Make data public

This page shows you how to make objects you own readable to everyone on the public internet. To learn how to access data that has been made public, see Accessing Public Data.

When an object is shared publicly, any user with knowledge of the object URI can access the object for as long as the object is public.

Important: You cannot publicly share an object if the bucket it's stored in is subject to public access prevention.

Required roles

In order to get the required permissions for making objects publicly readable, ask your administrator to grant you the following roles for the bucket that contains the data you want to make public:

• To make all objects in a bucket publicly readable: Storage Admin (roles/storage.admin)

• To make individual objects publicly readable: Storage Object Admin (roles/storage.objectAdmin)

  • If you plan on using the Google Cloud console, you'll need the Storage Admin (roles/storage.admin) role instead of the Storage Object Admin role.

These roles contain the permissions required to make objects public. To see the exact permissions that are required, expand the Required permissions section:

Required permissions

• storage.buckets.get
• storage.buckets.getIamPolicy
• storage.buckets.setIamPolicy
• storage.buckets.update
• storage.objects.get
• storage.objects.getIamPolicy
• storage.objects.setIamPolicy
• storage.objects.update

The following permissions are only required for using the Google Cloud console to perform the tasks on this page:

• storage.buckets.list
• storage.objects.list

You might also be able to get these permissions with other predefined roles or custom roles.

For instructions on granting roles on buckets, see Use IAM with buckets.

Make all objects in a bucket publicly readable

To make all objects in a bucket readable to everyone on the public internet, grant the principal allUsers the Storage Object Viewer (roles/storage.objectViewer) role:

Note: The Storage Object Viewer (roles/storage.objectViewer) role includes the permission required to list the objects in the bucket. For a less permissive role that only allows your users to get objects without listing them, grant the Storage Legacy Object Reader (roles/storage.legacyObjectReader) role instead.

Console

1. In the Google Cloud console, go to the Cloud Storage Buckets page.
   

   Go to Buckets

2. In the list of buckets, click the name of the bucket that you want to make public.

3. Select the Permissions tab near the top of the page.

4. In the Permissions section, click the Grant access button.

   The Grant access dialog appears.

5. In the New principals field, enter allUsers.

6. In the Select a role drop down, enter Storage Object Viewer in the filter box and select the Storage Object Viewer from the filtered results.

7. Click Save.

8. Click Allow public access.

Once public access has been granted, Copy URL appears for each object in the public access column. You can click this button to get the public URL for the object.

To learn how to get detailed error information about failed Cloud Storage operations in the Google Cloud console, see Troubleshooting.

Command line

Note: Cloud Shell provisions a temporary virtual machine. If you want to upload objects to Cloud Storage or download objects from Cloud Storage, use a local development environment.

1. In the Google Cloud console, activate Cloud Shell.

   Activate Cloud Shell

   At the bottom of the Google Cloud console, a Cloud Shell session starts and displays a command-line prompt. Cloud Shell is a shell environment with the Google Cloud CLI already installed and with values already set for your current project. It can take a few seconds for the session to initialize.

2. In your development environment, run the buckets add-iam-policy-binding command:

   gcloud storage buckets add-iam-policy-binding gs://BUCKET_NAME --member=allUsers --role=roles/storage.objectViewer

   Where BUCKET_NAME is the name of the bucket whose objects you want to make public. For example, my-bucket.

Client libraries

C++

For more information, see the Cloud Storage C++ API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

namespace gcs = ::google::cloud::storage;
using ::google::cloud::StatusOr;
[](gcs::Client client, std::string const& bucket_name) {
  auto current_policy = client.GetNativeBucketIamPolicy(
      bucket_name, gcs::RequestedPolicyVersion(3));
  if (!current_policy) throw std::move(current_policy).status();

  current_policy->set_version(3);
  current_policy->bindings().emplace_back(
      gcs::NativeIamBinding("roles/storage.objectViewer", {"allUsers"}));

  auto updated =
      client.SetNativeBucketIamPolicy(bucket_name, *current_policy);
  if (!updated) throw std::move(updated).status();

  std::cout << "Policy successfully updated: " << *updated << "\n";
}

C#

For more information, see the Cloud Storage C# API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

using Google.Apis.Storage.v1.Data;
using Google.Cloud.Storage.V1;
using System;
using System.Collections.Generic;

public class MakeBucketPublicSample
{
    public void MakeBucketPublic(string bucketName = "your-unique-bucket-name")
    {
        var storage = StorageClient.Create();

        Policy policy = storage.GetBucketIamPolicy(bucketName);

        policy.Bindings.Add(new Policy.BindingsData
        {
            Role = "roles/storage.objectViewer",
            Members = new List<string> { "allUsers" }
        });

        storage.SetBucketIamPolicy(bucketName, policy);
        Console.WriteLine(bucketName + " is now public ");
    }
}

Go

For more information, see the Cloud Storage Go API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

import (
	"context"
	"fmt"
	"io"

	"cloud.google.com/go/iam"
	"cloud.google.com/go/iam/apiv1/iampb"
	"cloud.google.com/go/storage"
)

// setBucketPublicIAM makes all objects in a bucket publicly readable.
func setBucketPublicIAM(w io.Writer, bucketName string) error {
	// bucketName := "bucket-name"
	ctx := context.Background()
	client, err := storage.NewClient(ctx)
	if err != nil {
		return fmt.Errorf("storage.NewClient: %w", err)
	}
	defer client.Close()

	policy, err := client.Bucket(bucketName).IAM().V3().Policy(ctx)
	if err != nil {
		return fmt.Errorf("Bucket(%q).IAM().V3().Policy: %w", bucketName, err)
	}
	role := "roles/storage.objectViewer"
	policy.Bindings = append(policy.Bindings, &iampb.Binding{
		Role:    role,
		Members: []string{iam.AllUsers},
	})
	if err := client.Bucket(bucketName).IAM().V3().SetPolicy(ctx, policy); err != nil {
		return fmt.Errorf("Bucket(%q).IAM().SetPolicy: %w", bucketName, err)
	}
	fmt.Fprintf(w, "Bucket %v is now publicly readable\n", bucketName)
	return nil
}

Java

For more information, see the Cloud Storage Java API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

import com.google.cloud.Identity;
import com.google.cloud.Policy;
import com.google.cloud.storage.Storage;
import com.google.cloud.storage.StorageOptions;
import com.google.cloud.storage.StorageRoles;

public class MakeBucketPublic {
  public static void makeBucketPublic(String projectId, String bucketName) {
    // The ID of your GCP project
    // String projectId = "your-project-id";

    // The ID of your GCS bucket
    // String bucketName = "your-unique-bucket-name";

    Storage storage = StorageOptions.newBuilder().setProjectId(projectId).build().getService();
    Policy originalPolicy = storage.getIamPolicy(bucketName);
    storage.setIamPolicy(
        bucketName,
        originalPolicy
            .toBuilder()
            .addIdentity(StorageRoles.objectViewer(), Identity.allUsers()) // All users can view
            .build());

    System.out.println("Bucket " + bucketName + " is now publicly readable");
  }
}

Node.js

For more information, see the Cloud Storage Node.js API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

/**
 * TODO(developer): Uncomment the following lines before running the sample.
 */
// The ID of your GCS bucket
// const bucketName = 'your-unique-bucket-name';

// Imports the Google Cloud client library
const {Storage} = require('@google-cloud/storage');

// Creates a client
const storage = new Storage();

async function makeBucketPublic() {
  await storage.bucket(bucketName).makePublic();

  console.log(`Bucket ${bucketName} is now publicly readable`);
}

makeBucketPublic().catch(console.error);

PHP

For more information, see the Cloud Storage PHP API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

use Google\Cloud\Storage\StorageClient;

/**
 * Update the specified bucket's IAM configuration to make it publicly accessible.
 *
 * @param string $bucketName The name of your Cloud Storage bucket.
 *        (e.g. 'my-bucket')
 */
function set_bucket_public_iam(string $bucketName): void
{
    $storage = new StorageClient();
    $bucket = $storage->bucket($bucketName);

    $policy = $bucket->iam()->policy(['requestedPolicyVersion' => 3]);
    $policy['version'] = 3;

    $role = 'roles/storage.objectViewer';
    $members = ['allUsers'];

    $policy['bindings'][] = [
        'role' => $role,
        'members' => $members
    ];

    $bucket->iam()->setPolicy($policy);

    printf('Bucket %s is now public', $bucketName);
}

Python

For more information, see the Cloud Storage Python API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

from typing import List

from google.cloud import storage


def set_bucket_public_iam(
    bucket_name: str = "your-bucket-name",
    members: List[str] = ["allUsers"],
):
    """Set a public IAM Policy to bucket"""
    # bucket_name = "your-bucket-name"

    storage_client = storage.Client()
    bucket = storage_client.bucket(bucket_name)

    policy = bucket.get_iam_policy(requested_policy_version=3)
    policy.bindings.append(
        {"role": "roles/storage.objectViewer", "members": members}
    )

    bucket.set_iam_policy(policy)

    print(f"Bucket {bucket.name} is now publicly readable")

Ruby

For more information, see the Cloud Storage Ruby API reference documentation.

To authenticate to Cloud Storage, set up Application Default Credentials. For more information, see Set up authentication for client libraries.

def set_bucket_public_iam bucket_name:
  # The ID of your GCS bucket
  # bucket_name = "your-unique-bucket-name"

  require "google/cloud/storage"

  storage = Google::Cloud::Storage.new
  bucket = storage.bucket bucket_name

  bucket.policy do |p|
    p.add "roles/storage.objectViewer", "allUsers"
  end

  puts "Bucket #{bucket_name} is now publicly readable"
end

Terraform

You can use a Terraform resource to make all objects in a bucket public.

# Make bucket public
resource "google_storage_bucket_iam_member" "member" {
  provider = google
  bucket   = google_storage_bucket.default.name
  role     = "roles/storage.objectViewer"
  member   = "allUsers"
}

REST APIs

JSON API

1. Have gcloud CLI installed and initialized, which lets you generate an access token for the Authorization header.

2. Create a JSON file that contains the following information:

   {
     "bindings":[
       {
         "role": "roles/storage.objectViewer",
         "members":["allUsers"]
       }
     ]
   }

3. Use cURL to call the JSON API with a PUT Bucket request:

   curl -X PUT --data-binary @JSON_FILE_NAME \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json" \
     "https://storage.googleapis.com/storage/v1/b/BUCKET_NAME/iam"

   Where:

   • JSON_FILE_NAME is the path for the file that you created in Step 2.
   • BUCKET_NAME is the name of the bucket whose objects you want to make public. For example, my-bucket.

XML API

Making all objects in a bucket publicly readable is not supported by the XML API. Use the Google Cloud console or gcloud storage.

Make a portion of a bucket publicly readable

Important: To complete this task, the target bucket must use uniform bucket-level access. If uniform bucket-level access is disabled for the bucket, you can enable it, or you can use access control lists (ACLs) instead to grant access to individual objects.

Use a managed folder to control access to objects whose name prefix match the name of the managed folder. For example, a managed folder named my-folder can be used to control access to objects named my-folder/cats.jpg and my-folder/dogs.jpg.

To make such objects publicly accessible, first create the managed folder, and then set an IAM policy on the folder that grants allUsers the Storage Object Viewer (roles/storage.objectViewer) role:

Console

1. In the Google Cloud console, go to the Cloud Storage Buckets page.
   

   Go to Buckets

2. Click the name of the bucket that contains the objects you want to make public.

3. Create a folder, using the following steps:

   1. Click the Create folder button.

   2. Enter the Name for the folder. Once the folder is converted to a managed folder, objects whose name start with this name will be subject to IAM roles set on the folder.

   3. Click Create.

4. Convert the folder to a managed folder, using the following steps:

   1. In the pane that shows the bucket's contents, find the name of the folder you created, and click the More options icon .

   2. Click Edit access.

   3. In the window that appears, click Enable.

5. Add an IAM policy to the folder that grants allUsers the Storage Object Viewer (roles/storage.objectViewer) role, using the following steps:

   1. If the Permissions pane for your managed folder isn't already open, click the More options icon for the managed folder, and then click Edit access.

   2. In the Permissions pane, click the Add principal button.

   3. In the New principals field, enter allUsers.

   4. In the Select a role drop down, enter Storage Object Viewer in the filter box, and select Storage Object Viewer from the filtered results.

   5. Click Save.

   6. Click Allow public access.

Once public access has been granted, Copy URL appears for each applicable object in the public access column. You can click this button to get the public URL for the object.

To learn how to get detailed error information about failed Cloud Storage operations in the Google Cloud console, see Troubleshooting.

Command line

Note: Cloud Shell provisions a temporary virtual machine. If you want to upload objects to Cloud Storage or download objects from Cloud Storage, use a local development environment.

1. In the Google Cloud console, activate Cloud Shell.

   Activate Cloud Shell

   At the bottom of the Google Cloud console, a Cloud Shell session starts and displays a command-line prompt. Cloud Shell is a shell environment with the Google Cloud CLI already installed and with values already set for your current project. It can take a few seconds for the session to initialize.

2. In your development environment, create a managed folder using the gcloud storage managed-folders create command:

   gcloud storage managed-folders create gs://BUCKET_NAME/MANAGED_FOLDER_NAME/

   Where:

   • BUCKET_NAME is the name of the bucket in which you want to create a managed folder. For example, my-bucket.

   • MANAGED_FOLDER_NAME is the name of the managed folder you want to create. For example, my-managed-folder.

3. In your development environment, add allUsers to the managed folder's IAM policy using the gcloud storage managed-folders add-iam-policy-binding command:

   gcloud storage managed-folders add-iam-policy-binding gs://BUCKET_NAME/MANAGED_FOLDER_NAME --member=allUsers --role=roles/storage.objectViewer

   Where:

   • BUCKET_NAME is the name of the bucket containing the managed folder you're adding the IAM policy to. For example, my-bucket.
   • MANAGED_FOLDER_NAME is the name of the managed folder that you want to add public access to. For example, my-managed-folder.

REST APIs

JSON API

1. Have gcloud CLI installed and initialized, which lets you generate an access token for the Authorization header.

2. Create a JSON file that contains the following information:

   {
     "name": "MANAGED_FOLDER_NAME"
   }

   Where MANAGED_FOLDER_NAME is the name of the managed folder you want to create. For example, my-managed-folder.

3. Use cURL to call the JSON API with a Insert ManagedFolder request:

   curl -X POST --data-binary @JSON_FILE_NAME \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json" \
     "https://storage.googleapis.com/storage/v1/b/BUCKET_NAME/managedFolders"

   Where:

   • JSON_FILE_NAME is the path for the file that you created in the previous step.
   • BUCKET_NAME is the name of the bucket in which you want to create a managed folder. For example, my-bucket.

4. Create a JSON file that contains the following information:

   {
     "bindings":[
       {
         "role": "roles/storage.objectViewer",
         "members":["allUsers"]
       }
     ]
   }

5. Use cURL to call the JSON API with a setIamPolicy ManagedFolder request:

   curl -X PUT --data-binary @JSON_FILE_NAME \
     -H "Authorization: Bearer $(gcloud auth print-access-token)" \
     -H "Content-Type: application/json" \
     "https://storage.googleapis.com/storage/v1/b/BUCKET_NAME/managedFolders/MANAGED_FOLDER_NAME/iam"

   Where:

   • JSON_FILE_NAME is the path for the file that you created in the previous step.
   • BUCKET_NAME is the name of the bucket containing the managed folder you're adding the IAM policy to. For example, my-bucket.
   • MANAGED_FOLDER_NAME is the name of the managed folder you're adding the IAM policy to. For example, my-managed-folder.

XML API

The XML API does not support working with managed folders. Use a different tool, such as the Google Cloud console, or set ACLs on individual objects using Set Object ACL requests. The following is an example ACL file the would grant allUsers access to an object:

<AccessControlList>
  <Entries>
    <Entry>
      <Scope type="AllUsers"/>
      <Permission>READ</Permission>
    </Entry>
  </Entries>
</AccessControlList>

What's next

• Access data that has been made public.
• Learn about more access control options for your buckets and objects.