Do we need ESB any more? Artur Karaźniewicz
About me •
Artur Karaźniewicz - Chief Integration And Solution Architect, Integration Team Leader - Allianz Poland
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Working with Java since 1999 (JServ anybody?)
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Experience in Financial Services
What’s an ESB? First things first, but not necessarily in that order. -- Doctor Who
What’s an ESB Enterprise Service Bus - term first coined by Gartner around 2002 (although few others claim They coined the term before) (Enterprise Service Bus) Universal integration backbone. An ESB acts as a shared messaging layer for connecting applications and other services throughout an enterprise computing infrastructure. It supplements its core asynchronous messaging backbone with intelligent transformation and routing to ensure messages are passed reliably. Services participate in the ESB using either web services messaging standards or the Java Message System (JMS).
What’s an ESB Sonic Software, one of the first ESB bandwagon members has it's own definition
An ESB is software infrastructure that simplifies the integration and flexible reuse of business components using a service-oriented architecture. An ESB makes it easy to dynamically connect, mediate and control services and their interactions. -- source http://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.html
What’s an ESB IONA has little bit different perception what ESB actually is
In general we agree with Sonic's requirements for an ESB, at a technical level when it comes to how to meet those requirements we think they have got it all wrong. [...] Specifically, he said that Iona believes Sonic's ESB is "overly JMS [Java Message Service] and broker based". -- source http://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.html
What’s an ESB PolarLake, another ESB Vendor adds another view
Great to see Sonic Software's definition converge towards ours. In particular, they are correctly identifying that mediation - a term we have used for quite some time - is the core feature of an ESB. -- source http://www.businessreviewonline.com/blog/archives/2005/12/does_sonics_esb.html
So what’s ESB after all? Odd that we think definitions are definitive. -- Larry Wall, Perl Creator
So What’s an ESB, after all? WS Stack
Adapters/Connectors
Routing and mediation
Messaging Backbone
Legacy Systems
So What’s an ESB, after all? •
A little bit of distribution mechanisms
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Bus Architecture vs. Hub And Spoke
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Strong monitoring and management capabilities
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With little pinch of flexibility...
What ESB is not? •
It’s not an Application Server!
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It’s not centralized nor monolithic
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It’s not BPMS (Business Process Management Suite)
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It’s not MOM
What’s wrong with ESB, then? For every complex problem, there is a solution that is simple, neat, and wrong. -- Henry Louis Mencken
What’s wrong with ESB?
ESB
What’s wrong with ESB? •
It looks Great!..
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...But in practice - most ESBs are typical 80/20 solutions (or simple, neat and wrong)
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80% of (simple) things are very easy to implement using of the shelve ESB
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20% of things are extremely difficult to implement using of the shelve ESB
We have 80% of Perl6 done and we are now working on the next 80%. -- Anonymous Coward, slashdot.org, Perl 6 discussion
Examples? Excerpt from (some) ESB documentation
The Oracle Database adapter does not support the following data types: * PL/SQL TABLE * TABLE * VARRAY * OBJECT etc..
Examples? Excerpt from (some) ESB documentation
The Oracle Database adapter accepts a character data for a NUMBER field without throwing an error. In the database, the character is stored as 0.
What’s wrong with ESB? •
Lack of sound community •
“Community driven” vs. “consultants driven”
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Extremely proprietary solutions
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Proprietary extensions to standards
No standard or clause in a standard has a divine right of existence -- A Microsoft PKI architect explaining Microsoft's position on standards compliance.
What’s wrong with ESB? •
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Focused on Vendor Background •
Application Servers Vendors base their ESB on their Application Servers
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EAI Vendors base ESB on their EAI
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Messaging Vendors base ESB on Message Brokers
Some solutions became ESB for one night...
The trouble is that things never get better, they just stay the same, only more so. -- Terry Pratchett, "Eric"
What’s wrong with ESB? Steve Vinoski, chief engineer of product innovation for IONA Frankly, if I were an enterprise architect today, and I were genuinely concerned about development costs, agility, and extensibility, I’d be looking to solve everything I possibly could with dynamic languages and REST, and specifically the HTTP variety of REST. I’d avoid ESBs and the typical enterprise middleware frameworks unless I had a problem that really required them (see below). I’d also try to totally avoid SOAP and WS-*.
The ESB check list • Contract first development • What does this mean • Why it’s important?
• Agility • Test Driven Development • Contiguous Integration • “Mockability”
The ESB check list •
Standard compliance • WS-* standards compliance (beware of Vendor’s bias!) • Interoperability • WS Stack standard compliance
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Flexibility • REST • SOAP
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Sound Community
CXF the ESB framework My opinions may have changed, but not the fact that I am right. -- Ashleigh Brilliant
What's CXF • IONA Celtix + Codehouse XFire = CXF Celtix is an Open Source, Java Enterprise Service Bus and hosted in the ObjectWeb community. -- http://www.iona.com, in 2006
While Celtix has traditionally called itself an ESB, if you look at the code you'll see that Celtix has primarily focused on providing JAX-WS and WS-* support. The new project will NOT be branded as an ESB. -- http://xfire.codehaus.org/XFire+and+Celtix+Merge
What’s CXF?
• JAX-WS certified stack • Commercially Supported • Embeddable stack
IONA
• J2EE containers (BEA WLS, JBoss, IBM WebSphere, Tomcat, Oracle iAS, Apache Geronimo etc. ) • JBI (Apache Service Mix) • Standalone Spring Container
What’s CXF? WS-* compliant stack
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WS-Addressing,
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WS-Policy,
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WS-ReliableMessaging
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WS-Security
Fully integrated with Spring REST enabled framework through JAX-RS and HTTP binding
CXF architecture Transports JMS
Front-ends
Bindings
JAX-WS
Simple
JAXB
HTTP Local
Bus
Messaging / Interceptors
Aegis
JAX-WS Architecture JAXB 2
SAAJ
JAX-WS
•JAX-WS – Java API for XML WS • JSR 224 (java.xml.soap) • Web Services metadata JSR 170 (java.jws)
••JAXB Java XML Binding API •• JSR 222 (java.xml.bind) ••••Tooling • •WSDL to Java •Java to WSDL •etc... •
Tooling
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•SAAJ •SOAP with Attachments API for Java
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CXF Architecture How does CXF fit into ESB landscape?
WS Stack
CXF Routing and mediation
Messaging Backbone
Adapters/Connectors
Exposing Services Seeing is believing -- American Proverb
Hello World, CXF Way...
Hello World, CXF Way...
Hello World, CXF Way • Look Ma! no XML, no generated artefacts!
• POJO service • Dead simple! Even Your Grandma’ can do it!
• Up and running - in just 19 lines of code!
What’s Wrong with this Example?
• It’s not contract first • It’s just remoting • It runs in built-in HTTP container
Real-world CXF Webservices ShipIt Inc. - Shipping service The contract
Real-world CXF Webservices ShipIt Inc. - Shipping service The contract
Real-world CXF Webservices Generating the service model
Real-world CXF Webservices Generated POJO model
Real-world CXF Webservices Generated POJO model
Real-world CXF Webservices Service Endpoint Interface
Real-world CXF Webservices Implementing the Endpoint
Real-world CXF Webservices Wiring it all together, and deploying
Real-world CXF Webservices •
What's wrong with this service? •
No value constructors
• No toString, hashCode and equals ●
XMLGregorianCalendar?
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No validation
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No Security
Real-world CXF Webservices •
Customizing JAXB binding via xjc plugins • Jakarta Commons Plugin • Value Constructor Plugin ●
Simple Preserve Plugin
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Value Constructor Plugin
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More on: ●
https://jaxb2-commons.dev.java.net/
Real-world CXF Webservices • Getting rid of XMLGregorianCalendar
Real-world CXF Webservices Adding validation and security
Real-world CXF Webservices Putting it all together
Real-world CXF Webservices Putting it all together
Real-world CXF Webservices Monitoring and managing CXF ●
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Built-in JMX monitoring and managing module Exposing custom components
Real-world CXF Webservices ●
Monitoring and managing CXF
Consuming Services There are only two tragedies in life: one is not getting what one wants, and the other is getting it. -- Oscar Wilde
Consuming Services •
Generate Stubs from WSDL, as before
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Use generated Client Stub
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Disadvantages
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No CXF fine-tuning Bloated client No Spring integration
Consuming Webservices Consuming through CXF client API
The same in Spring
Testing Services There are only two tragedies in life: one is not getting what one wants, and the other is getting it. -- Oscar Wilde
Testing services •
Service implementation is just POJO
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Service can be exposed using Endpoint.publish and consumed as a standard endpoint
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Leads to problems with CI servers
Services can be exposed through CXF convenient API, and through local:// (in VM) transport
Real-world CXF Webservices Unit testing CXF services
Do we need ESB? • • • •
In complex scenarios... yes!
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Try to avoid Vendor Lock-in
But maybe You have one already? Check something that works for You Use ESB Check List when selecting concrete solution Community is important!
Questions?
Dziękuję!