AWS made a serverless option of AWS RDS Aurora generally available, It would mean a breakthrough in building fully serverless architectures with relational database. No more managing connection pools with SQL, No more worrying about RDS instances, Cost is based on the compute time services are consumed, and there is no charge when code is not running. In this post , my goal was to build a fully-functional AWS AppSync-driven backend and React frontend of a post management app. The app will deliver end users a set of features that allow public users view posts, admin users add/delete post, Let’s start! Application Architecture The application architecture uses: Serverless framework AWS Appsync AWS Cognito Userpool and Identity Pool AWS Aurora Serverless AWS Lambda Prerequisites The following must be done before following this guide: Setup an AWS account Install the AWS CLI Configure the AWS CLI with user credentials Install the Serverless framework from NPM $ npm install -g serverless Backend Create a new service Create a new service using the AWS Python template, specifying a unique name and an optional path. $ sls create --template aws-nodejs --path simpleCMS In the app folder, there is a serverless.yml file. This file is needed to configure how our application will behave. Configuring Appsync Install serverless-appsync-plugin npm install serverless-appsync-plugin Add serverless-appsync-plugin to the plugins section of serverless.yml plugins: - serverless-appsync-plugin Add the following config to the custom section of serverless.yml custom: appSync: region: ${self:provider.region} name: ${self:service.name}-${self:provider.stage} authenticationType: AWS_IAM serviceRole: "${self:service.name}-AppSyncServiceRole" userPoolConfig: awsRegion: "${self:provider.region}" userPoolId: ${self:custom.userPool.${self:provider.stage}} defaultAction: ALLOW mappingTemplates: - type: Query dataSource: LambdaSource field: getPosts request: "Query-getPosts-request.vtl" response: "Query-getPosts-response.vtl" - type: Post dataSource: LambdaSource field: author request: "Query-author-request.vtl" response: "Query-author-response.vtl" - type: Mutation field: addPost request: Mutation-addPost-request.vtl response: common-response.vtl kind: PIPELINE functions: - addPost - sendNotification - type: Mutation dataSource: LambdaSource field: deletePost request: Mutation-deletePost-request.vtl response: common-response.vtl functionConfigurations: - dataSource: LambdaSource name: "addPost" request: "Function-addPost-request.vtl" response: "common-response.vtl" - dataSource: LambdaSource name: "sendNotification" request: "Function-sendNotification-request.vtl" response: "Function-sendNotification-response.vtl" dataSources: - type: AWS_LAMBDA name: LambdaSource description: "Lambda DataSource" config: functionName: graphql lambdaFunctionArn: { Fn::GetAtt: [GraphqlLambdaFunction, Arn] } serviceRoleArn: { Fn::GetAtt: [AppSyncLambdaServiceRole, Arn] } You can get all mapping templates from GitHub repo . Next, create a IAM service role for Appsync: <a href="https://medium.com/media/c0c0586f44892991396b65c048873c69/href">https://medium.com/media/c0c0586f44892991396b65c048873c69/href</a> Configuring Cognito Add following config to resources section in serverless.yml <a href="https://medium.com/media/202cba04079fc980dbef56a9acb045f0/href">https://medium.com/media/202cba04079fc980dbef56a9acb045f0/href</a> Note that above config would create a Cognito identity pool supports both authenticated and unauthenticated users, then a system admin user will be added to Cognito user pool and send out an email with temporary password to provided email address, eg. InitialSystemAdminUser: Type: AWS::Cognito::UserPoolUser Properties: UserPoolId: Ref: CognitoUserPool Username: "test@neami.app" DesiredDeliveryMediums: - EMAIL ForceAliasCreation: true UserAttributes: - Name: email Value: "test@neami.app" - Name: name Value: Admin Configuring RDS Aurora Serverless To setup RDS Aurora Serverless, we also need to create a VPC and at least 2 subnets to database, config should like as below <a href="https://medium.com/media/a00a761b8968bb7d58a1e68462e8f823/href">https://medium.com/media/a00a761b8968bb7d58a1e68462e8f823/href</a> To link Appsync lambda datasource to RDS, you will need to add Aurora RDS’ VPC config we just configured to section providers provider: vpc: securityGroupIds: - Fn::GetAtt: [DatabaseVpcSecurityGroup, GroupId] subnetIds: - Ref: PrivateSubnet1 - Ref: PrivateSubnet2 You can find full serverless.yml . here Designing Graphql Schema Schema files are text files, usually named schema.graphql. In this project schema would look like the following <a href="https://medium.com/media/7f9316be3c4eba08176931df6b3661c2/href">https://medium.com/media/7f9316be3c4eba08176931df6b3661c2/href</a> Adding Lambda function Now, let’s update our handler.js to configure our database connection and do some query, This is how the handler.py file looks like: <a href="https://medium.com/media/bf1dff7136bafac74e635e1ced2a8bfb/href">https://medium.com/media/bf1dff7136bafac74e635e1ced2a8bfb/href</a> That is all about the backend, Let’s deploy the service. Serverless framework makes deployments quick and painless. All you need to do is to run one command: $ sls deploy --stage dev It will automagically provision resources on AWS, package up and push all code to S3 from where it will be sent to the Lambdas. The terminal should show output similar to this React Frontend I assume you already have something loading just using react (create using create-react-app). To execute GraphQL queries from React with AWS AppSync, the following libraries are required: - For Auth and other AWS calls aws-amplify, aws-amplify-react - Wrapper around apollo client which manages communication to graphql api endpoint aws-appsync, aws-appsync-react - Apollo client side library for React framework react-apollo Other apollo libraries like apollo-link-http, apollo-link-state and apollo-cache-inmemory I hope you have found this article useful, You can find complete project in my : GitHub repo yai333/AppsyncServerlessCMS Learn more How to add a cache layer to Appsync API Building a Serverless Data Pipeline with AWS S3 Lamba and DynamoDB End to End Testing React apps with Selenium Python WebDriver Chrome PyTest and CircleCI How to build a React chat app with AWS API Gateway WebSockets, Custom Lambda Authorizer Running Selenium and Headless Chrome on AWS Lambda Layers
