1

Event Driven Architectures with

Camel

Gnanaguru Sattanathan Twitter:@gnanagurus

Website: bushorn.com

Prajod Vettiyattil Twitter: @prajods

2

What this session is about

v Application Integration

v Apache Camel

v Event Driven Architectures with Camel

3

Application Integration

4

Integration

Middleware

JMS, RMI,

JDBC, FTP,

SNMP, TCP

https, SFTP, SNMP,

TCP, CORBA

1.  Enterprise Service Bus 2.  Integration Framework

1.  Validate, Enrich, Route, Transform

2.  Diverse protocol support

5

The Chameleon

6

Camel is a reptile !

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The Chameleon It can change color with the container J

Camel

JVM

Camel

Tomcat

Camel

JBoss

Camel

Websphere

Camel

Oracle Fusion

Camel

Jetty

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Apache Camel

•  Integration framework •  Multiple deployment options •  Feature rich •  Simple to program •  Unique scalability features •  Apache License

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Apache Camel: Components

•  More than 100 readymade components •  Covering

– PaaS & Public Clouds – Social Networks – Devices – Almost all standard protocols

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Apache Camel: Components AWS HDFS

FILE JDBC

AMQP

JMS

MQTT

MongoDB

NETTY

RMI

WebSockets Zoo Keeper

JGroups

ActiveMQ

NMR Smooks

Esper

XSLT

Velocity

Streams

Twitter

SSH

SQL

TCP

SMTP SMPP SOLR

UDP

XQuery

SIP

SFTP

Cache Hazelcast

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Coding with Camel

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Camel – Code your way

JAVA

SPRING

GROOVY

SCALA

Domain Specific Language (DSL)

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A simple file integration

File System

Input Directory

Output Directory

File

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Simple file integration: Sample Code

<route> <from uri="file://d:\Input"/> <to uri="file://d:\Output"/>

</route>

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using Spring XML

Message Broker ( ActiveMQ)

File System – Message Broker Integration

File System

Input Directory

Output Queue

File

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File System to Message Broker Integration: Sample Code

<route> <from uri="file://d:\Input"/> <to uri="activemq:queue:Output"/>

</route>

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using Spring XML

Tran

sfor

mer

Message Broker ( ActiveMQ)

Adding a simple transformation

File System

Input Directory

Output Queue

File

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A simple transformation: Sample Code

<route> <from uri="file://d:\Input"/> <to uri="xslt:file://d:\transform.xsl"/> <to uri="activemq:queue:Output"/>

</route>

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using Spring XML

A simple Twitter application

Message Broker ( ActiveMQ)

Twitter.com

Tweets Tweets Queue

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Tweets

A simple Twitter application: Sample Code

<route> <from uri="twitter://search

?type=direct &keywords=JUDCON”/>

<to uri="activemq:queue:Output"/> </route>

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Event Driven Architectures with

Camel

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Event Driven Architecture

•  EDA •  A software architecture pattern •  Event: Significant change in state •  Parts of the architecture

–  Event source –  Event channel –  Event processor

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EDA Source

1

Event Processor 1

Source 2

Event Processor 2

Source 3

Event Processor 3

Source 4

Source 5

Source 6 So

urce

s C

hann

els

Proc

esso

rs

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Staged Event Driven Architecture(SEDA)

•  EDA –  Direct and tight coupling of sources and

processors –  Event processor may get swamped with events

•  Reduces performance •  Possible loss of messages

•  SEDA –  EDA decomposed into stages and connected with

queues

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SEDA: one view Source

1

Event Processor 1

Source 2

Event Processor 2

Source 3

Event Processor 3

Source 4

Source 5

Source 6

Channels

Stag

e 1

Cha

nnel

s us

ing

Que

ues

Stag

e 2

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SEDA: another view

Source 1

Source 2

Queue Processor 1

Processor 2

Processor 3 Queue

Queue

Stage 2 Channels using Queues

Stage 1 Channels using Queues

Stage 3

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SEDA with Camel

•  SEDA –  Scalability feature in Camel –  Uses thread pools and internal queues –  Enables parallel processing –  Avoids waiting threads

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Camel with SEDA: comparison

Normalize

Enrich

Split

Route

Waiting thread without SEDA

Thre

ad 1

Receive Receive

Validate

Normalize

Enrich

Route

Parallel processing with SEDA

Thre

ad 1

Thre

ad 2

Th

read

3

SEDA Queue 1

SEDA Queue 2

Split

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Validate

•  Impact –  significant reduction in thread

consumption

•  For 100 concurrent requests –  Without SEDA: 100 threads; With SEDA: 30 threads

Camel as a part of EDA •  Camel as

–  Event channel –  Event processor

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Camel

Camel as Event Channel •  SEDA queues •  VM queues •  Multi-threaded flow •  Load balanced flow •  Asynchronous API

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Camel as Event Processor •  Not ideal as the final Event Processor •  Can be used as an intermediate Event processor •  Routing based on events •  Transformation of events •  Combining simple events •  Event auditing, logging

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Camel and the Actor Model with Akka

•  Actor Model –  Actors

•  Similar to objects, many other features •  Mailbox, behavior/s, internal state

–  No shared state –  Messages between actors –  Locking and Threads are abstracted –  Each actor instance runs in its own thread

•  Akka-Camel –  Integrate Akka to other applications –  Two way: Akka to Camel and Camel to Akka

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Actor

Mailbox State

Behavior

Summary •  Camel

–  Integration Framework –  Simplicity and flexibility –  Components

•  EDA with Camel –  SEDA –  SEDA within Camel –  Camel as part of SEDA

•  Akka and Camel for EDA

34

Questions

35

Gnanaguru Sattanathan Twitter:@gnanagurus

Website: bushorn.com

Prajod Vettiyattil Twitter: @prajods

Our Open Source Middleware Group on LinkedIn http://tinyurl.com/be6e93q