TechDays 2010 Portugal - Event Driven Architectures - 16x9

Event-Driven Architecture Como, Quando e Porquê?
ARC316
NunoGodinho
Partner & CTO @ ITech4All
nuno.godinho@itech4all.com
@NunoGodinho

Session abstract
Session title

Speaker Bio and Photo
Speaker Name

Nuno Filipe Godinho
Partner & CTO @ ITech4all
Mail: Nuno.Godinho@itech4all.com
Nuno.Godinho@sapo.pt
Blogs: http://pontonetpt.com/blogs/nunogodinho
http://xamlpt.com/blogs/nunogodinho
http://weblogs.asp.net/nunogodinho
http://msmvps.org/blogs/nunogodinho
Twitter: @NunoGodinho
About Me

Introduction
Event Driven Architecture
SOA vs EDA
How to Implement
Resources
Q&A
Agenda

Introduction

SOA is a synchronous RPC (mostly over Web services)
EDA is SOA
The best of EDA and SOA is combined in SOA 2.0
Introduction
Common Thoughts about SOA and EDA

Moving towards on-Demand Business. Why?
Organizations tend to change their structure frequently
Parts of the business process are outsourced to External Partners
Departments and business units are seen now as service providers
Focus not only internally on the organization, but they are seeking for external markets to offer their services
Introduction
Trend Change

Moving towards on-Demand Business. Why?
Everything is moving toward on-demand business where service providers react to impulses from the environment.
Loose coupling between application components
Introduction
Trend Change

Linking application to simplify and automate a process, while avoiding changes to existing applications
Introduction
Sample Painpoint : EAI – Enterprise Application Integration

File Tranfer
Import and Export Files
Common Issues:
Various Formats
Needs Translation
Manually Loaded
Introduction
How to Solve this painpoint?

Shared Databases
Making integration on the Database Level
Several Applications share the same Database
Common Issues:
Data is tightly coupled to multiple applications
Incremental or partial updates are impossible
Introduction

Web Services
Providing Services to automate the integration
Common Issues:
Requires services to be available at invocation
Results in multiple call stacks
Resource consuming
Yet another Remote Procedure Call (RPC, COM, Corba, DCOM, ...)
Introduction

Messaging
Using Messaging mechanisms
Basics:
Defined data format
Asynchronous Operations
Minimized Coupling
Fault Tolerance
Data Freshness
Introduction

Messaging
Defined data format
Contract between Producer and Consumer
Internal formats remain private
Integration is maintained at the edge of the application, to prevent internal changes to impact the interface
Introduction

Messaging
Asynchronous Operations
Processes run on their own context
Source process continues
No need for the service to be always available
Introduction

Messaging
Minimized Coupling
Additive Model reducing the changes needed to existing systems
Reduces dependencies
Increases service reuse
Enable Isolated Service Testing
Introduction

Messaging
Fault Tolerance
Durable Messaging
Improved recoverability
Compensating Actions to handle partial failures
Introduction

Messaging
Data Freshness
Favors small data transfer
Minimized data exchange latency
Introduction

Events
Represent a change in state
Self-Contained
Pure and complete representation of an Event
No references to other data sources
Reduces dependencies, Loosens coupling
Uniquely indentified
Enabled idempotent handling events
Improves tracebility of related processing
Allows correlation with related events
Introduction

Events
Time relevant, not time sensitive
Sourced using messaging
Observable
Published events can be observed by multiple subscribers
Event stream Processing
Introduction

Event Types
Execution
Lifecycle
Management
Business
Introduction

Architecture pattern that orchestrates behavior around:
Production
Detection
Consumption of events as well as the responses they invoke.
A method for building enterprise systems in which events flow between decoupled components and services
A maintainable, sustainable and extensible model for building complex, distributed applications
What is EDA?

Suited for Asynchronous, unpredictable environments
Extremely Loosely Coupled
Inversion of communication
What is EDA?

Companies must manage and react to a large number events every day in real time
Real time trade settlement systems
Flight reservation system
Streaming stock data
Real time vehicle location for transportation companies
Stock Exchange Market systems
System designers normally must support both events and Services
Systems must be “Business Oriented”
Why do we need EDA?

Concerns events that are directly related to specific, measurable changes of condition
Simple Event Processing

Both ordinary and notable events happen
Stream Event Processing

Allows patterns of simple and ordinary events to be considered to infer that a complex event has occurred
Complex Event Processing

SOA-2: Event-Driven Service Oriented Architecture
What is Complex Event Processing?
Event Stream Processing
Complex Event Processing
time
1
2
3
4
5
6
7
8
9
Event pattern of significance where prompt detection and action can have materially impact

What is Complex Event Processing?
WHEN
MSFT price moves outside 2% of MSFT-15-minute-VWAP
FOLLOWED-BY(
S&P moving by 0.5%
AND(
HPQ’s price moves up by 5%
OR
MSFT’s price moves down by 2%
)
)
!
ALL WITHIN
any 2 minute time period
S&P500
!
!
MSFT 15-MIN-VWAP
!
NYSE
NASDAQ
THEN
BUY MSFT
SELL HPQ
time
Multiple data streams
Temporal sequencing
Complex event sequences
Real-time Data Streams
Real-time constraints
Automated actions

Implementation Components

Event Processing Engine

Event Generator
Event Channel
Event Processing Engine
Downstream Activity
Event Flow Layers

Event-driven Process
Automating the basic process
OTHER SERVICES
OTHER SERVICES
OTHER SERVICES
Investment manager wants order management system integrated with trading desk
ECN
ORDER MANAGEMENT SYSTEM
BROKER
TRADINGDESK
EXCHANGE
TRADER

Event-driven Processes
Operational improvement
OTHER SERVICES
OTHER SERVICES
COMPLIANCEENGINE
OTHER SERVICES
TRADINGDESK
President wants compliance engine to monitor trading activities to eliminate cash liability during market swings
INBOUNDTRANSFORMATION
OUTBOUNDTRANSFORMATION
?
ECN
BROKER
EXCHANGE
TRADER
FUND MANAGER

Event-driven Processes
Keeping up with regulations
OTHER SERVICES
COMPLIANCE ENGINE
LOGGING SERVICE
OTHER SERVICES
OTHER SERVICES
TRADINGDESK
DB
Board wants trades logged for Sarbanes-Oxley and integrated with company-wide risk management
INBOUNDTRANSFORMATION
OUTBOUNDTRANSFORMATION
TOCORPORATERISK MGT
?
ECN
BROKER
EXCHANGE
TRADER
FUND MANAGER

SOA vs EDA

SOA vs EDA
SOA Core Services

SOA provides an organizing and delivery paradigm that derives greater value by reusing existing software solutions rather than duplicating capabilities
SOA establishes services as the mechanism by which needs and capabilities are brought together
SOA standardizes the necessary interfaces and behavior to support interaction
SOA vs EDA
What is SOA?
Service
S
Capabilities performed by one for another to achieve a desired outcome
Oriented
O
When capabilities are self-contained and independent to enable a collection of services to be linked together to solve a business problem
Architecture
A
The fundamental organization of a system embodied in its capabilities, their interactions, and the environment

SOA vs EDA
Service Oriented Architecture
Applications are composed in design-time
Linear flow between services
Predictable behavior
Request/Response is common, and often overused
Applications are composed at run-time
Asynchronous components
Reactive behavior

Support strong cohesion in the business processes, situations where all process steps are under one control
Commonly applied to:
Verticalinteraction between the hierarchical layers of functional decomposition
Functional request-and-reply processes such as man-machine dialogues; the user waits for an answer
Processes with a transactional nature which require commit and rollback facilities
Data enrichment in a message to be published to bring the message to its full content in a formal format
SOA vs EDA
When to use SOA?

Support independency between business process steps
Commonly applied to:
Horizontal communication between tiers in a process chain
Workflow type of processes
Processes that cross recognizable functional organization borders, external (B2B) as well as internal
SOA vs EDA
When to use EDA?

SOA vs EDA
Visualization

How to Implement

Using Web service technologies today, and additional SOAP-aware message queuing infrastructure.
Current ESB infrastructures provide a way of message queuing combined with Web service technologies.
SOA and EDA implementations must be regarded in the context of Business Process Management (BPM)
How to Implement

Modern BPM-tools are based on BPEL (Business Process Execution Language)
Current BPEL implementation focuses strongly on the command-and-control model, the orchestration of services, and so on SOA
Beside orchestration BPEL - to a certain extend - also supports workflow, a kind of choreography, which goes in the direction of EDA
BPEL has a procedural nature
EDA would rather be a declarative model.
How to Implement

Preparatory steps:
Model business requirements into functions at the granularity level of the desired autonomy.
Outline the application landscape to identify all affected systems.
Map the application landscape to the business function model.
Identify applications that cross functional borders as potential "agility bottlenecks" (assign a special high priority to those applications that are required to cross external organization borders).
Basis for the decoupled service boundaries
How to Implement
Scenarios where SOA and EDA can easily co-exist

Resources

Enterprise Integration Patterns (GregorHohpe and Bobby Woolf )
Patterns for Enterprise Architecture (Martin Fowler)
SOA Patterns (ArnonRotem-Gal-Oz, Eric Bruno, UdiDahan)
Resources
Books

Event Processing: Designing IT Systems for Agile Companies (K. Chandy, W. Schulte)
Event-Driven Architecture: How SOA Enables the Real-Time Enterprise (Hugh Taylor, Angela Yochem, Les Phillips, Frank Martinez)
SOA Design Patterns (The Prentice Hall Service-Oriented Computing Series from Thomas Erl)
Resources
Books

http://soapatterns.net/
http://www.enterpriseintegrationpatterns.com/
Resources
Sites

TechDays 2010 Portugal - Event Driven Architectures - 16x9

by Nuno Godinho on Apr 29, 2010

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