New Update-With-Start API

early-return/starter/main.go

@@ -7,6 +7,7 @@
 
 	"github.com/pborman/uuid"
 	"github.com/temporalio/samples-go/early-return"
+	enumspb "go.temporal.io/api/enums/v1"
 	"go.temporal.io/sdk/client"
 )
 
@@ -20,38 +21,46 @@
 	ctxWithTimeout, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	defer cancel()
 
-	updateOperation := client.NewUpdateWithStartWorkflowOperation(
-		client.UpdateWorkflowOptions{
-			UpdateName:   earlyreturn.UpdateName,
-			WaitForStage: client.WorkflowUpdateStageCompleted,
-		})
-
 	tx := earlyreturn.Transaction{ID: uuid.New(), SourceAccount: "Bob", TargetAccount: "Alice", Amount: 100}
-	workflowOptions := client.StartWorkflowOptions{
-		ID:                 "early-return-workflow-ID-" + tx.ID,
-		TaskQueue:          earlyreturn.TaskQueueName,
-		WithStartOperation: updateOperation,
-	}
-	we, err := c.ExecuteWorkflow(ctxWithTimeout, workflowOptions, earlyreturn.Workflow, tx)
-	if err != nil {
-		log.Fatalln("Error executing workflow:", err)
-	}
 
-	log.Println("Started workflow", "WorkflowID", we.GetID(), "RunID", we.GetRunID())
+	startWorkflowOp := c.NewWithStartWorkflowOperation(client.StartWorkflowOptions{
+		ID: "early-return-workflow-ID-" + tx.ID,
+		// WorkflowIDConflictPolicy is required when using
+		// UpdateWithStartWorkflow. Here we use FAIL, because we do not expect
+		// this workflow ID to exist already, and so we want an error if it
+		// does.
+		WorkflowIDConflictPolicy: enumspb.WORKFLOW_ID_CONFLICT_POLICY_FAIL,
+		TaskQueue:                earlyreturn.TaskQueueName,
+	}, earlyreturn.Workflow, tx)
 
-	updateHandle, err := updateOperation.Get(ctxWithTimeout)
+	updateHandle, err := c.UpdateWithStartWorkflow(ctxWithTimeout, client.UpdateWithStartWorkflowOptions{
+		UpdateOptions: client.UpdateWorkflowOptions{
+			UpdateName:   earlyreturn.UpdateName,
+			WaitForStage: client.WorkflowUpdateStageCompleted,
+		},
+		StartWorkflowOperation: startWorkflowOp,
+	})
 	if err != nil {
-		log.Fatalln("Error obtaining update handle:", err)
+		// For example, a client-side validation error (e.g. missing conflict
+		// policy or invalid workflow argument types in the start operation), or
+		// a server-side failure (e.g. failed to start workflow, or exceeded
+		// limit on concurrent update per workflow execution).
+		log.Fatalln("Error issuing update-with-start:", err)
 	}
-
-	err = updateHandle.Get(ctxWithTimeout, nil)
+	var earlyReturnResult any
+	err = updateHandle.Get(ctxWithTimeout, &earlyReturnResult)
 	if err != nil {
 		// The workflow will continue running, cancelling the transaction.
 
 		// NOTE: If the error is retryable, a retry attempt must use a unique workflow ID.
 		log.Fatalln("Error obtaining update result:", err)
 	}
 
-	log.Println("Transaction initialized successfully")
+	workflowRun, err := startWorkflowOp.Get(ctxWithTimeout)
+	if err != nil {
+		log.Fatalln("Error obtaining workflow run:", err)
+	}
+	log.Println("Transaction initialized successfully, with runID:", workflowRun.GetRunID())
 	// The workflow will continue running, completing the transaction.
+
 }

early-return/workflow.go

@@ -36,6 +36,8 @@ func Workflow(ctx workflow.Context, tx Transaction) error {
 	return run(ctx, tx)
 }
 
+// TODO: workflow should return final Transaction summary, and early return
+// should return some sort of transaction conformation.
 func run(ctx workflow.Context, tx Transaction) error {
 	logger := workflow.GetLogger(ctx)