WCF Service WF Workflow Client Operation WCF endpoint External Service External Service External Service External Service

Execute long running processes Coordinate asynchronous tasks Compose service calls into new services Utilize robust tracking infrastructure Use Workflow Services!

RuntimeRuntime Extensible Execution Environment ActivitiesActivities Activity Library Out of the box Custom RuntimeRuntime WorkflowWorkflow SchedulerSchedulerExtensionsExtensions Persistence Provider Tracking Participant ToolingTooling Out of the Box & Build to Suit VS Designer Rehosted Designer WF Debugger

Sequential Model Use for linear execution patterns where simplicity is key. Requires structured loops that rely on child composite activities (e.g., While activity). Activity layout is rigid.

Flowchart Model Best choice for representing arbitrary cycles. Activity layout is free floating.

State Machine Formal structure for the sequencing of activities Define handlers for entering & exiting a state with activities Define transitions between states using activities as the trigger & expressions as conditions Nest states within one another to share common transitions

DoWorkDoWork WorkToDo Result InArgument OutArgument DoWorkDoWork WorkToDo ResultInArgumentOutArgument DoWork 2 WorkToDo Result DoWorkDoWork WorkToDo Result Result WorkToDo Result When to use arguments and variables

ManufacturingService.xamlxManufacturingService.xamlx Manufacturing Service IInventory Contract ReserveItemReserveItem IAssembly Contract ScheduleAssemblyScheduleAssembly Receive IInventory ReserveItem Receive Receive IAssembly ScheduleAssembly Receive

Define data contract entities (optional) Define Operations with Receive activity Implement Operations with Activities Configure service Host in AppFabric Test with WCF Test Client

WorkflowWorkflow ReceiveReceive SendSend Correlation Query Instance Store Other Service Id = 42 Calls Back Correlation Query Id = 42 Correlation value stored with workflow in instance store, already in message body. Value extracted from message body and used to retrieve workflow from instance store, message delivered Id = 42

WorkflowWorkflow ReceiveReceive SendSend Do Work Other Service Id = 42 Calls Back Id = 42

Long running adder service

Review of Fourth Coffee Workflow Services

WCF Workflow Services & Going Deeper with Workflow Services