Async activity Invocation Example in Go

README.md

@@ -186,6 +186,9 @@ These samples demonstrate some common control flow patterns using Temporal's Go
 - [**Sticky task queue for activities**](./activities-sticky-queues): Demonstrates how
   to create a sticky task queue to run certain activities on the same host.
 
+- [**Async activities invocation**](./activities-async): Demonstrates how to invoke two activities in parallel and 
+  return when both of them have completed without blocking between one activity invocation and the following one
+
 ### Scenario based examples
 
 - [**DSL Workflow**](./dsl): Demonstrates how to implement a
@@ -222,7 +225,6 @@ resource waiting its successful completion
 
 Mostly examples we haven't yet ported from https://github.com/temporalio/samples-java/
 
-- Async activity calling: *Example to be completed*
 - Async lambda:  *Example to be completed*
 - Periodic Workflow: Workflow that executes some logic periodically. *Example to be completed*
 - Exception propagation and wrapping: *Example to be completed*

activities-async/README.md

@@ -0,0 +1,19 @@
+# Async Activities Invocation in GoLang
+
+This sample shows how to submit two activities in non-blocking fashion and wait until both are completed to return,
+or fail if one of the two fails. The example uses two activity invocation, registers that on a selector, and invoke
+`selector.Select(ctx)` twice, since each selector call will proceed as soon as one result is available.
+
+
+
+### Running this sample
+
+```bash
+go run activities-async/worker/main.go
+```
+
+Start the Workflow Execution:
+
+```bash
+go run activities-async/starter/main.go
+```

activities-async/activities.go

@@ -0,0 +1,13 @@
+package activities_async
+
+import (
+	"context"
+)
+
+func SayHello(ctx context.Context, param string) (string, error) {
+	return "Hello " + param + "!", nil
+}
+
+func SayGoodbye(ctx context.Context, param string) (string, error) {
+	return "Goodbye " + param + "!", nil
+}

activities-async/starter/main.go

@@ -0,0 +1,37 @@
+package main
+
+import (
+	"context"
+	activities_async "github.com/temporalio/samples-go/activities-async"
+	"log"
+
+	"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{})
+	if err != nil {
+		log.Fatalln("Unable to create client", err)
+	}
+	defer c.Close()
+
+	workflowOptions := client.StartWorkflowOptions{
+		TaskQueue: "async-activities-task-queue",
+	}
+
+	we, err := c.ExecuteWorkflow(context.Background(), workflowOptions, activities_async.AsyncActivitiesWorkflow)
+	if err != nil {
+		log.Fatalln("Unable to execute workflow", err)
+	}
+
+	log.Println("Started workflow", "WorkflowID", we.GetID(), "RunID", we.GetRunID())
+
+	// Synchronously wait for the workflow completion.
+	var result string
+	err = we.Get(context.Background(), &result)
+	if err != nil {
+		log.Fatalln("Unable get workflow result", err)
+	}
+	log.Println("Workflow completed with result ", result)
+}

activities-async/worker/main.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	activities_async "github.com/temporalio/samples-go/activities-async"
+	"log"
+
+	"go.temporal.io/sdk/client"
+	"go.temporal.io/sdk/worker"
+)
+
+func main() {
+	// The client and worker are heavyweight objects that should be created once per process.
+	c, err := client.Dial(client.Options{})
+	if err != nil {
+		log.Fatalln("Unable to create client", err)
+	}
+	defer c.Close()
+	w := worker.New(c, "async-activities-task-queue", worker.Options{})
+	w.RegisterWorkflow(activities_async.AsyncActivitiesWorkflow)
+
+	w.RegisterActivity(activities_async.SayHello)
+	w.RegisterActivity(activities_async.SayGoodbye)
+	err = w.Run(worker.InterruptCh())
+	if err != nil {
+		log.Fatalln("Unable to start worker", err)
+	}
+}

activities-async/workflow.go

@@ -0,0 +1,33 @@
+package activities_async
+
+import (
+	"go.temporal.io/sdk/workflow"
+	"time"
+)
+
+func AsyncActivitiesWorkflow(ctx workflow.Context) (res string, err error) {
+	selector := workflow.NewSelector(ctx)
+	var res1 string
+	var res2 string
+	ao := workflow.ActivityOptions{
+		StartToCloseTimeout: 10 * time.Second,
+	}
+	ctx = workflow.WithActivityOptions(ctx, ao)
+	fut1 := workflow.ExecuteActivity(ctx, SayHello, "Temporal")
+	fut2 := workflow.ExecuteActivity(ctx, SayGoodbye, "Temporal")
+	selector.AddFuture(fut1, func(future workflow.Future) {
+		err = future.Get(ctx, &res1)
+	})
+	selector.AddFuture(fut2, func(future workflow.Future) {
+		err = future.Get(ctx, &res2)
+	})
+	selector.Select(ctx)
+	if err != nil {
+		return
+	}
+	selector.Select(ctx)
+	if err == nil {
+		res = res1 + " It was great to meet you, but time has come. " + res2
+	}
+	return
+}

activities-async/workflow_test.go

@@ -0,0 +1,47 @@
+package activities_async
+
+import (
+	"context"
+	"errors"
+	"github.com/stretchr/testify/mock"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.temporal.io/sdk/testsuite"
+)
+
+func Test_Workflow_Succeeds(t *testing.T) {
+	testSuite := &testsuite.WorkflowTestSuite{}
+	env := testSuite.NewTestWorkflowEnvironment()
+
+	env.RegisterActivity(SayHello)
+	env.RegisterActivity(SayGoodbye)
+	env.ExecuteWorkflow(AsyncActivitiesWorkflow)
+
+	require.True(t, env.IsWorkflowCompleted())
+	require.NoError(t, env.GetWorkflowError())
+	var res string
+	err := env.GetWorkflowResult(&res)
+	require.NoError(t, err)
+	require.Equal(t, "Hello Temporal! It was great to meet you, but time has come. Goodbye Temporal!", res)
+}
+
+func testWorkflowFailsWhenActivityFail(t *testing.T, a interface{}) {
+	testSuite := &testsuite.WorkflowTestSuite{}
+	env := testSuite.NewTestWorkflowEnvironment()
+	env.RegisterActivity(SayHello)
+	env.RegisterActivity(SayGoodbye)
+	env.OnActivity(a, mock.Anything, mock.Anything).Return(func(ctx context.Context, arg string) (string, error) {
+		return "", errors.New("activity failed")
+	})
+	env.ExecuteWorkflow(AsyncActivitiesWorkflow)
+	require.True(t, env.IsWorkflowCompleted())
+	require.Error(t, env.GetWorkflowError())
+}
+
+func Test_Workflow_FailsIfSayHelloFails(t *testing.T) {
+	testWorkflowFailsWhenActivityFail(t, SayHello)
+}
+func Test_Workflow_FailsIfSayGoodbyeFails(t *testing.T) {
+	testWorkflowFailsWhenActivityFail(t, SayGoodbye)
+}