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RESTful web API in Java with Spring that provides an HTTP interface for creating and managing game sessions and users.

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Scorekeep

Scorekeep is a RESTful web API implemented in Java that uses Spring to provide an HTTP interface for creating and managing game sessions and users. This project includes the Scorekeep API and a front-end web app that consumes it. The front end and API can run on the same server and domain or separately, with the API running in Elastic Beanstalk and the front end served statically by a CDN.

The fargate branch shows the use of Spring, Angular, nginx, the AWS SDK for Java, Amazon DynamoDB, Gradle, and AWS ECS Fargate features that enable you to:

Other branches extend the application's functionality and show the use of other AWS services. See the readme in each branch for details about the integration and instructions for use.

Branches

  • master - Original AWS Elastic Beanstalk scorekeep application.
  • cognito - Support login and store users in an Amazon Cognito user pool. Get AWS SDK credentials and make service calls with a Cognito identity pool.
  • cognito-basic - Use Cognito for user ID storage. User pool only, no identity pool.
  • lambda - Call an AWS Lambda function to generate random names.
  • lambda-worker - Run a Lambda function periodically to process game records and store the output in Amazon S3.
  • sql - Use JDBC to store game histories in an attached PostgreSQL database instance.
  • xray - Use the AWS X-Ray SDK for Java to instrument incoming requests, functions, SDK clients, SQL queries, HTTP clients, startup code, and AWS Lambda functions.
  • xray-cognito - Use AWS credentials obtained with Amazon Cognito to upload trace data to X-Ray from the browser.
  • xray-gettingstarted (tutorial) - Use the AWS X-Ray SDK for Java to instrument incoming requests and SDK clients (no additional configuration required).
  • xray-worker - Instrumented Python Lambda worker function from the lambda-worker branch.

Use the procedures in the following sections to run the project on Fargate and configure it for local testing and development.

Sections

Prerequisites

Install the following tools to create Docker images, upload them to ECR, and register task definitions with ECS.

  • Docker
  • AWS CLI v1.14.0+
  • AWS user with permission for IAM, DynamoDB, SNS, ECS, CloudWatch Logs, and ECR

Repository Layout

The project contains two independent applications:

  • An HTML and JavaScript front end in Angular 1.5 to be ran with Nginx
  • A Java backend that uses Spring to provide a public API

The backend and frontend are both built using docker and make. Docker images are published to Amazon ECR.

Directory Contents Build Package Publish Clean
/ Contains the Java Backend (aka scorekeep-api) make build make package make publish make clean
/scorekeep-frontend Contains the Angular+Nginx frontend N/A make package make publish N/A
/task-definition Contains template to generata a Task Definition ./generate-task-definition N/A aws ecs register-task-definition --cli-input-json file://scorekeep-task-definition.json N/A
/cloudformation Contains the Cloudformation template for creating the dependant resources (i.e. DynamoDB, SNS, CWL, ECR, and IAM) N/A N/A make stack make clean

Cloudformation setup

The pre-requisite resources can be setup using Cloudformation.

The Cloudformation template requires no paramaters and can be ran by executing make stack from the directory. It will use the AWS_REGION configured in aws.env in the root of the package, and the default credentials from the AWS CLI. IAM permissions are needed for the Cloudformation stack to run successfully.

Building the Java application

The Java application is built using the gradle Docker container so it does not rely on your local Java or Gradle setup. The output of the build process appears in the build/ folder of the project. After you build the application you will want to package it into a docker container so it can be executed. The docker container packaging takes the JAR produced from the build step and adds it to a Java base image. It then configures the environment, ports, and entry point. The docker can be ran locally with valid AWS credentials, or ran on ECS.

Deploying the application

To deploy the containers to your AWS Account

  1. Setup the Cloudformation stack to create the prerequisite resources by executing make stack in the cloudformation/ folder
  2. Build and Publish your API container to the ECR repository created by Cloudformation executing make publish in the root folder
  3. Build and Publish your Frontend container to the ECR repository created by Cloudformation executing make publish in the scorekeep-frontend/ folder
  4. Populate your Task Definition with the correct region and account id using the generate-task-definition script in the task-definition folder
  5. Register your Task Definition to ECS with aws ecs register-task-definition --cli-input-json file://scorekeep-task-definition.json
  6. Launch your Service or Task using the AWS CLI, ECS CLI, or AWS Management Console

To create a Fargate Service for Scorekeep with the ECS console

  1. Open the ECS console.
  2. Click Create cluster.
  3. Select Networking only and click Next step.
  4. Enter scorekeep-cluster for the cluster name and click Create.
  5. Choose View cluster.
  6. Under Services, click Create.
  7. Create a service with the following settings. Click Next Step to proceed through each page as necessary.
  • Launch type: Fargate
  • Task definition: scorekeep:1
  • Platform version: latest
  • Cluster: scorekeep-cluster
  • Service name: scorekeep-service
  • Number of tasks: 4
  • Minimum healthy percent: 50
  • Maximum percent: 200
  • Cluster VPC: scorekeep
  • Subnets: both scorekeep_Private subnets
  • Security groups: click Edit > Select existing > select default
  • Auto-assign public IP: enabled
  • Load balancer type: Application load balancer
  • Load balancer name: scorekeep-lb
  • Container name: scorekeep-frontend (click Add to load balancer)
  • Listener port: 80:HTTP
  • Target group name: Create new
  • Path pattern: /*
  • Health check pattern: /
  • Service auto scaling: Do not adjust
  1. Choose View service.
  2. Open the load balancers screen in the EC2 console.
  3. Choose scorekeep-lb.
  4. Under Description, copy the DNS name and open it.

Scorekeep flow

Click through the app to explore its functionality. Use the network console in your browser to see the HTTP requests that it sends to the API to read and write users, sessions, games, moves, and game state to DynamoDB via the API.

Configuring notifications

The API uses SNS to send a notification email when a game ends. To enable e-mail notifications, to an email address to your Task Definition in environment variable NOTIFICATION_EMAIL. To enable other notifications add the subscription to the topic through the SNS console.

How it works

Backend

The API runs at paths under /api that provide access to user, session, game, state, and move resources stored as JSON documents in DynamoDB. The API is RESTful, so you can create resources by sending HTTP POST requests to the resource path, for example /api/session. See the test script for example requests with cURL.

The Cloudformation template creates a DynamoDB table for each resource type.

Front end

The front end is an Angular 1.5 web app that uses $resource objects to perform CRUD operations on resources defined by the API. Users first encounter the main view and controller and progress through session and game views at routes that include the IDs of resources that the user creates.

The front end is served statically by an Nginx container. The nginx.conf file in the source code sets up Nginx to serve the frontend html pages from root, and forward requests starting with /api to the API backend running on port 5000.

Running the project locally

You can run both the API and front-end locally with Docker To get started, clone this repository.

Run the Scorekeep API with Docker

The API requires DynamoDB tables and SNS topic to exist in AWS to run locally. To create the tables and SNS topic run the Cloudformation template with make stack after setting the desired region in aws.env

After the Cloudformation stack has finished creating execute make run-local in the root directory to start the API container. You can later do docker attach to follow log output or docker ps to view the current state. When running local we use net=host networking mode in Docker as this is most simialr to the awsvpc network mode on ECS.

The application needs AWS credentials to communicate with DynamoDB. In ECS, Scorekeep gets credentials from the task role. When you run the application locally, we will mount in ~/.aws/ to the container where the AWS SDK for Java will retrieve credentials. You can also configure your credentials as environment variables if you prefer.

Follow the instructions in the AWS SDK for Java Developer Guide to provide access keys to the application: Set up AWS Credentials for Development.

Use the test script to verify that the API works.

~/eb-java-scorekeep$ ./bin/test-api.sh

The script targets localhost:5000. However, you can point it at the API running on any hostname or IP by modifying the API variable at the top of the file.

Run the Scorekeep Frontend with Docker

You can run the frontend container locally by executing make run-local from the scorekeep-frontend directory. As with the API container this runs with net=host as the networkmode. You should be able to hit it locally with a web browser or curl on localhost:8080

Contributing

This sample application could be better with your help!