb-helpers
• merb-auth • merb-jquery
• merb-builder • merb-mailer
• merb-cache • merb-parts
• merb-gen • merb-slices

Core Tenets of Merb

Merb should be fast
(no code is faster then no code)

Merb should be
memory efficient

Merb code should be
as simple as possible

Merb should be
modular

Merb should be easy to
grok and extend
(by hackers for hackers)

Merb should focus on
the application server
as well as the web
framework

Merb should get out of
your way and be
*flexible*

Most Importantly
Merb should be an
experimentation
ground

Why not just work on
rails?

Monoculture is bad

Everyone wins when
there is competition

Lot’s of merb’s lessons
can be applied back to
rails

Merb-1.0RC drops
tomorrow!
Huge thanks to the
community and all
contributors

merb-stack: training wheels
included

Now with that out of
the way...

Introducing Nanite

Nanite is a new way of
building scalable
backends for web apps

Built around RabbitMQ
• Written in erlang, clusterable, highly
scalable, fast as hell.
• AMQP protocol provides many nice
features
• Transient, Persistent and Transactional
semantics

<3 RabbitMQ

Nanite agents
consist of multiple Actors

Nanite agents advertise
their services and status
Feeds#crawl
advertises:
/feeds/crawl
Load average is advertised
as default status

Nanite Mappers
Track nanites and their advertised services and status
Can do dispatch based on a number of factors
Run inside your Merb or Rails app
State of all nanites is replicated across all mappers

Multiple Dispatch
Styles

Least loaded dispatch
and the fitness function

Agents ping the mapper exchange
every @ping_time seconds.
Mappers track the state of all
nanites and remove them from
mapping if they haven’t reported in
within a timeout

Nanite gives us:
• Presence, we know when nanites are ready
for requests or not.
• Self assembly, nanites can come and go and
can run anywhere with zero configuration
in the mappers.
• Dispatch based on load or any fitness
function that suits your app
• Easily take advantage of cloud

File Streaming

Nanite makes it easy to
scale web app backends
Git it on GitHub:
http://github.com/ezmobius/nanite

Questions?