samples: create subscription with exactly once delivery enabled (#1032)

* samples: create subscription with exactly once delivery enabled

* lint

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Author: anguillanneuf

java-pubsub/README.md

@@ -245,6 +245,7 @@ Samples are in the [`samples/`](https://github.com/googleapis/java-pubsub/tree/m
 | Create Pull Subscription Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/CreatePullSubscriptionExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/CreatePullSubscriptionExample.java) |
 | Create Push Subscription Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/CreatePushSubscriptionExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/CreatePushSubscriptionExample.java) |
 | Create Subscription With Dead Letter Policy Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/CreateSubscriptionWithDeadLetterPolicyExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/CreateSubscriptionWithDeadLetterPolicyExample.java) |
+| Create Subscription With Exactly Once Delivery | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/CreateSubscriptionWithExactlyOnceDelivery.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/CreateSubscriptionWithExactlyOnceDelivery.java) |
 | Create Subscription With Filtering | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/CreateSubscriptionWithFiltering.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/CreateSubscriptionWithFiltering.java) |
 | Create Subscription With Ordering | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/CreateSubscriptionWithOrdering.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/CreateSubscriptionWithOrdering.java) |
 | Create Topic Example | [source code](https://github.com/googleapis/java-pubsub/blob/main/samples/snippets/src/main/java/pubsub/CreateTopicExample.java) | [![Open in Cloud Shell][shell_img]](https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/googleapis/java-pubsub&page=editor&open_in_editor=samples/snippets/src/main/java/pubsub/CreateTopicExample.java) |

java-pubsub/samples/snippets/src/main/java/pubsub/CreateSubscriptionWithExactlyOnceDelivery.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2022 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
+ *
+ * http://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 pubsub;
+
+// [START pubsub_create_subscription_with_exactly_once_delivery]
+import com.google.cloud.pubsub.v1.SubscriptionAdminClient;
+import com.google.pubsub.v1.ProjectSubscriptionName;
+import com.google.pubsub.v1.ProjectTopicName;
+import com.google.pubsub.v1.Subscription;
+import java.io.IOException;
+
+public class CreateSubscriptionWithExactlyOnceDelivery {
+  public static void main(String... args) throws Exception {
+    // TODO(developer): Replace these variables before running the sample.
+    String projectId = "your-project-id";
+    String topicId = "your-topic-id";
+    String subscriptionId = "your-subscription-id";
+
+    createSubscriptionWithExactlyOnceDeliveryExample(projectId, topicId, subscriptionId);
+  }
+
+  public static void createSubscriptionWithExactlyOnceDeliveryExample(
+      String projectId, String topicId, String subscriptionId) throws IOException {
+    try (SubscriptionAdminClient subscriptionAdminClient = SubscriptionAdminClient.create()) {
+
+      ProjectTopicName topicName = ProjectTopicName.of(projectId, topicId);
+      ProjectSubscriptionName subscriptionName =
+          ProjectSubscriptionName.of(projectId, subscriptionId);
+
+      Subscription subscription =
+          subscriptionAdminClient.createSubscription(
+              Subscription.newBuilder()
+                  .setName(subscriptionName.toString())
+                  .setTopic(topicName.toString())
+                  // Enable exactly once delivery in the subscription.
+                  .setEnableExactlyOnceDelivery(true)
+                  .build());
+
+      System.out.println(
+          "Created a subscription with exactly once delivery enabled: "
+              + subscription.getAllFields());
+    }
+  }
+}
+// [END pubsub_create_subscription_with_exactly_once_delivery]

java-pubsub/samples/snippets/src/test/java/pubsub/AdminIT.java

@@ -45,6 +45,8 @@ public class AdminIT {
   private static final String pushSubscriptionId = "iam-push-subscription-" + _suffix;
   private static final String orderedSubscriptionId = "iam-ordered-subscription-" + _suffix;
   private static final String filteredSubscriptionId = "iam-filtered-subscription-" + _suffix;
+  private static final String exactlyOnceSubscriptionId =
+      "iam-exactly-once-subscription-" + _suffix;
   private static final String pushEndpoint = "https://my-test-project.appspot.com/push";
 
   private static final TopicName topicName = TopicName.of(projectId, topicId);
@@ -56,6 +58,8 @@ public class AdminIT {
       SubscriptionName.of(projectId, orderedSubscriptionId);
   private static final SubscriptionName filteredSubscriptionName =
       SubscriptionName.of(projectId, filteredSubscriptionId);
+  private static final SubscriptionName exactlyOnceSubscriptionName =
+      SubscriptionName.of(projectId, exactlyOnceSubscriptionId);
 
   private static void requireEnvVar(String varName) {
     assertNotNull(
@@ -86,6 +90,7 @@ public void tearDown() throws Exception {
         subscriptionAdminClient.deleteSubscription(pushSubscriptionName);
         subscriptionAdminClient.deleteSubscription(orderedSubscriptionName);
         subscriptionAdminClient.deleteSubscription(filteredSubscriptionName);
+        subscriptionAdminClient.deleteSubscription(exactlyOnceSubscriptionName);
       } catch (NotFoundException ignored) {
         // ignore this as resources may not have been created
       }
@@ -196,10 +201,19 @@ public void testAdmin() throws Exception {
         .contains("google.pubsub.v1.Subscription.filter=attributes.author=\"unknown\"");
 
     bout.reset();
-    // Test delete subscription. Run twice to delete both pull and push subscriptions.
+    // Test create a subscription with exactly once delivery enabled
+    CreateSubscriptionWithExactlyOnceDelivery.createSubscriptionWithExactlyOnceDeliveryExample(
+        projectId, topicId, exactlyOnceSubscriptionId);
+    assertThat(bout.toString())
+        .contains("Created a subscription with exactly once delivery enabled:");
+    assertThat(bout.toString()).contains("enable_exactly_once_delivery=true");
+
+    bout.reset();
+    // Test delete subscription.
     DeleteSubscriptionExample.deleteSubscriptionExample(projectId, pullSubscriptionId);
     DeleteSubscriptionExample.deleteSubscriptionExample(projectId, pushSubscriptionId);
     DeleteSubscriptionExample.deleteSubscriptionExample(projectId, orderedSubscriptionId);
+    DeleteSubscriptionExample.deleteSubscriptionExample(projectId, exactlyOnceSubscriptionId);
     assertThat(bout.toString()).contains("Deleted subscription.");
 
     bout.reset();