[Cloud Tasks] Add task sample with auth token

tasks/README.md

@@ -81,5 +81,15 @@ Running the sample will create a task and send the task to the specific URL
 endpoint, with a payload specified:
 
 ```
-mvn exec:java -Dexec.mainClass="com.example.task.CreateHttpTask"
+mvn exec:java@HttpTask"
+```
+
+### Using HTTP Targets with Authentication Headers
+
+In `CreateHttpTaskWithToken.java`, add your service account email in place of
+`<SERVICE_ACCOUNT_EMAIL>` to authenticate the OIDC token.
+
+Running the sample with command:
+```
+mvn exec:java@WithToken"
 ```

tasks/pom.xml

@@ -54,10 +54,28 @@ Copyright 2018 Google LLC
         <groupId>org.codehaus.mojo</groupId>
         <artifactId>exec-maven-plugin</artifactId>
         <version>1.4.0</version>
-        <configuration>
-          <mainClass>com.example.task.CreateHttpTask</mainClass>
-          <cleanupDaemonThreads>false</cleanupDaemonThreads>
-        </configuration>
+        <executions>
+          <execution>
+              <id>HttpTask</id>
+              <goals>
+                  <goal>java</goal>
+              </goals>
+              <configuration>
+                <mainClass>com.example.task.CreateHttpTask</mainClass>
+                <cleanupDaemonThreads>false</cleanupDaemonThreads>
+              </configuration>
+          </execution>
+          <execution>
+              <id>WithToken</id>
+              <goals>
+                  <goal>java</goal>
+              </goals>
+              <configuration>
+                <mainClass>com.example.task.CreateHttpTaskWithToken</mainClass>
+                <cleanupDaemonThreads>false</cleanupDaemonThreads>
+              </configuration>
+          </execution>
+        </executions>
       </plugin>
     </plugins>
   </build>

tasks/src/main/java/com/example/task/CreateHttpTaskWithToken.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2018 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 com.example.task;
+
+// [START cloud_tasks_create_http_task_with_token]
+import com.google.cloud.tasks.v2beta3.CloudTasksClient;
+import com.google.cloud.tasks.v2beta3.HttpMethod;
+import com.google.cloud.tasks.v2beta3.HttpRequest;
+import com.google.cloud.tasks.v2beta3.OidcToken;
+import com.google.cloud.tasks.v2beta3.QueueName;
+import com.google.cloud.tasks.v2beta3.Task;
+import com.google.protobuf.ByteString;
+import java.nio.charset.Charset;
+
+public class CreateHttpTaskWithToken {
+
+  public static void main(String[] args) throws Exception {
+    String projectId = System.getenv("PROJECT_ID");
+    String queueName = System.getenv("QUEUE_ID");
+    String location = System.getenv("LOCATION_ID");
+    String url = System.getenv("URL");
+
+    // Instantiates a client.
+    try (CloudTasksClient client = CloudTasksClient.create()) {
+      // Variables provided by the system variables.
+      // projectId = "my-project-id";
+      // queueName = "my-appengine-queue";
+      // location = "us-central1";
+      // url = "https://example.com/tasks/create";
+      String payload = "hello";
+
+      // Construct the fully qualified queue name.
+      String queuePath = QueueName.of(projectId, location, queueName).toString();
+
+      // Construct OIDC token
+      OidcToken.Builder oidcTokenBuilder =
+          OidcToken.newBuilder().setServiceAccountEmail("<SERVICE_ACCOUNT_EMAIL>");
+
+      // Construct the task body.
+      Task.Builder taskBuilder =
+          Task.newBuilder()
+              .setHttpRequest(
+                  HttpRequest.newBuilder()
+                      .setBody(ByteString.copyFrom(payload, Charset.defaultCharset()))
+                      .setHttpMethod(HttpMethod.POST)
+                      .setUrl(url)
+                      .setOidcToken(oidcTokenBuilder)
+                      .build());
+
+      // Send create task request.
+      Task task = client.createTask(queuePath, taskBuilder.build());
+      System.out.println("Task created: " + task.getName());
+    }
+  }
+}
+// [END cloud_tasks_create_http_task_with_token]