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Working with IAM Policies

Creating a Policy

To create a new policy, provide the policy’s name and a JSON-formatted policy document in a CreatePolicyRequest to the AmazonIdentityManagementClient’s createPolicy method.

Imports

import com.amazonaws.services.identitymanagement.AmazonIdentityManagement;
import com.amazonaws.services.identitymanagement.AmazonIdentityManagementClientBuilder;
import com.amazonaws.services.identitymanagement.model.CreatePolicyRequest;
import com.amazonaws.services.identitymanagement.model.CreatePolicyResult;

Code

final AmazonIdentityManagement iam =
    AmazonIdentityManagementClientBuilder.defaultClient();

CreatePolicyRequest request = new CreatePolicyRequest()
    .withPolicyName(policy_name)
    .withPolicyDocument(POLICY_DOCUMENT);

CreatePolicyResult response = iam.createPolicy(request);

IAM policy documents are JSON strings with a well-documented syntax. Here is an example that provides access to make particular requests to DynamoDB.

public static final String POLICY_DOCUMENT =
    "{" +
    "  \"Version\": \"2012-10-17\"," +
    "  \"Statement\": [" +
    "    {" +
    "        \"Effect\": \"Allow\"," +
    "        \"Action\": \"logs:CreateLogGroup\"," +
    "        \"Resource\": \"%s\"" +
    "    }," +
    "    {" +
    "        \"Effect\": \"Allow\"," +
    "        \"Action\": [" +
    "            \"dynamodb:DeleteItem\"," +
    "            \"dynamodb:GetItem\"," +
    "            \"dynamodb:PutItem\"," +
    "            \"dynamodb:Scan\"," +
    "            \"dynamodb:UpdateItem\"" +
    "       ]," +
    "       \"Resource\": \"RESOURCE_ARN\"" +
    "    }" +
    "   ]" +
    "}";

See the complete example on GitHub.

Getting a Policy

To retrieve an existing policy, call the AmazonIdentityManagementClient’s getPolicy method, providing the policy’s ARN within a GetPolicyRequest object.

Imports

import com.amazonaws.services.identitymanagement.AmazonIdentityManagement;
import com.amazonaws.services.identitymanagement.AmazonIdentityManagementClientBuilder;
import com.amazonaws.services.identitymanagement.model.GetPolicyRequest;
import com.amazonaws.services.identitymanagement.model.GetPolicyResult;

Code

final AmazonIdentityManagement iam =
    AmazonIdentityManagementClientBuilder.defaultClient();

GetPolicyRequest request = new GetPolicyRequest()
    .withPolicyArn(policy_arn);

GetPolicyResult response = iam.getPolicy(request);

See the complete example on GitHub.

Attaching a Role Policy

You can attach a policy to an IAMhttp://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles.html[role] by calling the AmazonIdentityManagementClient’s attachRolePolicy method, providing it with the role name and policy ARN in an AttachRolePolicyRequest.

Imports

import com.amazonaws.services.identitymanagement.AmazonIdentityManagement;
import com.amazonaws.services.identitymanagement.AmazonIdentityManagementClientBuilder;
import com.amazonaws.services.identitymanagement.model.AttachRolePolicyRequest;
import com.amazonaws.services.identitymanagement.model.AttachedPolicy;

Code

final AmazonIdentityManagement iam =
    AmazonIdentityManagementClientBuilder.defaultClient();

AttachRolePolicyRequest attach_request =
    new AttachRolePolicyRequest()
        .withRoleName(role_name)
        .withPolicyArn(POLICY_ARN);

iam.attachRolePolicy(attach_request);

See the complete example on GitHub.

Listing Attached Role Policies

List attached policies on a role by calling the AmazonIdentityManagementClient’s listAttachedRolePolicies method. It takes a ListAttachedRolePoliciesRequest object that contains the role name to list the policies for.

Call getAttachedPolicies on the returned ListAttachedRolePoliciesResult object to get the list of attached policies. Results may be truncated; if the ListAttachedRolePoliciesResult object’s getIsTruncated method returns true, call the ListAttachedRolePoliciesRequest object’s setMarker method and use it to call listAttachedRolePolicies again to get the next batch of results.

Imports

import com.amazonaws.services.identitymanagement.AmazonIdentityManagement;
import com.amazonaws.services.identitymanagement.AmazonIdentityManagementClientBuilder;
import com.amazonaws.services.identitymanagement.model.ListAttachedRolePoliciesRequest;
import com.amazonaws.services.identitymanagement.model.ListAttachedRolePoliciesResult;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;

Code

final AmazonIdentityManagement iam =
    AmazonIdentityManagementClientBuilder.defaultClient();

ListAttachedRolePoliciesRequest request =
    new ListAttachedRolePoliciesRequest()
        .withRoleName(role_name);

List<AttachedPolicy> matching_policies = new ArrayList<>();

boolean done = false;

while(!done) {
    ListAttachedRolePoliciesResult response =
        iam.listAttachedRolePolicies(request);

    matching_policies.addAll(
            response.getAttachedPolicies()
                    .stream()
                    .filter(p -> p.getPolicyName().equals(role_name))
                    .collect(Collectors.toList()));

    if(!response.getIsTruncated()) {
        done = true;
    }
    request.setMarker(response.getMarker());
}

See the complete example on GitHub.

Detaching a Role Policy

To detach a policy from a role, call the AmazonIdentityManagementClient’s detachRolePolicy method, providing it with the role name and policy ARN in a DetachRolePolicyRequest.

Imports

import com.amazonaws.services.identitymanagement.AmazonIdentityManagement;
import com.amazonaws.services.identitymanagement.AmazonIdentityManagementClientBuilder;
import com.amazonaws.services.identitymanagement.model.DetachRolePolicyRequest;
import com.amazonaws.services.identitymanagement.model.DetachRolePolicyResult;

Code

final AmazonIdentityManagement iam =
    AmazonIdentityManagementClientBuilder.defaultClient();

DetachRolePolicyRequest request = new DetachRolePolicyRequest()
    .withRoleName(role_name)
    .withPolicyArn(policy_arn);

DetachRolePolicyResult response = iam.detachRolePolicy(request);

See the complete example on GitHub.

More Information