alexandruantonica/rankings-backend

Server-side client of ISA Rankings (Serverless, NestJS, DynamoDB)

Rankings-Backend

Server-side client of isa-rankings.org

Technical Overview:

• The server-side is entirely designed to be serverless on AWS.
• Requires knowledge on followings
  • Webpack
  • NestJS
  • Typescript
  • Serverless Framework (with Serverless-Offline plugin)
  • AWS DynamoDB (main database)
  • AWS DynamoDB Streams
  • AWS Api Gateway
  • AWS Lambda
  • AWS CloudFormation (infrastructure as a code)
  • AWS IAM Management (user, roles, policies)
  • Redis (read through cache)

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Why serverless?

• Pay as you go: You only pay for the resources you actively use, not when they are sitting idle. Perfect for low|inconsistent traffic applications.
• Costs: Extremely cheap . This application costs less than 1 dolar/month.
• Maintenance & Operation: You never manage infrastructure or any problem that comes with it. Only write the code and it works. Since its a volunteered project nobody wants to do anything but writing the application code

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Architecture Overview

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DynamoDB - (Database Design)

DynamoDB is designed in such a way (primary keys and sort keys) so that it supports all the query patterns this application needs. It has only a single table with aggregated GSIs, hierarchical SKs.

In short, it is customized for application's access patterns.

Overview of the table:

Main Table

PK	SK_GSI	LSI	GSI_SK	...Attributes
Athlete:{id}	AthleteDetails		{normalizedName}	...
Athlete:{id}	Contest:{discipline}:{id}	Contest:{date}	{points}	...
Athlete:{id}	Rankings:{type}:{year}:{discipline}:{gender}:{ageCategory}		{points}	...
Contests	Contest:{discipline}:{id}	Contest:{date}		...

Possible Query Patterns:

• Get details of athlete
• List contests of an athlete sorted by date
• Get a contest of an athlete
• Get a ranking of athlete
• Get details of a contest
• List details of contests sorted by date

GSI Table

GSI	SK	PK	...Attributes
AthleteDetails	{normalizedName}	Athlete:{id}	...
Contest:{discipline}:{id}	{points}	Athlete:{id}	...
Rankings:{year}:{discipline}:{gender}:{ageCategory}	{points}	Athlete:{id}	...

Possible Query Patterns:

• List details of athlete sorted by name
• List athletes of a contest sorted by points
• List athletes of a ranking sorted by points

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Getting Started

To start with, serverless installation must be completed on your local comptuter.

How to: Installation Guide

There are 2 environment stages, therefore you should have valid credentials for them. Checkout the secrets.example.yml under serverless folder. Replace the values with real ones

For deployment aws-cli should be installed and configured with Profiles needed in the serverless.yml file. To get your credentials contact to ISA.

Running on local

First, credentials are obtained from .env file. Replace the values in .env.example file with real ones depending on the stage you want to run (in secrets.yml you can see the stages)

Install dependencies

npm install

Start serverless-offline

npm start

API is served at localhost:3000/

Project Folder Overview

Gource output