Add dynamic workflow sample

Author: yuandrew

README.md

@@ -149,6 +149,9 @@ Workflow Definition and an Activity Definition using API Key to authenticate wit
 
 These samples demonstrate some common control flow patterns using Temporal's Go SDK API.
 
+- [**Dynamic Workflows**](./dynamic-workflows): Demonstrates how to execute Workflows and Activities dynamically,
+  using a single "Dynamic Workflow"
+
 - [**Dynamic Execution**](./dynamic): Demonstrates how to execute
   Workflows and Activities using a name rather than a strongly typed function.
 

dynamic-workflows/README.md

@@ -0,0 +1,15 @@
+# Dynamic Workflows and Activities
+
+The purpose of this sample is to demonstrate registering and using dynamic workflows and activities to
+handle various workflow types at runtime.
+
+### Steps to run this sample:
+1) Run a [Temporal service](https://github.com/temporalio/samples-go/tree/main/#how-to-use).
+2) Run the following command to start the worker
+```
+go run dynamic-workflows/worker/main.go
+```
+3) Run the following command to start the example
+```
+go run dynamic-workflows/starter/main.go
+```

dynamic-workflows/activities.go

@@ -0,0 +1,20 @@
+package dynamic_workflows
+
+import (
+	"context"
+	"fmt"
+	"go.temporal.io/sdk/activity"
+	"go.temporal.io/sdk/converter"
+)
+
+func DynamicActivity(ctx context.Context, args converter.EncodedValues) (string, error) {
+	var arg1, arg2 string
+	err := args.Get(&arg1, &arg2)
+	if err != nil {
+		return "", fmt.Errorf("failed to decode arguments: %w", err)
+	}
+
+	info := activity.GetInfo(ctx)
+	result := fmt.Sprintf("%s - %s - %s", info.WorkflowType.Name, arg1, arg2)
+	return result, nil
+}

dynamic-workflows/starter/main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"context"
+	"log"
+
+	"github.com/pborman/uuid"
+	"go.temporal.io/sdk/client"
+)
+
+func main() {
+	// The client is a heavyweight object that should be created once per process.
+	c, err := client.Dial(client.Options{
+		HostPort: client.DefaultHostPort,
+	})
+	if err != nil {
+		log.Fatalln("Unable to create client", err)
+	}
+	defer c.Close()
+
+	// This workflow ID can be user business logic identifier as well.
+	workflowID := "dynamic_workflows_" + uuid.New()
+	workflowOptions := client.StartWorkflowOptions{
+		ID:        workflowID,
+		TaskQueue: "dynamic-workflows",
+	}
+
+	we, err := c.ExecuteWorkflow(context.Background(), workflowOptions, "DurableExecution", "Hello", "Temporal")
+	if err != nil {
+		log.Fatalln("Unable to execute workflow", err)
+	}
+	log.Println("Started workflow", "WorkflowID", we.GetID(), "RunID", we.GetRunID())
+
+	var result string
+	err = we.Get(context.Background(), &result)
+	if err != nil {
+		log.Fatalln("Unable get workflow result", err)
+	}
+	log.Println("Workflow result:", result)
+
+	we, err = c.ExecuteWorkflow(context.Background(), workflowOptions, "dynamic-activity", "Peanut", "Butter")
+	if err != nil {
+		log.Fatalln("Unable to execute workflow", err)
+	}
+	log.Println("Started workflow", "WorkflowID", we.GetID(), "RunID", we.GetRunID())
+
+	err = we.Get(context.Background(), &result)
+	if err != nil {
+		log.Fatalln("Unable get workflow result", err)
+	}
+	log.Println("Workflow result:", result)
+
+	we, err = c.ExecuteWorkflow(context.Background(), workflowOptions, "dynamic-activity123", "Jelly", "Time")
+	if err != nil {
+		log.Fatalln("Unable to execute workflow", err)
+	}
+	log.Println("Started workflow", "WorkflowID", we.GetID(), "RunID", we.GetRunID())
+
+	err = we.Get(context.Background(), &result)
+	if err != nil {
+		log.Fatalln("Unable get workflow result", err)
+	}
+	log.Println("Workflow result:", result)
+}

dynamic-workflows/worker/main.go

@@ -0,0 +1,33 @@
+package main
+
+import (
+	"go.temporal.io/sdk/activity"
+	"go.temporal.io/sdk/workflow"
+	"log"
+
+	"go.temporal.io/sdk/client"
+	"go.temporal.io/sdk/worker"
+
+	dynamic "github.com/temporalio/samples-go/dynamic-workflows"
+)
+
+func main() {
+	// The client and worker are heavyweight objects that should be created once per process.
+	c, err := client.Dial(client.Options{
+		HostPort: client.DefaultHostPort,
+	})
+	if err != nil {
+		log.Fatalln("Unable to create client", err)
+	}
+	defer c.Close()
+
+	w := worker.New(c, "dynamic-workflows", worker.Options{})
+
+	w.RegisterDynamicWorkflow(dynamic.DynamicWorkflow, workflow.DynamicRegisterOptions{})
+	w.RegisterDynamicActivity(dynamic.DynamicActivity, activity.DynamicRegisterOptions{})
+
+	err = w.Run(worker.InterruptCh())
+	if err != nil {
+		log.Fatalln("Unable to start worker", err)
+	}
+}

dynamic-workflows/workflow.go

@@ -0,0 +1,31 @@
+package dynamic_workflows
+
+import (
+	"fmt"
+	"go.temporal.io/sdk/converter"
+	"go.temporal.io/sdk/workflow"
+	"strings"
+	"time"
+)
+
+func DynamicWorkflow(ctx workflow.Context, args converter.EncodedValues) (string, error) {
+	var result string
+	info := workflow.GetInfo(ctx)
+
+	var arg1, arg2 string
+	err := args.Get(&arg1, &arg2)
+	if err != nil {
+		return "", fmt.Errorf("failed to decode arguments: %w", err)
+	}
+
+	if strings.HasPrefix(info.WorkflowType.Name, "dynamic-activity") {
+		ctx = workflow.WithActivityOptions(ctx, workflow.ActivityOptions{StartToCloseTimeout: 10 * time.Second})
+		err := workflow.ExecuteActivity(ctx, "random-activity-name", arg1, arg2).Get(ctx, &result)
+		if err != nil {
+			return "", err
+		}
+	} else {
+		result = fmt.Sprintf("%s - %s - %s", info.WorkflowType.Name, arg1, arg2)
+	}
+	return result, nil
+}