WCF Service WF Workflow WCF endpoint Operation External

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

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

Host: IIS | App. Fabric Runtime Activities Activity Library Workflow Out of the box Custom Runtime Extensible Execution Environment Extensions Scheduler Persistence Provider Tracking Participant Tooling 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

Variables: Result When to use arguments and variables In. Argument Work. To. Do Do. Work Result Out. Argument Work. To. Do Do. Work 2 Result

• • Manufacturing Service IInventory Contract Reserve. Item IAssembly Contract Schedule. Assembly Manufacturing. Service. xamlx Receive IInventory Reserve. Item Receive IAssembly Schedule. Assembly

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

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

• Other Service Workflow Send Id = 42 Do Work … Do Work Receive Id = 42 Calls Back

Long running adder service

Review of Fourth Coffee Workflow Services

WCF Workflow Services & Going Deeper with Workflow Services