How Do I Secure API Gateway Authentication With Keycloak for Model Services?

Introduction

Securing an API Gateway is crucial for protecting your model services from unauthorized access. By integrating Keycloak as an identity provider, you can enhance the security of your API Gateway. This guide provides a comprehensive walkthrough on how to set up an AWS API Gateway with Keycloak as the authentication provider. The process involves configuring necessary resources and IAM roles, ensuring that only authenticated requests can access your services.

Step-by-Step Setup Process

1. Setting up AWS API Gateway

Begin by creating an API Gateway REST API. This API will serve as the entry point for your model services.

const example = new aws.apigateway.RestApi("example", {
    name: "example-api",
    description: "API for model services with Keycloak authentication",
});

2. Configuring Resources and Methods

Define a resource within the API Gateway to represent the endpoint for your model services.

const exampleResource = new aws.apigateway.Resource("example_resource", {
    restApi: example.id,
    parentId: example.rootResourceId,
    pathPart: "models",
});

Set up an HTTP method for the resource. This method will be secured using Keycloak authentication.

const exampleMethod = new aws.apigateway.Method("example_method", {
    restApi: example.id,
    resourceId: exampleResource.id,
    httpMethod: "GET",
    authorization: "COGNITO_USER_POOLS",
    authorizerId: exampleAuthorizer.id,
});

3. Integrating Keycloak with API Gateway

To integrate Keycloak, a Cognito User Pool is required as an intermediary. Create a user pool and configure it as an authorizer for your API Gateway.

const exampleUserPool = new aws.cognito.UserPool("example", {name: "example-user-pool"});

const exampleAuthorizer = new aws.apigateway.Authorizer("example", {
    restApi: example.id,
    name: "keycloak-authorizer",
    type: "COGNITO_USER_POOLS",
    identitySource: "method.request.header.Authorization",
    providerArns: [exampleUserPool.arn],
});

4. Defining IAM Roles and Policies

Create an IAM role that allows API Gateway to invoke the authorizer. Attach a policy to this role to enable necessary permissions.

const apiGatewayRole = new aws.iam.Role("api_gateway_role", {
    name: "ApiGatewayRole",
    assumeRolePolicy: JSON.stringify({
        Version: "2012-10-17",
        Statement: [{
            Effect: "Allow",
            Principal: {
                Service: "apigateway.amazonaws.com",
            },
            Action: "sts:AssumeRole",
        }],
    }),
});

const apiGatewayPolicy = new aws.iam.RolePolicy("api_gateway_policy", {
    role: apiGatewayRole.id,
    policy: JSON.stringify({
        Version: "2012-10-17",
        Statement: [{
            Effect: "Allow",
            Action: "execute-api:Invoke",
            Resource: "*",
        }],
    }),
});

5. Deploying the API

Deploy the API Gateway, ensuring that it is ready for production use.

const exampleDeployment = new aws.apigateway.Deployment("example", {
    restApi: example.id,
    stageName: "prod",
}, {
    dependsOn: [exampleMethod],
});

6. Exporting Outputs

Finally, export the API URL and User Pool ARN for verification and use in your application.

export const apiUrl = exampleDeployment.invokeUrl;
export const userPoolArn = exampleUserPool.arn;

Key Points

• Integration: Keycloak is integrated via Cognito User Pools to secure API Gateway.
• IAM Roles: Proper IAM roles and policies are essential for managing access and ensuring security.
• Deployment: The API is deployed and outputs are exported for verification.

Conclusion

In this guide, we’ve demonstrated how to secure an AWS API Gateway using Keycloak for authentication. By following these steps, you can ensure that your model services are protected against unauthorized access, leveraging Keycloak’s robust identity management capabilities. This setup not only secures your API but also provides a scalable solution for managing user access.