Get an IAM policy

Demonstrates retrieving an IAM policy.

Explore further

For detailed documentation that includes this code sample, see the following:

• Manage access to projects, folders, and organizations

Code sample

C++

To learn how to install and use the client library for IAM, see IAM client libraries. For more information, see the IAM C++ API reference documentation.

To authenticate to IAM, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

namespace iam = ::google::cloud::iam_admin_v1;
[](std::string const& name) {
  iam::IAMClient client(iam::MakeIAMConnection());
  auto response = client.GetIamPolicy(name);
  if (!response) throw std::move(response).status();
  std::cout << "Policy successfully retrieved: " << response->DebugString()
            << "\n";
}

C#

To learn how to install and use the client library for IAM, see IAM client libraries. For more information, see the IAM C# API reference documentation.

To authenticate to IAM, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

using Google.Apis.Auth.OAuth2;
using Google.Apis.CloudResourceManager.v1;
using Google.Apis.CloudResourceManager.v1.Data;

public partial class AccessManager
{
    public static Policy GetPolicy(string projectId)
    {
        var credential = GoogleCredential.GetApplicationDefault()
            .CreateScoped(CloudResourceManagerService.Scope.CloudPlatform);
        var service = new CloudResourceManagerService(
            new CloudResourceManagerService.Initializer
            {
                HttpClientInitializer = credential
            });

        var policy = service.Projects.GetIamPolicy(new GetIamPolicyRequest(),
            projectId).Execute();
        return policy;
    }
}

Java

To learn how to install and use the client library for IAM, see IAM client libraries. For more information, see the IAM Java API reference documentation.

To authenticate to IAM, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.json.gson.GsonFactory;
import com.google.api.services.cloudresourcemanager.v3.CloudResourceManager;
import com.google.api.services.cloudresourcemanager.v3.model.GetIamPolicyRequest;
import com.google.api.services.cloudresourcemanager.v3.model.Policy;
import com.google.api.services.iam.v1.IamScopes;
import com.google.auth.http.HttpCredentialsAdapter;
import com.google.auth.oauth2.GoogleCredentials;
import java.io.IOException;
import java.security.GeneralSecurityException;
import java.util.Collections;

public class GetPolicy {

  // Gets a project's policy.
  public static Policy getPolicy(String projectId) {
    // projectId = "my-project-id"

    Policy policy = null;

    CloudResourceManager service = null;
    try {
      service = createCloudResourceManagerService();
    } catch (IOException | GeneralSecurityException e) {
      System.out.println("Unable to initialize service: \n" + e.toString());
      return policy;
    }

    try {
      GetIamPolicyRequest request = new GetIamPolicyRequest();
      policy = service.projects().getIamPolicy(projectId, request).execute();
      System.out.println("Policy retrieved: " + policy.toString());
      return policy;
    } catch (IOException e) {
      System.out.println("Unable to get policy: \n" + e.toString());
      return policy;
    }
  }

  public static CloudResourceManager createCloudResourceManagerService()
      throws IOException, GeneralSecurityException {
    // Use the Application Default Credentials strategy for authentication. For more info, see:
    // https://cloud.google.com/docs/authentication/production#finding_credentials_automatically
    GoogleCredentials credential =
        GoogleCredentials.getApplicationDefault()
            .createScoped(Collections.singleton(IamScopes.CLOUD_PLATFORM));

    CloudResourceManager service =
        new CloudResourceManager.Builder(
                GoogleNetHttpTransport.newTrustedTransport(),
                GsonFactory.getDefaultInstance(),
                new HttpCredentialsAdapter(credential))
            .setApplicationName("service-accounts")
            .build();
    return service;
  }
}

Python

To learn how to install and use the client library for IAM, see IAM client libraries. For more information, see the IAM Python API reference documentation.

To authenticate to IAM, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

def get_policy(project_id: str, version: int = 1) -> dict:
    """Gets IAM policy for a project."""

    credentials = service_account.Credentials.from_service_account_file(
        filename=os.environ["GOOGLE_APPLICATION_CREDENTIALS"],
        scopes=["https://www.googleapis.com/auth/cloud-platform"],
    )
    service = googleapiclient.discovery.build(
        "cloudresourcemanager", "v1", credentials=credentials
    )
    policy = (
        service.projects()
        .getIamPolicy(
            resource=project_id,
            body={"options": {"requestedPolicyVersion": version}},
        )
        .execute()
    )
    print(policy)
    return policy

What's next

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