Get topic policy

Gets the IAM policy associated with a topic.

Documentation pages that include this code sample

To view the code sample used in context, see the following documentation:

Code sample

C#

Before trying this sample, follow the C# setup instructions in the Pub/Sub quickstart using client libraries. For more information, see the Pub/Sub C# API reference documentation.


using Google.Cloud.Iam.V1;
using Google.Cloud.PubSub.V1;

public class GetTopicIamPolicySample
{
    public Policy GetTopicIamPolicy(string projectId, string topicId)
    {
        PublisherServiceApiClient publisher = PublisherServiceApiClient.Create();
        TopicName topicName = TopicName.FromProjectTopic(projectId, topicId);
        Policy policy = publisher.GetIamPolicy(topicName);
        return policy;
    }
}

Go

Before trying this sample, follow the Go setup instructions in the Pub/Sub quickstart using client libraries. For more information, see the Pub/Sub Go API reference documentation.

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/iam"
	"cloud.google.com/go/pubsub"
)

func policy(w io.Writer, projectID, topicID string) (*iam.Policy, error) {
	// projectID := "my-project-id"
	// topicID := "my-topic"
	ctx := context.Background()
	client, err := pubsub.NewClient(ctx, projectID)
	if err != nil {
		return nil, fmt.Errorf("pubsub.NewClient: %v", err)
	}
	defer client.Close()

	policy, err := client.Topic(topicID).IAM().Policy(ctx)
	if err != nil {
		return nil, fmt.Errorf("Policy: %v", err)
	}
	for _, role := range policy.Roles() {
		fmt.Fprint(w, policy.Members(role))
	}
	return policy, nil
}

Java

Before trying this sample, follow the Java setup instructions in the Pub/Sub quickstart using client libraries. For more information, see the Pub/Sub Java API reference documentation.


import com.google.cloud.pubsub.v1.TopicAdminClient;
import com.google.iam.v1.GetIamPolicyRequest;
import com.google.iam.v1.Policy;
import com.google.pubsub.v1.TopicName;
import java.io.IOException;

public class GetTopicPolicyExample {
  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";

    getTopicPolicyExample(projectId, topicId);
  }

  public static void getTopicPolicyExample(String projectId, String topicId) throws IOException {
    try (TopicAdminClient topicAdminClient = TopicAdminClient.create()) {
      TopicName topicName = TopicName.of(projectId, topicId);
      GetIamPolicyRequest getIamPolicyRequest =
          GetIamPolicyRequest.newBuilder().setResource(topicName.toString()).build();
      Policy policy = topicAdminClient.getIamPolicy(getIamPolicyRequest);
      System.out.println("Topic policy: " + policy);
    }
  }
}

Node.js

Before trying this sample, follow the Node.js setup instructions in the Pub/Sub quickstart using client libraries. For more information, see the Pub/Sub Node.js API reference documentation.

/**
 * 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 getTopicPolicy() {
  // Retrieves the IAM policy for the topic
  const [policy] = await pubSubClient.topic(topicName).iam.getPolicy();
  console.log('Policy for topic: %j.', policy.bindings);
}

getTopicPolicy().catch(console.error);

PHP

Before trying this sample, follow the PHP setup instructions in the Pub/Sub quickstart using client libraries. For more information, see the Pub/Sub PHP API reference documentation.

use Google\Cloud\PubSub\PubSubClient;

/**
 * Prints the policy for a Pub/Sub topic.
 *
 * @param string $projectId  The Google project ID.
 * @param string $topicName  The Pub/Sub topic name.
 */
function get_topic_policy($projectId, $topicName)
{
    $pubsub = new PubSubClient([
        'projectId' => $projectId,
    ]);
    $topic = $pubsub->topic($topicName);
    $policy = $topic->iam()->policy();
    print_r($policy);
}

Python

Before trying this sample, follow the Python setup instructions in the Pub/Sub quickstart using client libraries. For more information, see the Pub/Sub Python API reference documentation.

from google.cloud import pubsub_v1

# TODO(developer): Choose an existing topic.
# project_id = "your-project-id"
# topic_id = "your-topic-id"

client = pubsub_v1.PublisherClient()
topic_path = client.topic_path(project_id, topic_id)

policy = client.get_iam_policy(request={"resource": topic_path})

print("Policy for topic {}:".format(topic_path))
for binding in policy.bindings:
    print("Role: {}, Members: {}".format(binding.role, binding.members))

Ruby

Before trying this sample, follow the Ruby setup instructions in the Pub/Sub quickstart using client libraries. For more information, see the Pub/Sub Ruby API reference documentation.

# topic_id = "your-topic-id"
require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

topic  = pubsub.topic topic_id
policy = topic.policy

puts "Topic policy:"
puts policy.roles

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