text: // Copyright 2019-2020 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
  //
  //     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.
  
  /**
   * This sample demonstrates how to perform basic operations on topics with
   * the Google Cloud Pub/Sub API.
   *
   * For more information, see the README.md under /pubsub and the documentation
   * at https://cloud.google.com/pubsub/docs.
   */
  
  'use strict';
  
  // sample-metadata:
  //   title: Set Topic IAM Policy
  //   description: Sets the IAM policy for a topic.
  //   usage: node setTopicPolicy.js <topic-name>
  
  function main(topicName = 'YOUR_TOPIC_NAME') {
    // [START pubsub_set_topic_policy]
    /**
     * TODO(developer): Uncomment this variable before running the sample.
     */
    // const topicName = 'YOUR_TOPIC_NAME';
  
    // Imports the Google Cloud client library
    const {PubSub} = require('@google-cloud/pubsub');
  
    // Creates a client; cache this for further use
    const pubSubClient = new PubSub();
  
    async function setTopicPolicy() {
      // The new IAM policy
      const newPolicy = {
        bindings: [
          {
            // Add a group as editors
            role: 'roles/pubsub.editor',
            members: ['group:cloud-logs@google.com'],
          },
          {
            // Add all users as viewers
            role: 'roles/pubsub.viewer',
            members: ['allUsers'],
          },
        ],
      };
  
      // Updates the IAM policy for the topic
      const [updatedPolicy] = await pubSubClient
        .topic(topicName)
        .iam.setPolicy(newPolicy);
      console.log('Updated policy for topic: %j', updatedPolicy.bindings);
    }
  
    setTopicPolicy().catch(console.error);
    // [END pubsub_set_topic_policy]
  }
  
  main(...process.argv.slice(2));
  