1

Event Driven Architectures with

Camel

Gnanaguru Sattanathan

Twitter:@gnanagurus

Website: bushorn.com

Prajod Vettiyattil

Twitter: @prajods

2

What this session is about

Application Integration

Apache Camel

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 !

7

The Chameleon

It can change color with the container

Camel

JVM

Camel

Tomcat

Camel

JBoss

Camel

Websphere

Camel

Oracle

Fusion

Camel

Jetty

8

Apache Camel

• Integration framework

• Multiple deployment options

• Feature rich

• Simple to program

• Unique scalability features

• Apache License

9

Apache Camel: Components

• More than 100 readymade components

• Covering

– PaaS & Public Clouds

– Social Networks

– Devices

– Almost all standard protocols

10

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

11

Coding with Camel

12

Camel – Code your way

JAVA

SPRING

GROOVY

SCALA

Domain Specific Language

(DSL)

13

A simple file integration

File System

Input

Directory

Output

Directory

File

14

Simple file integration:

Sample Code

<route>

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

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

</route>

15

using Spring XML

Message Broker

( ActiveMQ)

File System – Message Broker

Integration

File System

Input

Directory

Output

Queue

File

16

File System to Message Broker Integration:

Sample Code

<route>

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

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

</route>

17

using Spring XML

Tra

nsfo

rme

r

Message Broker

( ActiveMQ)

Adding a simple transformation

File System

Input

Directory

Output

Queue

File

18

A simple transformation:

Sample Code

<route>

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

<to uri="xslt:file://d:\transform.xsl"/>

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

</route>

19

using Spring XML

A simple Twitter application

Message Broker

( ActiveMQ) Twitter.com

Tweets Tweets

Queue

20

Tweets

A simple Twitter application:

Sample Code

<route>

<from uri="twitter://search

?type=direct

&keywords=JUDCON”/>

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

</route>

21

Event Driven Architectures with

Camel

22

Event Driven Architecture

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

– Event source – Event channel – Event processor

23

EDA

Source

1

Event

Processor 1

Source

2

Event

Processor 2

Source

3

Event

Processor 3

Source

4

Source

5 Source

6 So

urc

es

C

ha

nn

els

P

roc

es

so

rs

24

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

25

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

Sta

ge 1

C

ha

nn

els

us

ing

Qu

eu

es

S

tag

e 2

26

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

27

SEDA with Camel

• SEDA

– Scalability feature in Camel

– Uses thread pools and internal queues

– Enables parallel processing

– Avoids waiting threads

28

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

T

hre

ad 3

SEDA Queue 1

SEDA Queue 2

Split

29

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

30

Camel

Camel as Event Channel

• SEDA queues

• VM queues

• Multi-threaded flow

• Load balanced flow

• Asynchronous API

31

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

32

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

33

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