After the coordination logic and the activities have been designed, you register these components as workflow and activity types with Amazon SWF. During registration, you specify a name, a version, and default configuration values for each type.
Only registered workflow and activity types can be used with Amazon SWF. In the e-commerce example, you would register the CustomerOrder workflow type and the VerifyOrder, ChargeCreditCard, ShipOrder, and RecordCompletion activity types.
After registering your workflow type, you can run it as often you like. A workflow execution is a running instance of a workflow.
A workflow execution can be started by any process or application, even another workflow execution. In the e-commerce example, a new workflow execution is started with each customer order. The type of application that initiates the workflow depends on how the customer places the order. The workflow could be initiated by a web site or mobile application or by a customer service representative using an internal company application.
With Amazon SWF, you can associate an identifier—called a workflowId—with your workflow
executions, so you can integrate your existing business identifiers into your workflow. In the e-commerce example,
each workflow execution might be identified using the customer invoice number.
In addition to the identifier that you provide, Amazon SWF associates a unique system-generated
identifier—a runId—with each workflow execution. Amazon SWF allows only one workflow execution
with this identifier to run at any given time; although you can have multiple workflows executions of the same
workflow type, each workflow execution has a distinct runId.
