Attach an IAM policy to a role using an Amazon SDK

    /// <summary>
    /// Attach an IAM policy to a role.
    /// </summary>
    /// <param name="policyArn">The policy to attach.</param>
    /// <param name="roleName">The role that the policy will be attached to.</param>
    /// <returns>A Boolean value indicating the success of the action.</returns>
    public async Task<bool> AttachRolePolicyAsync(string policyArn, string roleName)
    {
        var response = await _IAMService.AttachRolePolicyAsync(new AttachRolePolicyRequest
        {
            PolicyArn = policyArn,
            RoleName = roleName,
        });

        return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
    }

###############################################################################
# function errecho
#
# This function outputs everything sent to it to STDERR (standard error output).
###############################################################################
function errecho() {
  printf "%s\n" "$*" 1>&2
}

###############################################################################
# function iam_attach_role_policy
#
# This function attaches an IAM policy to a tole.
#
# Parameters:
#       -n role_name -- The name of the IAM role.
#       -p policy_ARN -- The IAM policy document ARN..
#
# Returns:
#       0 - If successful.
#       1 - If it fails.
###############################################################################
function iam_attach_role_policy() {
  local role_name policy_arn response
  local option OPTARG # Required to use getopts command in a function.

  # bashsupport disable=BP5008
  function usage() {
    echo "function iam_attach_role_policy"
    echo "Attaches an AWS Identity and Access Management (IAM) policy to an IAM role."
    echo "  -n role_name   The name of the IAM role."
    echo "  -p policy_ARN -- The IAM policy document ARN."
    echo ""
  }

  # Retrieve the calling parameters.
  while getopts "n:p:h" option; do
    case "${option}" in
      n) role_name="${OPTARG}" ;;
      p) policy_arn="${OPTARG}" ;;
      h)
        usage
        return 0
        ;;
      \?)
        echo "Invalid parameter"
        usage
        return 1
        ;;
    esac
  done
  export OPTIND=1

  if [[ -z "$role_name" ]]; then
    errecho "ERROR: You must provide a role name with the -n parameter."
    usage
    return 1
  fi

  if [[ -z "$policy_arn" ]]; then
    errecho "ERROR: You must provide a policy ARN with the -p parameter."
    usage
    return 1
  fi

  response=$(aws iam attach-role-policy \
    --role-name "$role_name" \
    --policy-arn "$policy_arn")

  local error_code=${?}

  if [[ $error_code -ne 0 ]]; then
    aws_cli_error_log $error_code
    errecho "ERROR: AWS reports attach-role-policy operation failed.\n$response"
    return 1
  fi

  echo "$response"

  return 0
}

bool AwsDoc::IAM::attachRolePolicy(const Aws::String &roleName,
                                   const Aws::String &policyArn,
                                   const Aws::Client::ClientConfiguration &clientConfig) {
    Aws::IAM::IAMClient iam(clientConfig);

    Aws::IAM::Model::ListAttachedRolePoliciesRequest list_request;
    list_request.SetRoleName(roleName);

    bool done = false;
    while (!done) {
        auto list_outcome = iam.ListAttachedRolePolicies(list_request);
        if (!list_outcome.IsSuccess()) {
            std::cerr << "Failed to list attached policies of role " <<
                      roleName << ": " << list_outcome.GetError().GetMessage() <<
                      std::endl;
            return false;
        }

        const auto &policies = list_outcome.GetResult().GetAttachedPolicies();
        if (std::any_of(policies.cbegin(), policies.cend(),
                        [=](const Aws::IAM::Model::AttachedPolicy &policy) {
                                return policy.GetPolicyArn() == policyArn;
                        })) {
            std::cout << "Policy " << policyArn <<
                      " is already attached to role " << roleName << std::endl;
            return true;
        }

        done = !list_outcome.GetResult().GetIsTruncated();
        list_request.SetMarker(list_outcome.GetResult().GetMarker());
    }

    Aws::IAM::Model::AttachRolePolicyRequest request;
    request.SetRoleName(roleName);
    request.SetPolicyArn(policyArn);

    Aws::IAM::Model::AttachRolePolicyOutcome outcome = iam.AttachRolePolicy(request);
    if (!outcome.IsSuccess()) {
        std::cerr << "Failed to attach policy " << policyArn << " to role " <<
                  roleName << ": " << outcome.GetError().GetMessage() << std::endl;
    }
    else {
        std::cout << "Successfully attached policy " << policyArn << " to role " <<
                  roleName << std::endl;
    }

    return outcome.IsSuccess();
}

// RoleWrapper encapsulates AWS Identity and Access Management (IAM) role actions
// used in the examples.
// It contains an IAM service client that is used to perform role actions.
type RoleWrapper struct {
	IamClient *iam.Client
}



// AttachRolePolicy attaches a policy to a role.
func (wrapper RoleWrapper) AttachRolePolicy(policyArn string, roleName string) error {
	_, err := wrapper.IamClient.AttachRolePolicy(context.TODO(), &iam.AttachRolePolicyInput{
		PolicyArn: aws.String(policyArn),
		RoleName:  aws.String(roleName),
	})
	if err != nil {
		log.Printf("Couldn't attach policy %v to role %v. Here's why: %v\n", policyArn, roleName, err)
	}
	return err
}

    public static void attachIAMRolePolicy(IamClient iam, String roleName, String policyArn ) {

        try {
            ListAttachedRolePoliciesRequest request = ListAttachedRolePoliciesRequest.builder()
                .roleName(roleName)
                .build();

            ListAttachedRolePoliciesResponse response = iam.listAttachedRolePolicies(request);
            List<AttachedPolicy> attachedPolicies = response.attachedPolicies();

            // Ensure that the policy is not attached to this role
            String polArn = "";
            for (AttachedPolicy policy: attachedPolicies) {
                polArn = policy.policyArn();
                if (polArn.compareTo(policyArn)==0) {
                    System.out.println(roleName + " policy is already attached to this role.");
                    return;
                }
            }

           AttachRolePolicyRequest attachRequest = AttachRolePolicyRequest.builder()
               .roleName(roleName)
               .policyArn(policyArn)
               .build();

           iam.attachRolePolicy(attachRequest);

           System.out.println("Successfully attached policy " + policyArn +
                " to role " + roleName);

        } catch (IamException e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
        System.out.println("Done");
    }

Attach the policy.

import { AttachRolePolicyCommand, IAMClient } from "@aws-sdk/client-iam";

const client = new IAMClient({});

/**
 *
 * @param {string} policyArn
 * @param {string} roleName
 */
export const attachRolePolicy = (policyArn, roleName) => {
  const command = new AttachRolePolicyCommand({
    PolicyArn: policyArn,
    RoleName: roleName,
  });

  return client.send(command);
};

// Load the AWS SDK for Node.js
var AWS = require('aws-sdk');
// Set the region 
AWS.config.update({region: 'REGION'});

// Create the IAM service object
var iam = new AWS.IAM({apiVersion: '2010-05-08'});

var paramsRoleList = {
  RoleName: process.argv[2]
};

iam.listAttachedRolePolicies(paramsRoleList, function(err, data) {
  if (err) {
    console.log("Error", err);
  } else {
    var myRolePolicies = data.AttachedPolicies;
    myRolePolicies.forEach(function (val, index, array) {
      if (myRolePolicies[index].PolicyName === 'AmazonDynamoDBFullAccess') {
        console.log("AmazonDynamoDBFullAccess is already attached to this role.")
        process.exit();
      }
    });
    var params = {
      PolicyArn: 'arn:aws:iam::aws:policy/AmazonDynamoDBFullAccess',
      RoleName: process.argv[2]
    };
    iam.attachRolePolicy(params, function(err, data) {
      if (err) {
        console.log("Unable to attach policy to role", err);
      } else {
        console.log("Role attached successfully");
      }
    });
  }
});

suspend fun attachIAMRolePolicy(roleNameVal: String, policyArnVal: String) {

    val request = ListAttachedRolePoliciesRequest {
        roleName = roleNameVal
    }

    IamClient { region = "AWS_GLOBAL" }.use { iamClient ->
        val response = iamClient.listAttachedRolePolicies(request)
        val attachedPolicies = response.attachedPolicies

        // Ensure that the policy is not attached to this role.
        val checkStatus: Int
        if (attachedPolicies != null) {
            checkStatus = checkList(attachedPolicies, policyArnVal)
            if (checkStatus == -1)
                return
        }

        val policyRequest = AttachRolePolicyRequest {
            roleName = roleNameVal
            policyArn = policyArnVal
        }
        iamClient.attachRolePolicy(policyRequest)
        println("Successfully attached policy $policyArnVal to role $roleNameVal")
    }
}

fun checkList(attachedPolicies: List<AttachedPolicy>, policyArnVal: String): Int {

    for (policy in attachedPolicies) {
        val polArn = policy.policyArn.toString()

        if (polArn.compareTo(policyArnVal) == 0) {
            println("The policy is already attached to this role.")
            return -1
        }
    }
    return 0
}

$uuid = uniqid();
$service = new IAMService();

$assumeRolePolicyDocument = "{
                \"Version\": \"2012-10-17\",
                \"Statement\": [{
                    \"Effect\": \"Allow\",
                    \"Principal\": {\"AWS\": \"{$user['Arn']}\"},
                    \"Action\": \"sts:AssumeRole\"
                }]
            }";
$assumeRoleRole = $service->createRole("iam_demo_role_$uuid", $assumeRolePolicyDocument);
echo "Created role: {$assumeRoleRole['RoleName']}\n";

$listAllBucketsPolicyDocument = "{
                \"Version\": \"2012-10-17\",
                \"Statement\": [{
                    \"Effect\": \"Allow\",
                    \"Action\": \"s3:ListAllMyBuckets\",
                    \"Resource\": \"arn:aws:s3:::*\"}]
}";
$listAllBucketsPolicy = $service->createPolicy("iam_demo_policy_$uuid", $listAllBucketsPolicyDocument);
echo "Created policy: {$listAllBucketsPolicy['PolicyName']}\n";

$service->attachRolePolicy($assumeRoleRole['RoleName'], $listAllBucketsPolicy['Arn']);

    public function attachRolePolicy($roleName, $policyArn)
    {
        return $this->customWaiter(function () use ($roleName, $policyArn) {
            $this->iamClient->attachRolePolicy([
                'PolicyArn' => $policyArn,
                'RoleName' => $roleName,
            ]);
        });
    }

Attach a policy to a role using the Boto3 Policy object.

def attach_to_role(role_name, policy_arn):
    """
    Attaches a policy to a role.

    :param role_name: The name of the role. **Note** this is the name, not the ARN.
    :param policy_arn: The ARN of the policy.
    """
    try:
        iam.Policy(policy_arn).attach_role(RoleName=role_name)
        logger.info("Attached policy %s to role %s.", policy_arn, role_name)
    except ClientError:
        logger.exception("Couldn't attach policy %s to role %s.", policy_arn, role_name)
        raise

Attach a policy to a role using the Boto3 Role object.

def attach_policy(role_name, policy_arn):
    """
    Attaches a policy to a role.

    :param role_name: The name of the role. **Note** this is the name, not the ARN.
    :param policy_arn: The ARN of the policy.
    """
    try:
        iam.Role(role_name).attach_policy(PolicyArn=policy_arn)
        logger.info("Attached policy %s to role %s.", policy_arn, role_name)
    except ClientError:
        logger.exception("Couldn't attach policy %s to role %s.", policy_arn, role_name)
        raise

  # Creates a policy that grants permission to list S3 buckets in the account, and
  # then attaches the policy to a role.
  #
  # @param policy_name [String] The name to give the policy.
  # @param role [Aws::IAM::Role] The role that the policy is attached to.
  # @return [Aws::IAM::Policy] The newly created policy.
  def create_and_attach_role_policy(policy_name, role)
    policy = @iam_resource.create_policy(
      policy_name: policy_name,
      policy_document: {
        Version: "2012-10-17",
        Statement: [{
          Effect: "Allow",
          Action: "s3:ListAllMyBuckets",
          Resource: "arn:aws:s3:::*"
        }]
      }.to_json)
    role.attach_policy(policy_arn: policy.arn)
    puts("Created policy #{policy.policy_name} and attached it to role #{role.name}.")
  rescue Aws::Errors::ServiceError => e
    puts("Couldn't create a policy and attach it to role #{role.name}. Here's why: ")
    puts("\t#{e.code}: #{e.message}")
    raise
  else
    policy
  end

pub async fn attach_role_policy(
    client: &iamClient,
    role: &Role,
    policy: &Policy,
) -> Result<AttachRolePolicyOutput, SdkError<AttachRolePolicyError>> {
    client
        .attach_role_policy()
        .role_name(role.role_name.as_ref().unwrap())
        .policy_arn(policy.arn.as_ref().unwrap())
        .send()
        .await
}

    public func attachRolePolicy(role: String, policyArn: String) async throws {
        let input = AttachRolePolicyInput(
            policyArn: policyArn,
            roleName: role
        )
        do {
            _ = try await client.attachRolePolicy(input: input)
        } catch {
            throw error
        }
    }