docs(samples): add update credentials (#425)

Author: Praful Makani

samples/snippets/src/main/java/com/example/bigquerydatatransfer/UpdateCredentials.java

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2020 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.bigquerydatatransfer;
+
+// [START bigquerydatatransfer_update_credentials]
+import com.google.api.gax.rpc.ApiException;
+import com.google.cloud.bigquery.datatransfer.v1.DataTransferServiceClient;
+import com.google.cloud.bigquery.datatransfer.v1.TransferConfig;
+import com.google.cloud.bigquery.datatransfer.v1.UpdateTransferConfigRequest;
+import com.google.protobuf.FieldMask;
+import com.google.protobuf.util.FieldMaskUtil;
+import java.io.IOException;
+
+// Sample to update credentials in transfer config.
+public class UpdateCredentials {
+
+  public static void main(String[] args) throws IOException {
+    // TODO(developer): Replace these variables before running the sample.
+    String configId = "MY_CONFIG_ID";
+    String serviceAccount = "MY_SERVICE_ACCOUNT";
+    TransferConfig transferConfig = TransferConfig.newBuilder().setName(configId).build();
+    FieldMask updateMask = FieldMaskUtil.fromString("service_account_name");
+    updateCredentials(transferConfig, serviceAccount, updateMask);
+  }
+
+  public static void updateCredentials(
+      TransferConfig transferConfig, String serviceAccount, FieldMask updateMask)
+      throws IOException {
+    try (DataTransferServiceClient dataTransferServiceClient = DataTransferServiceClient.create()) {
+      UpdateTransferConfigRequest request =
+          UpdateTransferConfigRequest.newBuilder()
+              .setTransferConfig(transferConfig)
+              .setUpdateMask(updateMask)
+              .setServiceAccountName(serviceAccount)
+              .build();
+      dataTransferServiceClient.updateTransferConfig(request);
+      System.out.println("Credentials updated successfully");
+    } catch (ApiException ex) {
+      System.out.print("Credentials was not updated." + ex.toString());
+    }
+  }
+}
+// [END bigquerydatatransfer_update_credentials]

samples/snippets/src/test/java/com/example/bigquerydatatransfer/UpdateCredentialsIT.java

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+/*
+ * Copyright 2020 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.bigquerydatatransfer;
+
+import static com.google.common.truth.Truth.assertThat;
+import static junit.framework.TestCase.assertNotNull;
+
+import com.google.cloud.bigquery.datatransfer.v1.TransferConfig;
+import com.google.protobuf.FieldMask;
+import com.google.protobuf.util.FieldMaskUtil;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.PrintStream;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class UpdateCredentialsIT {
+
+  private static final Logger LOG = Logger.getLogger(UpdateCredentialsIT.class.getName());
+  private ByteArrayOutputStream bout;
+  private PrintStream out;
+  private PrintStream originalPrintStream;
+
+  private static final String CONFIG_NAME = requireEnvVar("DTS_TRANSFER_CONFIG_NAME");
+  private static final String SERVICE_ACCOUNT = requireEnvVar("DTS_UPDATED_SERVICE_ACCOUNT");
+
+  private static String requireEnvVar(String varName) {
+    String value = System.getenv(varName);
+    assertNotNull(
+        "Environment variable " + varName + " is required to perform these tests.",
+        System.getenv(varName));
+    return value;
+  }
+
+  @BeforeClass
+  public static void checkRequirements() {
+    requireEnvVar("DTS_TRANSFER_CONFIG_NAME");
+    requireEnvVar("DTS_UPDATED_SERVICE_ACCOUNT");
+  }
+
+  @Before
+  public void setUp() {
+    bout = new ByteArrayOutputStream();
+    out = new PrintStream(bout);
+    originalPrintStream = System.out;
+    System.setOut(out);
+  }
+
+  @After
+  public void tearDown() {
+    // restores print statements in the original method
+    System.out.flush();
+    System.setOut(originalPrintStream);
+    LOG.log(Level.INFO, bout.toString());
+  }
+
+  @Test
+  public void testUpdateCredentials() throws IOException {
+    TransferConfig transferConfig = TransferConfig.newBuilder().setName(CONFIG_NAME).build();
+    FieldMask updateMask = FieldMaskUtil.fromString("service_account_name");
+    UpdateCredentials.updateCredentials(transferConfig, SERVICE_ACCOUNT, updateMask);
+    assertThat(bout.toString()).contains("Credentials updated successfully");
+  }
+}