Play concurrency

CONCURRENCY IN

PLAY 2.0Ola Wiberg

Wednesday, 11 July, 12

OVERVIEW

• Background

• Play architecture

• Integrated Akka

• API

• Asynchronous IO


A PLATFORM FOR THE FUTURE

"The web has evolved from static to dynamic to real-time."

"Play is a framework for highly-scalable real-time applications!"


DESIGN DECISIONS

• Designed for asynchronous HTTP

• Assumes that any request is long-lived (streams/sockets)

• Concurrency using Actors (Akka) instead of Threads

• Reactive (event based) model for IO

• Keep things simple!


• One process/thread per request

• Resource intense / upper bound limit

• State is handled by the stack

• Requests handled in "isolation"

• Easy to track control flow

• Apache, Tomcat

• Single process for all requests

• Less resource intense

• State maintained in program

• Single event-loop, with event call-backs

• Difficult to track control flow

• Lighttp, Nodejs

BACKGROUNDThreads or Events


A BETTER SOLUTION

• Threads are good

• Events are good

• Why not make use of them both?

• To do it well the complete framework stackneeds to support it!


Java EE compared to Play


Play framework stack


PLAY CONCURRENCY

• Integrated support for Akka

• For concurrent, distributed, event-driven solutions

• Asynchronous IO (play specific)

• Reactive model using Iteratee IO

• Event driven, non-blocking IO (streams/sockets)

• Netty for HTTP

• Asynchronous event-driven framework (NIO)

• Stateless architecture


AKKA

• Akka is used internally for concurrency features in Play

• Built in ActorSystem to be used by the application

• play.api.libs.concurrent.Akka helper object

• Startup new ActorSystems

• Access remote ActorSystems


WHEN TO USE AKKA

• When executing long running tasks.

• Calculations, data crunching, long running queries.

• When accessing web services.

• When accessing remote ActorSystems.

• When scheduling tasks.


CREATE AN ACTORBuilt in ActorSystem


USING AN ACTOR


CREATE AN ACTOR SYSTEM


EXECUTE A TASKWithout creating an Actor


HELPER METHOD


CALLING A WEB SERVICE


REQUEST => RESPONSE


What type of request, stream or regular request?


In-memory request


Stream/socket based request


REACTIVE MODEL

• Handling data streams reactively

• Remove IO stream limitation (Blocking, memory, threads)

• “React” to input only at a rate it is needed (no buffering)

• Implemented using Iteratees, Enumerators, Enumeratees (Consumer/Producer Pattern)

• Topic for another presentation!

Async IO


Example System Overview


SUMMARY

• Play 2.0 is implemented for high concurrency applications

• Play 2.0 has a simple API for concurrency features

• Play 2.0 is great for :

• high throughput, low memory usage

• many concurrent requests / socket connection


THANK YOU!

@OlaWiberg

[email protected]


mailto:[email protected]

mailto:[email protected]

Play concurrency

Technology

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