Integrating Microservices with

Apache Camel and JBoss Fuse

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Who?Christian Posta

Principal Middleware Specialist/Architect

Blog: http://christianposta.com/blog

Twitter: @christianposta

Email: christian@redhat.com

• Committer on Apache Camel, ActiveMQ, Fabric8, PMC on ActiveMQ

• Author: Essential Camel Components DZone Refcard

• Frequent blogger and speaker about open-source technology!

Why do we care?

Where are we now?

• Domain modeling

• Object Oriented design

• Functional decomposiiton

• Language specific modularity,

decomposition, fault-tolerance (eg, Erlang)

• Shared libraries?

Decomposition techniques

• Agile methodology

• Doman Driven Design

• REST

• Hexagonal Architectures

• Pipes and Filters

• Actor Model

• SEDA

Microservices emerged as a result…

A new term! Yay!

A concept that helps describe distributed

systems that organically evolve into scalable,

loosely coupled, independently managed sets

of services that work together to deliver

business value with acceptable tradeoffs.

So what are microservices?

Don’t get too caught up in the buzzword bingo;

Microservices is a good concept, but it’s not

itself a panacea.

So what are Microservices?

• Flexible technology choices

• “Smart endpoints” “dumb pipes”

• Independently scalable

• Decentralized, choreographed interactions

• Testable

• Automation, DevOps philosophy

• Design for failure

• Evolving design

Microservice characteristics

• No silver bullet; distributed systems are

*hard*

• Dependency hell, custom shared libraries

• Fragmented and inconsistent management

• Team communication challenges

• Health checking, monitoring, liveness

• Over architecting, performance concerns,

things spiraling out of control fast

Challenges with Microservices!

Why Apache Camel?

Real developers ride Camels!

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Apache CamelApache Camel is an open-source,

light-weight, integration library.

Use Camel to integrate disparate systems

that speak different protocols and data formats

Apache Camel

Enterprise Integration Patterns

http://camel.apache.org/eip

Features

● Enterprise Integration Patterns (EIPs)

● Domain Specific Language to write “flows” or “routes”

● Large collection of adapters/components for legacy

systems, B2B, and SaaS

● Strong Unit test/Integration test framework

● Expression languages

● Data Formats

● Tooling with JBoss Developer Studio

Pipes and Filters

Java DSLpublic class OrderProcessorRouteBuilder extends RouteBuilder {

@Override

public void configure() throws Exception {

from(“activemq:orders”)

.choice()

.when(header(“customer-rating”).isEqualTo(“gold”))

.to(“ibmmq:topic:specialCustomer”)

.otherwise()

.to(“ftp://user@host/orders/regularCustomers”)

.end()

.log(“received new order ${body.orderId}”)

.to(“ibatis:storeOrder?statementType=Insert”);

}

}

Spring XML DSL<route id=“processOrders”>

<from uri=“activemq:orders”/>

<choice>

<when>

<simple>${header.customer-rating} == ‘gold’</simple>

<to uri=“wmq:topic:specialCustomer”>

</when>

<otherwise>

<to uri=“ftp://user@host/orders/regularCustomers” />

</otherwise>

</choice>

<log message=“received new order ${body.orderId}”/>

<to uri=“ibatis:storeOrder?statementType=Insert”/>

</route>

Camel - JBoss Developer Studio

• Dynamic routing options

• REST DSL

• Backpressure mechanisms

• Loadbalancing algorithms / Circuit Breaker

pattern

Heavy Lifting: Camel for Microservices

• “Smart endpoints, dumb pipes”

• Endpoint does one thing well

• Metadata used for further routing

• Really “dynamic” with rules engine (eg,

Drools/BRMS)

Dynamic Routing

• Content Based Router

• Dynamic Router

• Routing Slip

• Recipient List

Dynamic Routing

• Expressive way to define REST endpoints

• POST, REST, PUT

• Auto binding to POJOs

• Plugs into Swagger for interface

definition/documentation

• Uses configurable HTTP engine• camel-netty-http

• camel-jetty

• camel-reslet

• camel-sevlet (deploy into other containers)

• camel-spark-rest

REST DSL (2.14)

REST DSLpublic class OrderProcessorRouteBuilder extends RouteBuilder {

@Override

public void configure() throws Exception {

rest().post(“/order/socks”)

.description(“New Order for pair of socks”)

.consumes(“application/json”)

.route()

.to(“activemq:topic:newOrder”)

.log(“received new order ${body.orderId}”)

.to(“ibatis:storeOrder?statementType=Insert”);

}

}

• Backpressure is a way for a service to flow

control callers

• Detecting when can be difficult

• Need to bound processing queues in a

SEDA

• Take advantage of built in TCP flow control

for socket/http requests

Backpressure with Camel

• Throttle EIP• http://camel.apache.org/throttler.html

• Blocking SEDA Queue

• from(“seda:name?size=100&blockWhenFull=true)

• Configure jetty/netty to use blocking acceptor

queues

• https://wiki.eclipse.org/Jetty/Howto/High_Load

• Using Exception handling/retry and DLQ

logic when getting flow controlled• http://camel.apache.org/error-handling-in-camel.html

Backpressure with Camel

• Useful to keep from overloading a system

(use in conjunction with backpressure if you

can)

• Smart loadbalancing• Sticky

• Random

• Failover

• Circuit breaker

Loadbalance/Circuit breaker

Circuit breaker

Image from http://martinfowler.com/bliki/CircuitBreaker.html

Circuit breakerpublic class OrderProcessorRouteBuilder extends RouteBuilder {

@Override

public void configure() throws Exception {

from(“direct:someinterface”)

.loadbalance()

.circuitBreaker(3, 20000L, MyException.class)

.to(“ibatis:storeOrder?statementType=Insert”);

}

}

Apache Camel

More Information● Camel in Action

● Apache Camel Developer’s Cookbook

● Community website

○ http://camel.apache.org/

Why JBoss Fuse?

RED HAT JBOSS FUSE

Development and tooling

Develop, test, debug, refine,

deploy

JBoss Developer Studio

Web services frameworkWeb services standards, SOAP,

XML/HTTP, RESTful HTTP

Integration frameworkTransformation, mediation, enterprise

integration patterns

Management and

monitoring

System and web services metrics,

automated discovery, container

status, automatic updates

JBoss Operations Network

+

JBoss Fabric Management

Console

(hawtio)

Apache CXF Apache Camel

Reliable MessagingJMS/STOMP/NMS/MQTT, publishing-subscribe/point-2-point, store and forward

Apache ActiveMQ

ContainerLife cycle management, resource management, dynamic deployment,

security and provisioning

Apache Karaf + Fuse Fabric

RED HAT ENTERPRISE LINUXWindows, UNIX, and other Linux

Managing microservice

deployments

• Simplifies deployments

• Provides centralized configuration

• Provides cluster capabilities, coordination

• Service discovery

• Smart load balancing

• Failover

• Versioning

• Visualize your middleware with HawtIO

http://fabric8.io

Demo and Questions