feat(pubsub/v2): add single message transform samples

pubsub/subscriptions/create_message_transforms.go

@@ -0,0 +1,68 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package subscriptions
+
+// [START pubsub_create_subscription_with_smt]
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"cloud.google.com/go/pubsub/v2"
+	"cloud.google.com/go/pubsub/v2/apiv1/pubsubpb"
+)
+
+// createSubscriptionWithSMT creates a subscription with a single message transform function applied.
+func createSubscriptionWithSMT(w io.Writer, projectID, topicID, subID string) error {
+	// projectID := "my-project-id"
+	// topicID := "my-topic"
+	// subID := "my-sub"
+	ctx := context.Background()
+	client, err := pubsub.NewClient(ctx, projectID)
+	if err != nil {
+		return fmt.Errorf("pubsub.NewClient: %w", err)
+	}
+	defer client.Close()
+
+	code := `function redactSSN(message, metadata) {
+			const data = JSON.parse(message.data);
+			delete data['ssn'];
+			message.data = JSON.stringify(data);
+			return message;
+		}`
+
+	transform := &pubsubpb.MessageTransform{
+		Transform: &pubsubpb.MessageTransform_JavascriptUdf{
+			JavascriptUdf: &pubsubpb.JavaScriptUDF{
+				FunctionName: "redactSSN",
+				Code:         code,
+			},
+		},
+	}
+
+	sub := &pubsubpb.Subscription{
+		Name:              fmt.Sprintf("projects/%s/subscriptions/%s", projectID, subID),
+		Topic:             fmt.Sprintf("projects/%s/topics/%s", projectID, topicID),
+		MessageTransforms: []*pubsubpb.MessageTransform{transform},
+	}
+	sub, err = client.SubscriptionAdminClient.CreateSubscription(ctx, sub)
+	if err != nil {
+		return fmt.Errorf("CreateSubscription: %w", err)
+	}
+	fmt.Fprintf(w, "Created subscription with message transform: %v\n", sub)
+	return nil
+}
+
+// [END pubsub_create_subscription_with_smt]

pubsub/subscriptions/subscription_test.go

@@ -35,6 +35,8 @@ import (
 	trace "cloud.google.com/go/trace/apiv1"
 	"cloud.google.com/go/trace/apiv1/tracepb"
 	"google.golang.org/api/iterator"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 
 	"github.com/GoogleCloudPlatform/golang-samples/internal/testutil"
 )
@@ -730,3 +732,34 @@ func createOrGetStorageBucket(projectID, bucketID string) error {
 
 	return nil
 }
+
+func TestCreateSubscriptionWithSMT(t *testing.T) {
+	ctx := context.Background()
+	tc := testutil.SystemTest(t)
+	client := setup(t)
+
+	smtSubID := subID + "-smt"
+	smtTopicID := topicID + "-smt"
+	testutil.Retry(t, 10, time.Second, func(r *testutil.R) {
+		_, err := client.TopicAdminClient.CreateTopic(ctx, &pb.Topic{
+			Name: fmt.Sprintf("projects/%s/topics/%s", tc.ProjectID, smtTopicID),
+		})
+		if err != nil {
+			if st, ok := status.FromError(err); !ok || st.Code() != codes.AlreadyExists {
+				r.Errorf("CreateTopic: %v", err)
+			}
+		}
+	})
+
+	testutil.Retry(t, 10, time.Second, func(r *testutil.R) {
+		buf := new(bytes.Buffer)
+		if err := createSubscriptionWithSMT(buf, tc.ProjectID, smtTopicID, smtSubID); err != nil {
+			r.Errorf("failed to create subscription with SMT: %v", err)
+		}
+		got := buf.String()
+		want := "Created subscription with message transform"
+		if !strings.Contains(got, want) {
+			r.Errorf("got: %s, want: %v", got, want)
+		}
+	})
+}

pubsub/topics/create_topic_message_transforms.go

@@ -0,0 +1,67 @@
+// Copyright 2025 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package topics
+
+// [START pubsub_create_topic_with_smt]
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"cloud.google.com/go/pubsub/v2"
+	"cloud.google.com/go/pubsub/v2/apiv1/pubsubpb"
+)
+
+// createTopicWithSMT creates a topic with a single message transform function applied.
+func createTopicWithSMT(w io.Writer, projectID, topicID string) error {
+	// projectID := "my-project-id"
+	// topicID := "my-topic"
+	ctx := context.Background()
+	client, err := pubsub.NewClient(ctx, projectID)
+	if err != nil {
+		return fmt.Errorf("pubsub.NewClient: %w", err)
+	}
+	defer client.Close()
+
+	code := `function redactSSN(message, metadata) {
+			const data = JSON.parse(message.data);
+			delete data['ssn'];
+			message.data = JSON.stringify(data);
+			return message;
+		}`
+	transform := &pubsubpb.MessageTransform{
+		Transform: &pubsubpb.MessageTransform_JavascriptUdf{
+			JavascriptUdf: &pubsubpb.JavaScriptUDF{
+				FunctionName: "redactSSN",
+				Code:         code,
+			},
+		},
+	}
+
+	topic := &pubsubpb.Topic{
+		Name:              fmt.Sprintf("projects/%s/topics/%s", projectID, topicID),
+		MessageTransforms: []*pubsubpb.MessageTransform{transform},
+	}
+
+	topic, err = client.TopicAdminClient.CreateTopic(ctx, topic)
+	if err != nil {
+		return fmt.Errorf("CreateTopic: %w", err)
+	}
+
+	fmt.Fprintf(w, "Created topic with message transform: %v\n", topic)
+	return nil
+}
+
+// [END pubsub_create_topic_with_smt]

pubsub/topics/topics_test.go

@@ -34,6 +34,8 @@ import (
 	"cloud.google.com/go/trace/apiv1/tracepb"
 	"github.com/GoogleCloudPlatform/golang-samples/internal/testutil"
 	"google.golang.org/api/iterator"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 )
 
 var topicID string
@@ -350,6 +352,30 @@ func TestPublishWithCompression(t *testing.T) {
 	}
 }
 
+func TestCreateTopicWithSMT(t *testing.T) {
+	setup(t)
+	tc := testutil.SystemTest(t)
+	smtTopicID := topicID + "-smt"
+	testutil.Retry(t, 10, time.Second, func(r *testutil.R) {
+		buf := new(bytes.Buffer)
+		err := createTopicWithSMT(buf, tc.ProjectID, smtTopicID)
+		if err != nil {
+			st, ok := status.FromError(err)
+			if ok && st.Code() == codes.AlreadyExists {
+				return // This is expected on a retry.
+			}
+			r.Errorf("failed to create topic with SMT: %v", err)
+			return
+		}
+
+		got := buf.String()
+		want := "Created topic with message transform"
+		if !strings.Contains(got, want) {
+			r.Errorf("got %q, want to contain %q", got, want)
+		}
+	})
+}
+
 func createTopic(ctx context.Context, client *pubsub.Client, topicName string) error {
 	_, err := client.TopicAdminClient.CreateTopic(ctx, &pubsubpb.Topic{
 		Name: topicName,