ZeroMQ as scriptable sockets

Bear Metal OÜ| Õismäe tee 78-25, 13513 Tallinn, Harjumaa, Estonia | [email protected]

ZeroMQ as scriptable sockets

Realtimeconf EU 2013Lyon - http://realtimeconf.eu/

Lourens Naudé

Monday, April 22, 13

mailto:[email protected]


http://webtechcon.de/2012/railswaycon/

http://webtechcon.de/2012/railswaycon/


Why this talk ?





Operations / Platform





Credentials

ZeroMQ monitoring supportczmq co-maintainerRuby bindingExperimental TLS support



99% of deployments don’t need enterprise

reliability

Of reliability



Then ...



... now



Zero broker, admin, cost, waste, price tag and (almost) zero latency

What is ZeroMQ ?





What it isn’t





IM for apps

Not a server or message queueA libraryCommunication / concurrencyMessaging semantics for sockets



BSD API

sock.bind(“inproc://workers”)sock.connect (“tcp://0.0.0.0:30”)sock.send (“message”)msg = sock.recv ()sock.close ()



Community

30+ language bindings ...



Super (scriptable) sockets

What is a ZeroMQ socket ?





bind () or connect () to multiple endpoints,

simultaneously

Multiple endpoints





bind () or connect () in any order

Async connect





Socket types

PUB SUB

REQ REP

PUSH PULL





Request / reply

REQ

REP

REQ

REP REP

REP

REQ REQ





Request / Reply usage

Lock stepBi-directionalRoutableFlow control, orchestration etc.



Publish / subscribe

PUB

SUB SUB SUB





Inversion - logging

SUB

PUB PUB PUB





Publish / subscribe usage

Market data, game state etc.PUB socket distributesSUB socket filtersSubscription forwarding (3.x)



Pipeline

PUSH

PULL PULL PULL





Pipeline usage

Extendable - UNIX pipesRound-robin distributionTasks with variable processing



Transport agnostic

inproc:// - threads in a processipc:// - processes on a boxtcp:// - nodes in a networkUniform API



Lightweight switchesDevices





pub/sub persistence

PERSISTENCEDEVICE





Device main loop

loop do m = sub_socket.recv () persist (m) pub_socket.send (m)end





Use cases

ProxyRouting (LRU)Filtering / de-dupTranslation



Work distribution

PUSH

PULL

PUSH

PULL

PULL

PUSH

PULL

PUSH

VENTILATOR

SINK




PUSH

PULL

PUSH

PULL

PULL

PUSH

PULL

PUSH

VENTILATOR

SINK

PUSH

PULLBear Metal OÜ| Õismäe tee 78-25, 13513 Tallinn, Harjumaa, Estonia | [email protected]

Scalable work distribution





Interjection Principle

Scalable topologies



Saving bandwidth

SUBPUB

PUB

SUB SUB

SUB SUB





Asynchronous external dependencies.

Resiliency



Atomicity

Atomic message deliveryUnbound message sizeSend 5GB, recv all or nothing



Availability

Delayed retry on failureMulti bind() and connect()Unordered bind() or connect()



Reliability as patterns

Lazy Pirate (REQ / REP)Majordomo (queue)Titanic (persistence)Binary Star (High Availability)See http://zguide.zeromq.org


http://zguide.zeromq.org

http://zguide.zeromq.org


ZeroMQ concurrency

PUSH

PULL PULL PULL

MAIN THREAD

THREAD 1 THREAD 2 THREAD 3

I/OTHREAD





s = ctx.bind(:PUSH, "inproc://w")3.times{ spawn_worker(ctx) }loop do msg = work.shift break if msg == “exit” s.send(msg)end

Master (work distributor)





Thread.new do s = ctx.connect(:PULL, “inproc://w”) loop do msg = s.recv break if msg == "quit" process(msg) endend

Workers (consumer threads)





Mongrel2Case study





How it works

Multi-protocolZeroMQ for backendsAsync backend requestsLanguage agnostic (bindings)



Mongrel2 topology

PULL

PUB

PULL

PUB

PUSH

SUB

BACKEND A BACKEND B

MONGREL2

CLIENT





Mongrel2 protocol

UUID ID PATH SIZE:HEADERS,SIZE:BODY





Mongrel2 HTTP request

PUSH PULL

AB23 4 /uri SIZE:HEADERS,SIZE:BODY





Mongrel2 HTTP response

SUB PUB

AB23 4 /uri SIZE:HEADERS,SIZE:BODY





Questions ?(... or sync up after)

O fim

fork @methodmissingfollow @methodmissing


ZeroMQ as scriptable sockets

Technology

13 bear metal

info bearmetal

isme tee 78

bind

msg

zeromq

sock

bodymonday