Set topic policy

Sets a topic IAM policy.

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 SetTopicIamPolicySample
{
    public Policy SetTopicIamPolicy(string projectId, string topicId, string role, string member)
    {
        PublisherServiceApiClient publisher = PublisherServiceApiClient.Create();
        string roleToBeAddedToPolicy = $"roles/{role}";

        Policy policy = new Policy
        {
            Bindings = {
                new Binding
                {
                    Role = roleToBeAddedToPolicy,
                    Members = { member }
                }
            }
        };
        SetIamPolicyRequest request = new SetIamPolicyRequest
        {
            ResourceAsResourceName = TopicName.FromProjectTopic(projectId, topicId),
            Policy = policy
        };
        Policy response = publisher.SetIamPolicy(request);
        return response;
    }
}

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"

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

func addUsers(projectID, topicID string) error {
	// projectID := "my-project-id"
	// topicID := "my-topic"
	ctx := context.Background()
	client, err := pubsub.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("pubsub.NewClient: %v", err)
	}

	topic := client.Topic(topicID)
	policy, err := topic.IAM().Policy(ctx)
	if err != nil {
		return fmt.Errorf("Policy: %v", err)
	}
	// Other valid prefixes are "serviceAccount:", "user:"
	// See the documentation for more values.
	policy.Add(iam.AllUsers, iam.Viewer)
	policy.Add("group:cloud-logs@google.com", iam.Editor)
	if err := topic.IAM().SetPolicy(ctx, policy); err != nil {
		return fmt.Errorf("SetPolicy: %v", err)
	}
	// NOTE: It may be necessary to retry this operation if IAM policies are
	// being modified concurrently. SetPolicy will return an error if the policy
	// was modified since it was retrieved.
	return 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.Binding;
import com.google.iam.v1.GetIamPolicyRequest;
import com.google.iam.v1.Policy;
import com.google.iam.v1.SetIamPolicyRequest;
import com.google.pubsub.v1.TopicName;
import java.io.IOException;

public class SetTopicPolicyExample {
  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";

    setTopicPolicyExample(projectId, topicId);
  }

  public static void setTopicPolicyExample(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 oldPolicy = topicAdminClient.getIamPolicy(getIamPolicyRequest);

      // Create new role -> members binding
      Binding binding =
          Binding.newBuilder().setRole("roles/pubsub.editor").addMembers("allUsers").build();

      // Add new binding to updated policy
      Policy updatedPolicy = Policy.newBuilder(oldPolicy).addBindings(binding).build();

      SetIamPolicyRequest setIamPolicyRequest =
          SetIamPolicyRequest.newBuilder()
              .setResource(topicName.toString())
              .setPolicy(updatedPolicy)
              .build();
      Policy newPolicy = topicAdminClient.setIamPolicy(setIamPolicyRequest);
      System.out.println("New topic policy: " + newPolicy);
    }
  }
}

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 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);

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;

/**
 * Adds a user to the policy for a Pub/Sub topic.
 *
 * @param string $projectId  The Google project ID.
 * @param string $topicName  The Pub/Sub topic name.
 * @param string $userEmail  The user email to add to the policy.
 */
function set_topic_policy($projectId, $topicName, $userEmail)
{
    $pubsub = new PubSubClient([
        'projectId' => $projectId,
    ]);
    $topic = $pubsub->topic($topicName);
    $policy = $topic->iam()->policy();
    $policy['bindings'][] = [
        'role' => 'roles/pubsub.publisher',
        'members' => ['user:' . $userEmail]
    ];
    $topic->iam()->setPolicy($policy);

    printf('User %s added to policy for %s' . PHP_EOL,
        $userEmail,
        $topicName);
}

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})

# Add all users as viewers.
policy.bindings.add(role="roles/pubsub.viewer", members=["allUsers"])

# Add a group as a publisher.
policy.bindings.add(
    role="roles/pubsub.publisher", members=["group:cloud-logs@google.com"]
)

# Set the policy
policy = client.set_iam_policy(request={"resource": topic_path, "policy": policy})

print("IAM policy for topic {} set: {}".format(topic_id, policy))

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_name = "Your Pubsub topic name"
# role = "roles/pubsub.publisher"
# service_account_email = "serviceAccount:account_name@project_name.iam.gserviceaccount.com"
require "google/cloud/pubsub"

pubsub = Google::Cloud::Pubsub.new

topic = pubsub.topic topic_name
topic.policy do |policy|
  policy.add role, service_account_email
end