Game Highscores

A quick and dirty highscore aws leaderboard for unity games

Important

At this time this project requires you to create a global secondary index on your dynamo db by hand to make the leaderboard be sortable and for the query to work like so:

I plan to implement this into the template to create it at deploy time, but this feature is still in TODO.

Send a payload of the shape:

{
    "username": "Jessie",
    "score": 5001
}

to the API and it will return you a response of the top 10 scores currently stored in the dynamo db

This project contains source code and supporting files for a serverless application that you can deploy with the AWS Serverless Application Model (AWS SAM) command line interface (CLI). It includes the following files and folders:

• src - Code for the application's Lambda function.
• events - Invocation events that you can use to invoke the function.
• __tests__ - Unit tests for the application code.
• template.yaml - A template that defines the application's AWS resources.

The application uses several AWS resources, including Lambda functions, an API Gateway API, and Amazon DynamoDB tables. These resources are defined in the template.yaml file in this project. You can update the template to add AWS resources through the same deployment process that updates your application code.

Deploy the application

The AWS SAM CLI is an extension of the AWS CLI that adds functionality for building and testing Lambda applications. It uses Docker to run your functions in an Amazon Linux environment that matches Lambda. It can also emulate your application's build environment and API.

To use the AWS SAM CLI, you need the following tools:

• AWS SAM CLI - Install the AWS SAM CLI.
• Node.js - Install Node.js 18, including the npm package management tool.
• Docker - Install Docker community edition.

To build and deploy your application for the first time, run the following in your shell:

sam build
sam deploy --guided

The first command will build the source of your application. The second command will package and deploy your application to AWS, with a series of prompts:

• Stack Name: The name of the stack to deploy to CloudFormation. This should be unique to your account and region, and a good starting point would be something matching your project name.
• AWS Region: The AWS region you want to deploy your app to.
• Confirm changes before deploy: If set to yes, any change sets will be shown to you before execution for manual review. If set to no, the AWS SAM CLI will automatically deploy application changes.
• Allow SAM CLI IAM role creation: Many AWS SAM templates, including this example, create AWS IAM roles required for the AWS Lambda function(s) included to access AWS services. By default, these are scoped down to minimum required permissions. To deploy an AWS CloudFormation stack which creates or modifies IAM roles, the CAPABILITY_IAM value for capabilities must be provided. If permission isn't provided through this prompt, to deploy this example you must explicitly pass --capabilities CAPABILITY_IAM to the sam deploy command.
• Save arguments to samconfig.toml: If set to yes, your choices will be saved to a configuration file inside the project, so that in the future you can just re-run sam deploy without parameters to deploy changes to your application.

The API Gateway endpoint API will be displayed in the outputs when the deployment is complete.

Use the AWS SAM CLI to build and test locally

Build your application by using the sam build command.

highscores-aws$ sam build

The AWS SAM CLI installs dependencies that are defined in package.json, creates a deployment package, and saves it in the .aws-sam/build folder.

Test a single function by invoking it directly with a test event. An event is a JSON document that represents the input that the function receives from the event source. Test events are included in the events folder in this project.

Run functions locally and invoke them with the sam local invoke command.

highscores-aws$ sam local invoke putItemFunction --event events/event-post-item.json
highscores-aws$ sam local invoke getAllItemsFunction --event events/event-get-all-items.json

The AWS SAM CLI can also emulate your application's API. Use the sam local start-api command to run the API locally on port 3000.

highscores-aws$ sam local start-api
highscores-aws$ curl http://localhost:3000/

The AWS SAM CLI reads the application template to determine the API's routes and the functions that they invoke. The Events property on each function's definition includes the route and method for each path.

      Events:
        Api:
          Type: Api
          Properties:
            Path: /
            Method: GET

Deploy the updated application.

highscores-aws$ sam build && sam deploy

Open the Applications page of the Lambda console, and choose your application. When the deployment completes, view the application resources on the Overview tab to see the new resource. Then, choose the function to see the updated configuration that specifies the dead-letter queue.

Fetch, tail, and filter Lambda function logs

To simplify troubleshooting, the AWS SAM CLI has a command called sam logs. sam logs lets you fetch logs that are generated by your Lambda function from the command line. In addition to printing the logs on the terminal, this command has several nifty features to help you quickly find the bug.

NOTE: This command works for all Lambda functions, not just the ones you deploy using AWS SAM.

highscores-aws$ sam logs -n putItemFunction --stack-name sam-app --tail

NOTE: This uses the logical name of the function within the stack. This is the correct name to use when searching logs inside an AWS Lambda function within a CloudFormation stack, even if the deployed function name varies due to CloudFormation's unique resource name generation.

You can find more information and examples about filtering Lambda function logs in the AWS SAM CLI documentation.

Unit tests

Tests are defined in the __tests__ folder in this project. Use npm to install the Jest test framework and run unit tests.

highscores-aws$ npm install
highscores-aws$ npm run test

Cleanup

To delete the sample application that you created, use the AWS CLI. Assuming you used your project name for the stack name, you can run the following:

aws cloudformation delete-stack --stack-name highscores-aws

Resources

For an introduction to the AWS SAM specification, the AWS SAM CLI, and serverless application concepts, see the AWS SAM Developer Guide.

Next, you can use the AWS Serverless Application Repository to deploy ready-to-use apps that go beyond Hello World samples and learn how authors developed their applications. For more information, see the AWS Serverless Application Repository main page and the AWS Serverless Application Repository Developer Guide.