Grant roles using client libraries

<dependency>
  <groupId>com.google.apis</groupId>
  <artifactId>google-api-services-cloudresourcemanager</artifactId>
  <version>v3-rev20240128-2.0.0</version>
</dependency>
<dependency>
  <groupId>com.google.auth</groupId>
  <artifactId>google-auth-library-oauth2-http</artifactId>
</dependency>
<dependency>
  <groupId>com.google.http-client</groupId>
  <artifactId>google-http-client-jackson2</artifactId>
</dependency>
<dependency>
  <groupId>com.google.apis</groupId>
  <artifactId>google-api-services-iam</artifactId>
  <version>v1-rev20240118-2.0.0</version>
</dependency>

using Google.Apis.Auth.OAuth2;
using Google.Apis.CloudResourceManager.v1;
using Google.Apis.CloudResourceManager.v1.Data;
using Google.Apis.Iam.v1;
using System;
using System.Collections.Generic;
using System.Linq;

public class QuickStart
{
    public static void Main(string[] args)
    {
        // TODO: Replace with your project ID
        var projectId = "your-project";
        // TODO: Replace with the ID of your member in the form "user:[email protected]"
        var member = "your-member";
        // Role to be granted
        var role = "roles/logging.logWriter";

        // Initialize service
        CloudResourceManagerService crmService = InitializeService();

        // Grant your member the "Log Writer" role for your project
        AddBinding(crmService, projectId, member, role);

        // Get the project's policy and print all members with the the "Log Writer" role
        var policy = GetPolicy(crmService, projectId);
        var binding = policy.Bindings.FirstOrDefault(x => x.Role == role);
        Console.WriteLine("Role: " + binding.Role);
        Console.Write("Members: ");
        foreach (var m in binding.Members)
        {
            Console.Write("[" + m + "] ");
        }
        Console.WriteLine();

        // Remove member from the "Log Writer" role
        RemoveMember(crmService, projectId, member, role);
    }

    public static CloudResourceManagerService InitializeService()
    {
        // Get credentials
        var credential = GoogleCredential.GetApplicationDefault()
            .CreateScoped(IamService.Scope.CloudPlatform);

        // Create the Cloud Resource Manager service object
        CloudResourceManagerService crmService = new CloudResourceManagerService(
            new CloudResourceManagerService.Initializer
            {
                HttpClientInitializer = credential
            });

        return crmService;
    }

    public static Policy GetPolicy(CloudResourceManagerService crmService, String projectId)
    {
        // Get the project's policy by calling the
        // Cloud Resource Manager Projects API
        var policy = crmService.Projects.GetIamPolicy(
            new GetIamPolicyRequest(),
            projectId).Execute();
        return policy;
    }

    public static void SetPolicy(CloudResourceManagerService crmService, String projectId, Policy policy)
    {
        // Set the project's policy by calling the
        // Cloud Resource Manager Projects API
        crmService.Projects.SetIamPolicy(
           new SetIamPolicyRequest
           {
               Policy = policy
           }, projectId).Execute();
    }

    public static void AddBinding(
        CloudResourceManagerService crmService,
        string projectId,
        string member,
        string role)
    {
        // Get the project's policy
        var policy = GetPolicy(crmService, projectId);

        // Find binding in policy
        var binding = policy.Bindings.FirstOrDefault(x => x.Role == role);

        // If binding already exists, add member to binding
        if (binding != null)
        {
            binding.Members.Add(member);
        }
        // If binding does not exist, add binding to policy
        else
        {
            binding = new Binding
            {
                Role = role,
                Members = new List<string> { member }
            };
            policy.Bindings.Add(binding);
        }

        // Set the updated policy
        SetPolicy(crmService, projectId, policy);
    }

    public static void RemoveMember(
        CloudResourceManagerService crmService,
        string projectId,
        string member,
        string role)
    {
        // Get the project's policy 
        var policy = GetPolicy(crmService, projectId);

        // Remove the member from the role
        var binding = policy.Bindings.FirstOrDefault(x => x.Role == role);
        if (binding == null)
        {
            Console.WriteLine("Role does not exist in policy.");
        }
        else
        {
            if (binding.Members.Contains(member))
            {
                binding.Members.Remove(member);
            }
            else
            {
                Console.WriteLine("The member has not been granted this role.");
            }

            if (binding.Members.Count == 0)
            {
                policy.Bindings.Remove(binding);
            }
        }

        // Set the updated policy
        SetPolicy(crmService, projectId, policy);
    }
}

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"strings"
	"time"

	"google.golang.org/api/cloudresourcemanager/v1"
)

func main() {
	// TODO: Add your project ID
	projectID := flag.String("project_id", "", "Cloud Project ID")
	// TODO: Add the ID of your member in the form "user:[email protected]"
	member := flag.String("member_id", "", "Your member ID")
	flag.Parse()

	// The role to be granted
	var role string = "roles/logging.logWriter"

	// Initializes the Cloud Resource Manager service
	ctx := context.Background()
	crmService, err := cloudresourcemanager.NewService(ctx)
	if err != nil {
		log.Fatalf("cloudresourcemanager.NewService: %v", err)
	}

	// Grants your member the "Log writer" role for your project
	addBinding(crmService, *projectID, *member, role)

	// Gets the project's policy and prints all members with the "Log Writer" role
	policy := getPolicy(crmService, *projectID)
	// Find the policy binding for role. Only one binding can have the role.
	var binding *cloudresourcemanager.Binding
	for _, b := range policy.Bindings {
		if b.Role == role {
			binding = b
			break
		}
	}
	fmt.Println("Role: ", binding.Role)
	fmt.Print("Members: ", strings.Join(binding.Members, ", "))

	// Removes member from the "Log writer" role
	removeMember(crmService, *projectID, *member, role)

}

// addBinding adds the member to the project's IAM policy
func addBinding(crmService *cloudresourcemanager.Service, projectID, member, role string) {

	policy := getPolicy(crmService, projectID)

	// Find the policy binding for role. Only one binding can have the role.
	var binding *cloudresourcemanager.Binding
	for _, b := range policy.Bindings {
		if b.Role == role {
			binding = b
			break
		}
	}

	if binding != nil {
		// If the binding exists, adds the member to the binding
		binding.Members = append(binding.Members, member)
	} else {
		// If the binding does not exist, adds a new binding to the policy
		binding = &cloudresourcemanager.Binding{
			Role:    role,
			Members: []string{member},
		}
		policy.Bindings = append(policy.Bindings, binding)
	}

	setPolicy(crmService, projectID, policy)

}

// removeMember removes the member from the project's IAM policy
func removeMember(crmService *cloudresourcemanager.Service, projectID, member, role string) {

	policy := getPolicy(crmService, projectID)

	// Find the policy binding for role. Only one binding can have the role.
	var binding *cloudresourcemanager.Binding
	var bindingIndex int
	for i, b := range policy.Bindings {
		if b.Role == role {
			binding = b
			bindingIndex = i
			break
		}
	}

	// Order doesn't matter for bindings or members, so to remove, move the last item
	// into the removed spot and shrink the slice.
	if len(binding.Members) == 1 {
		// If the member is the only member in the binding, removes the binding
		last := len(policy.Bindings) - 1
		policy.Bindings[bindingIndex] = policy.Bindings[last]
		policy.Bindings = policy.Bindings[:last]
	} else {
		// If there is more than one member in the binding, removes the member
		var memberIndex int
		for i, mm := range binding.Members {
			if mm == member {
				memberIndex = i
			}
		}
		last := len(policy.Bindings[bindingIndex].Members) - 1
		binding.Members[memberIndex] = binding.Members[last]
		binding.Members = binding.Members[:last]
	}

	setPolicy(crmService, projectID, policy)

}

// getPolicy gets the project's IAM policy
func getPolicy(crmService *cloudresourcemanager.Service, projectID string) *cloudresourcemanager.Policy {

	ctx := context.Background()

	ctx, cancel := context.WithTimeout(ctx, time.Second*10)
	defer cancel()
	request := new(cloudresourcemanager.GetIamPolicyRequest)
	policy, err := crmService.Projects.GetIamPolicy(projectID, request).Do()
	if err != nil {
		log.Fatalf("Projects.GetIamPolicy: %v", err)
	}

	return policy
}

// setPolicy sets the project's IAM policy
func setPolicy(crmService *cloudresourcemanager.Service, projectID string, policy *cloudresourcemanager.Policy) {

	ctx := context.Background()

	ctx, cancel := context.WithTimeout(ctx, time.Second*10)
	defer cancel()
	request := new(cloudresourcemanager.SetIamPolicyRequest)
	request.Policy = policy
	policy, err := crmService.Projects.SetIamPolicy(projectID, request).Do()
	if err != nil {
		log.Fatalf("Projects.SetIamPolicy: %v", err)
	}
}

import com.google.cloud.iam.admin.v1.IAMClient;
import com.google.iam.admin.v1.ServiceAccountName;
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.protobuf.FieldMask;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Quickstart {

  public static void main(String[] args) throws IOException {
    // TODO: Replace with your project ID.
    String projectId = "your-project";
    // TODO: Replace with your service account name.
    String serviceAccount = "your-service-account";
    // TODO: Replace with the ID of your member in the form "user:[email protected]"
    String member = "your-member";
    // The role to be granted.
    String role = "roles/logging.logWriter";

    quickstart(projectId, serviceAccount, member, role);
  }

  // Creates new policy and adds binding.
  // Checks if changes are present and removes policy.
  public static void quickstart(String projectId, String serviceAccount,
                                String member, String role) throws IOException {

    // Construct the service account email.
    // You can modify the ".iam.gserviceaccount.com" to match the name of the service account
    // to use for authentication.
    serviceAccount = serviceAccount + "@" + projectId + ".iam.gserviceaccount.com";

    // Initialize client that will be used to send requests.
    // This client only needs to be created once, and can be reused for multiple requests.
    try (IAMClient iamClient = IAMClient.create()) {

      // Grants your member the "Log writer" role for your project.
      addBinding(iamClient, projectId, serviceAccount, member, role);

      // Get the project's policy and print all members with the "Log Writer" role
      Policy policy = getPolicy(iamClient, projectId, serviceAccount);

      Binding binding = null;
      List<Binding> bindings = policy.getBindingsList();

      for (Binding b : bindings) {
        if (b.getRole().equals(role)) {
          binding = b;
          break;
        }
      }

      System.out.println("Role: " + binding.getRole());
      System.out.print("Members: ");

      for (String m : binding.getMembersList()) {
        System.out.print("[" + m + "] ");
      }
      System.out.println();

      // Removes member from the "Log writer" role.
      removeMember(iamClient, projectId, serviceAccount, member, role);
    }
  }

  public static void addBinding(IAMClient iamClient, String projectId, String serviceAccount,
                                String member, String role) {
    // Gets the project's policy.
    Policy policy = getPolicy(iamClient, projectId, serviceAccount);

    // If policy is not retrieved, return early.
    if (policy == null) {
      return;
    }

    Policy.Builder updatedPolicy = policy.toBuilder();

    // Get the binding if present in the policy.
    Binding binding = null;
    for (Binding b : updatedPolicy.getBindingsList()) {
      if (b.getRole().equals(role)) {
        binding = b;
        break;
      }
    }

    if (binding != null) {
      // If binding already exists, adds member to binding.
      binding.getMembersList().add(member);
    } else {
      // If binding does not exist, adds binding to policy.
      binding = Binding.newBuilder()
              .setRole(role)
              .addMembers(member)
              .build();
      updatedPolicy.addBindings(binding);
    }

    // Sets the updated policy.
    setPolicy(iamClient, projectId, serviceAccount, updatedPolicy.build());
  }

  public static void removeMember(IAMClient iamClient, String projectId, String serviceAccount,
                                  String member, String role) {
    // Gets the project's policy.
    Policy.Builder policy = getPolicy(iamClient, projectId, serviceAccount).toBuilder();

    // Removes the member from the role.
    Binding binding = null;
    for (Binding b : policy.getBindingsList()) {
      if (b.getRole().equals(role)) {
        binding = b;
        break;
      }
    }

    if (binding != null && binding.getMembersList().contains(member)) {
      List<String> newMemberList = new ArrayList<>(binding.getMembersList());
      newMemberList.remove(member);

      Binding newBinding = binding.toBuilder().clearMembers()
              .addAllMembers(newMemberList)
              .build();
      List<Binding> newBindingList = new ArrayList<>(policy.getBindingsList());
      newBindingList.remove(binding);

      if (!newBinding.getMembersList().isEmpty()) {
        newBindingList.add(newBinding);
      }

      policy.clearBindings()
              .addAllBindings(newBindingList);
    }

    // Sets the updated policy.
    setPolicy(iamClient, projectId, serviceAccount, policy.build());
  }

  public static Policy getPolicy(IAMClient iamClient, String projectId, String serviceAccount) {
    // Gets the project's policy by calling the
    // IAMClient API.
    GetIamPolicyRequest request = GetIamPolicyRequest.newBuilder()
            .setResource(ServiceAccountName.of(projectId, serviceAccount).toString())
            .build();
    return iamClient.getIamPolicy(request);
  }

  private static void setPolicy(IAMClient iamClient, String projectId,
                                String serviceAccount, Policy policy) {
    List<String> paths = Arrays.asList("bindings", "etag");
    // Sets a project's policy.
    SetIamPolicyRequest request = SetIamPolicyRequest.newBuilder()
            .setResource(ServiceAccountName.of(projectId, serviceAccount).toString())
            .setPolicy(policy)
            // A FieldMask specifying which fields of the policy to modify. Only
            // the fields in the mask will be modified. If no mask is provided, the
            // following default mask is used:
            // `paths: "bindings, etag"`
            .setUpdateMask(FieldMask.newBuilder().addAllPaths(paths).build())
            .build();
    iamClient.setIamPolicy(request);
  }
}

from google.cloud import resourcemanager_v3
from google.iam.v1 import iam_policy_pb2, policy_pb2


def quickstart(project_id: str, member: str) -> None:
    """Gets a policy, adds a member, prints their permissions, and removes the member.

    project_id: ID or number of the Google Cloud project you want to use.
    member: The principals requesting the access.
    """

    # Role to be granted.
    role = "roles/logging.logWriter"
    crm_service = resourcemanager_v3.ProjectsClient()

    # Grants your member the 'Log Writer' role for the project.
    modify_policy_add_role(crm_service, project_id, role, member)

    # Gets the project's policy and prints all members with the 'Log Writer' role.
    policy = get_policy(crm_service, project_id)
    binding = next(b for b in policy.bindings if b.role == role)
    print(f"Role: {(binding.role)}")
    print("Members: ")
    for m in binding.members:
        print(f"[{m}]")

    # Removes the member from the 'Log Writer' role.
    modify_policy_remove_member(crm_service, project_id, role, member)


def get_policy(
    crm_service: resourcemanager_v3.ProjectsClient, project_id: str
) -> policy_pb2.Policy:
    """Gets IAM policy for a project."""

    request = iam_policy_pb2.GetIamPolicyRequest()
    request.resource = f"projects/{project_id}"

    policy = crm_service.get_iam_policy(request)
    return policy


def set_policy(
    crm_service: resourcemanager_v3.ProjectsClient,
    project_id: str,
    policy: policy_pb2.Policy,
) -> None:
    """Adds a new role binding to a policy."""

    request = iam_policy_pb2.SetIamPolicyRequest()
    request.resource = f"projects/{project_id}"
    request.policy.CopyFrom(policy)

    crm_service.set_iam_policy(request)


def modify_policy_add_role(
    crm_service: resourcemanager_v3.ProjectsClient,
    project_id: str,
    role: str,
    member: str,
) -> None:
    """Adds a new role binding to a policy."""

    policy = get_policy(crm_service, project_id)

    for bind in policy.bindings:
        if bind.role == role:
            bind.members.append(member)
            break
    else:
        binding = policy_pb2.Binding()
        binding.role = role
        binding.members.append(member)
        policy.bindings.append(binding)

    set_policy(crm_service, project_id, policy)


def modify_policy_remove_member(
    crm_service: resourcemanager_v3.ProjectsClient,
    project_id: str,
    role: str,
    member: str,
) -> None:
    """Removes a  member from a role binding."""

    policy = get_policy(crm_service, project_id)

    for bind in policy.bindings:
        if bind.role == role:
            if member in bind.members:
                bind.members.remove(member)
            break

    set_policy(crm_service, project_id, policy)


if __name__ == "__main__":
    # TODO: replace with your project ID
    project_id = "your-project-id"
    # TODO: Replace with the ID of your member in the form 'user:[email protected]'.
    member = "your-member"
    quickstart(project_id, member)