Modern Service Oriented Architecture
What does Service Oriented Architecture really mean? When is it relevant? Why might it be interesting? What are the risks? How does it relate to technologies such as web services, message queues and service busses? How does it fit in with business processes, modeling and agility? And - most critically - how can it be put to use in order to build solutions that deliver value, enable the business to evolve, and are reliable, scalable and secure?
This course tackles all of these questions head on. Using an example business throughout the course, issues relating to the design, modeling, publication and ongoing governance of services are examined. And - while this is not a course requiring programming knowledge from attendees - multiple sample implementations of the system will be used to illustrate and explore the impact of various design and technology choices.
Drawing on pertinent underlying theory, while remaining relentlessly practical, this course examines the choices and challenges facing those who approach SOA today.
Audience:
Project leaders, architects and system developers who want to gain an understanding - or improve their basic understanding - of SOA.
Prerequisites:
The course assumes a general awareness of software development, but does not require recent programming experience nor experience as an architect. However, having played either of these roles will help you to get more out of the course. Taking our Software Architecture course first is not required, but will leave you better prepared for this one.
Andy Olsen - author of the course
Andy is a freelance consultant and instructor based in the UK, working mostly in the City of London and Oxford. Andy has been working with .NET since the Beta 1 days and has extensive experience in many facets of .NET development including WCF, WPF, WF, ASP.NET MVC Web development, and mobile applications. Andy has designed and written many Microsoft Official Curriculum courses in the last decade, and has been engaged as author and technical reviewer with Apress on some of their biggest selling books.
Course outline:
Key Architectural Principles
- What is an architecture, anyway?
- Business Processes
- Domain Models and Bounded Contexts
- The need for agility and deferred decision making
- Service Level Agreement
Key Technological Principles
- Distributed systems: a short history
- Consequences of distribution
- Synchronous vs. asynchornous
- Cohesion, coupling and autonomy
- Endpoints
Key Information Principles
- The Information Silo problem
- Information ownership and authority
- The command/event distinction
- Transactions
- The CAP theorem and eventual consistency
- The operational approach
- The messaging approach
- The RESTful approach
- Introduction to the sample business used in the course
Designing Services around Operations
- Modeling processes into services
- ervice classification
- Designing contracts
Operational Implementation: Web Services
- No, Web Services != SOA
- Why deliver services over the web?
- XML
- SOAP
- WSDL
- Exploring a sample implementation
- Considering asynchrony and polling
Evaluation of the Operational Approach
- Consequences for modeling
- Latency
- Reliability
- When things get loopy
- Commands and events revisited
- Publish subscribe
- Message queues, store and forward
- Messages busses
- Brokers vs. busses
Designing with Commands and Events
- Identifying commands and events from the process
- Workflows and sagas
- What is the contract here? What is the service here?
Messaging Implementation Example
- Exploring the implementation
- Examining the event flows
- How reliability is improved
- Sagas
Evaluation of the messaging approach
- Consequences for modeling
- Latency and consistency
- Reliability
- HTTP revisited
- Resources
- How resources relate to the domain
- Hypermedia As The Engine Of Application State
- Processes, behaviors and hypermedia
- Resources
- What is the contract with a RESTful system?
- Exploring the sample implementation
- Correct usage of HTTP status codes
- Approaches to hypermedia
- Media types and content negotiation
- Events and feeds
- Atom, or something else?
- Polling: not so stupid after all
- To bus or not to bus?
Evaluating the RESTful approach
- Consequences for modeling
- Latency and consistency
- Reliability
- What is governance?
- The service portfolio
- Publishing services and contracts
- Evolving services and contracts
- Contract versioning considerations
- Monitoring and quality of service
- Why test?
- Testing at the service level
- Testing service integration
- Chaos monkey
- Cofidentiality and encryption
- Integrity and digital signatures
- Authentication and authorization
- Contrasting approaches with regard to modeling
- Contrasting approaches with regard to coupling and autonomy
- Contrasting approaches with regard to reliability
- SOA opportunities
- SOA risks
- Key things to remember
