Build Serverless Applications in AWS Mobile Hub with New Cloud Logic and User Sign-in Features

Last month, we showed you how to power a mobile back end using a serverless stack, with your business logic in AWS Lambda and the resulting cloud APIs exposed to your app through Amazon API Gateway. This pattern enables you to create and test mobile cloud APIs backed by business logic functions you develop, all without managing servers or paying for unused capacity. Further, you can share your business logic across your iOS and Android apps.

Today, AWS Mobile Hub is announcing a new Cloud Logic feature that makes it much easier for mobile app developers to implement this pattern, integrate their mobile apps with the resulting cloud APIs, and connect the business logic functions to a range of AWS services or on-premises enterprise resources. The feature automatically applies access control to the cloud APIs in API Gateway, making it easy to limit access to app users who have authenticated with any of the user sign-in options in Mobile Hub, including two new options that are also launching today:

• Fully managed email- and password-based app sign-in
• SAML-based app sign-in

In this post, we show how you can build a secure mobile back end in just a few minutes using a serverless stack.

Get started with AWS Mobile Hub

We launched Mobile Hub last year to simplify the process of building, testing, and monitoring mobile applications that use one or more AWS services. Use the integrated Mobile Hub console to choose the features you want to include in your app.

With Mobile Hub, you don’t have to be an AWS expert to begin using its powerful back-end features in your app. Mobile Hub then provisions and configures the necessary AWS services on your behalf and creates a working quickstart app for you. This includes IAM access control policies created to save you the effort of provisioning security policies for resources such as Amazon DynamoDB tables and associating those resources with Amazon Cognito.

Get started with Mobile Hub by navigating to it in the AWS console and choosing your features.

New user sign-in options

We are happy to announce that we now support two new user sign-in options that help you authenticate your app users and provide secure access to control to AWS resources.

The Email and Password option lets you easily provision a fully managed user directory for your app in Amazon Cognito, with sign-in parameters that you configure. The SAML Federation option enables you to authenticate app users using existing credentials in your SAML-enabled identity provider, such as Active Directory Federation Service (ADFS). Mobile Hub also provides ready-to-use app flows for sign-up, sign-in, and password recovery codes that you can add to your own app.

Navigate to the User Sign-in tile in Mobile Hub to get started and choose your sign-in providers.

Read more about the user sign-in feature in this blog and in the Mobile Hub documentation.

Enhanced Cloud Logic

We have enhanced the Cloud Logic feature (the right-hand tile in the top row of the above Mobile Hub screenshot), and you can now easily spin up a serverless stack. This enables you to create and test mobile cloud APIs connected to business logic functions that you develop. Previously, you could use Mobile Hub to integrate existing Lambda functions with your mobile app. With the enhanced Cloud Logic feature, you can now easily create Lambda functions, as well as API Gateway endpoints that you invoke from your mobile apps.

The feature automatically applies access control to the resulting REST APIs in API Gateway, making it easy to limit access to users who have authenticated with any of the user sign-in capabilities in Mobile Hub. Mobile Hub also allows you to test your APIs within your project and set up the permissions that your Lambda function needs for connecting to software resources behind a VPC (e.g., business applications or databases), within AWS or on-premises. Finally, you can integrate your mobile app with your cloud APIs using either the quickstart app (as an example) or the mobile app SDK; both are custom-generated to match your APIs. Here’s how it comes together:

Create an API

After you have chosen a sign-in provider, choose Configure more features. Navigate to Cloud Logic in your project and choose Create a new API. You can choose to limit access to your Cloud Logic API to only signed-in app users:

Under the covers, this creates an IAM role for the API that limits access to authenticated, or signed-in, users.

Quickstart app

The resulting quickstart app generated by Mobile Hub allows you to test your APIs and learn how to develop a mobile UX that invokes your APIs:

Multi-stage rollouts

To make it easy to deploy and test your Lambda function quickly, Mobile Hub provisions both your API and the Lambda function in a Development stage, for instance, https://<yoururl>/Development. This is mapped to a Lambda alias of the same name, Development. Lambda functions are versioned, and this alias is always points to the latest version of the Lambda function. This way, changes you make to your Lambda function are immediately reflected when you invoke the corresponding API in API Gateway.

When you are ready to deploy to production, you can create more stages in API Gateway, such as Production. This gives you an endpoint such as https://<yoururl>/Production. Then, create an alias of the same name in Lambda but point this alias to a specific version of your Lambda function (instead of $LATEST). This way, your Production endpoint always points to a known version of your Lambda function.

Summary

In this post, we demonstrated how to use Mobile Hub to create a secure serverless back end for your mobile app in minutes using three new features – enhanced Cloud Logic, email and password-based app sign-in, and SAML-based app sign-in. While it was just a few steps for the developer, Mobile Hub performed several underlying steps automatically–provisioning back-end resources, generating a sample app, and configuring IAM roles and sign-in providers–so you can focus your time on the unique value in your app. Get started today with AWS Mobile Hub.