Work with the IAM Policy Builder API using an Amazon SDK - Amazon Identity and Access Management
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Work with the IAM Policy Builder API using an Amazon SDK

The following code example shows how to:

  • Create IAM policies by using the object-oriented API.

  • Use the IAM Policy Builder API with the IAM service.

SDK for Java 2.x

There's more on GitHub. Find the complete example and learn how to set up and run in the Amazon Code Examples Repository.

The examples use the following imports.

import org.slf4j.Logger; import org.slf4j.LoggerFactory; import; import; import; import; import; import; import; import; import; import; import; import; import; import; import java.nio.charset.StandardCharsets; import java.util.Arrays; import java.util.List;

Create a time-based policy.

public String timeBasedPolicyExample() { IamPolicy policy = IamPolicy.builder() .addStatement(b -> b .effect(IamEffect.ALLOW) .addAction("dynamodb:GetItem") .addResource(IamResource.ALL) .addCondition(b1 -> b1 .operator(IamConditionOperator.DATE_GREATER_THAN) .key("aws:CurrentTime") .value("2020-04-01T00:00:00Z")) .addCondition(b1 -> b1 .operator(IamConditionOperator.DATE_LESS_THAN) .key("aws:CurrentTime") .value("2020-06-30T23:59:59Z"))) .build(); // Use an IamPolicyWriter to write out the JSON string to a more readable // format. return policy.toJson(IamPolicyWriter.builder() .prettyPrint(true) .build()); }

Create a policy with multiple conditions.

public String multipleConditionsExample() { IamPolicy policy = IamPolicy.builder() .addStatement(b -> b .effect(IamEffect.ALLOW) .addAction("dynamodb:GetItem") .addAction("dynamodb:BatchGetItem") .addAction("dynamodb:Query") .addAction("dynamodb:PutItem") .addAction("dynamodb:UpdateItem") .addAction("dynamodb:DeleteItem") .addAction("dynamodb:BatchWriteItem") .addResource("arn:aws:dynamodb:*:*:table/table-name") .addConditions(IamConditionOperator.STRING_EQUALS .addPrefix("ForAllValues:"), "dynamodb:Attributes", List.of("column-name1", "column-name2", "column-name3")) .addCondition(b1 -> b1 .operator(IamConditionOperator.STRING_EQUALS .addSuffix("IfExists")) .key("dynamodb:Select") .value("SPECIFIC_ATTRIBUTES"))) .build(); return policy.toJson(IamPolicyWriter.builder() .prettyPrint(true).build()); }

Use principals in a policy.

public String specifyPrincipalsExample() { IamPolicy policy = IamPolicy.builder() .addStatement(b -> b .effect(IamEffect.DENY) .addAction("s3:*") .addPrincipal(IamPrincipal.ALL) .addResource("arn:aws:s3:::BUCKETNAME/*") .addResource("arn:aws:s3:::BUCKETNAME") .addCondition(b1 -> b1 .operator(IamConditionOperator.ARN_NOT_EQUALS) .key("aws:PrincipalArn") .value("arn:aws:iam::444455556666:user/user-name"))) .build(); return policy.toJson(IamPolicyWriter.builder() .prettyPrint(true).build()); }

Allow cross-account access.

public String allowCrossAccountAccessExample() { IamPolicy policy = IamPolicy.builder() .addStatement(b -> b .effect(IamEffect.ALLOW) .addPrincipal(IamPrincipalType.AWS, "111122223333") .addAction("s3:PutObject") .addResource("arn:aws:s3:::DOC-EXAMPLE-BUCKET/*") .addCondition(b1 -> b1 .operator(IamConditionOperator.STRING_EQUALS) .key("s3:x-amz-acl") .value("bucket-owner-full-control"))) .build(); return policy.toJson(IamPolicyWriter.builder() .prettyPrint(true).build()); }

Build and upload an IamPolicy.

public String createAndUploadPolicyExample(IamClient iam, String accountID, String policyName) { // Build the policy. IamPolicy policy = IamPolicy.builder() // 'version' defaults to "2012-10-17". .addStatement(IamStatement.builder() .effect(IamEffect.ALLOW) .addAction("dynamodb:PutItem") .addResource("arn:aws:dynamodb:us-east-1:" + accountID + ":table/exampleTableName") .build()) .build(); // Upload the policy. iam.createPolicy(r -> r.policyName(policyName).policyDocument(policy.toJson())); return policy.toJson(IamPolicyWriter.builder().prettyPrint(true).build()); }

Download and work with an IamPolicy.

public String createNewBasedOnExistingPolicyExample(IamClient iam, String accountID, String policyName, String newPolicyName) { String policyArn = "arn:aws:iam::" + accountID + ":policy/" + policyName; GetPolicyResponse getPolicyResponse = iam.getPolicy(r -> r.policyArn(policyArn)); String policyVersion = getPolicyResponse.policy().defaultVersionId(); GetPolicyVersionResponse getPolicyVersionResponse = iam .getPolicyVersion(r -> r.policyArn(policyArn).versionId(policyVersion)); // Create an IamPolicy instance from the JSON string returned from IAM. String decodedPolicy = URLDecoder.decode(getPolicyVersionResponse.policyVersion().document(), StandardCharsets.UTF_8); IamPolicy policy = IamPolicy.fromJson(decodedPolicy); /* * All IamPolicy components are immutable, so use the copy method that creates a * new instance that * can be altered in the same method call. * * Add the ability to get an item from DynamoDB as an additional action. */ IamStatement newStatement = policy.statements().get(0).copy(s -> s.addAction("dynamodb:GetItem")); // Create a new statement that replaces the original statement. IamPolicy newPolicy = policy.copy(p -> p.statements(Arrays.asList(newStatement))); // Upload the new policy. IAM now has both policies. iam.createPolicy(r -> r.policyName(newPolicyName) .policyDocument(newPolicy.toJson())); return newPolicy.toJson(IamPolicyWriter.builder().prettyPrint(true).build()); }

For a complete list of Amazon SDK developer guides and code examples, see Using IAM with an Amazon SDK. This topic also includes information about getting started and details about previous SDK versions.