An overview of using Workflow 4 Services to create long-running stateful services

1. Practical Workflow
Services
Peter Goodman

2. Agenda
 Why Workflow?
 The Workflow Runtime
 Workflow Services
 Windows Server AppFabric
 Demo

3. Why Workflow?
 Visual programming model
 Declarative
 Highly Customizable
 Long running processes
 Human based
 Time based
 Asynchronous

4. The Workflow Runtime
Activity Model
 An Activity is the atomic unit of composition in a workflow
 Pass data into an activity via Arguments
 Store data in Variables
 An activity with no parent is a Workflow

5.  Each activity is scheduled by the runtime
 Each activity execution produces an instance
 Bookmarks pause execution and await some external
influence
 Thread, process, machine agile
The Workflow Runtime
Activity Execution

6.  Persistence stores the state of the workflow
 Tracking raises message events from workflow activities
 Custom extensions
The Workflow Runtime
Extensions

7.  Send and Receive activities
 WCF Infrastructure
 Each workflow definition is hosted as a WCF service
 Correlation is used to find an instance of a workflow definition
and the appropriate bookmark
Workflow Services

8.  IIS administration console UI
 Workflow Management Service
 Wakes up instances
 Handles instance control requests
 Event Collection Service
 Forwards tracking events to Monitoring Store
Windows Server AppFabric

9. Demo
The Approval Workflow

10. Questions?

11.  http://blog.petegoo.com
 pete@petegoo.com
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