Ascent Squad API - Products Microservice

Background

This repo contains Sam Pool's System Design Capstone project for the Hack Reactor software engineering immersive program.

This assignment consisted of taking the functionality of an existing monolithic API for a mock e-commerce web app and dissecting it into a microservice architecture with the goal of improving the performance with higher traffic, with each microservice being built by a different developer.

The microservice contained in this repo is the /products endpoint, which returns data about the products available through the e-commerce app - product descriptions, styles, availability, prices, etc.

This microservice was built from scratch in 1.5 weeks.

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Deployment & Performance

To test this microservice's performance with a large dataset, the PostgreSQL database was a seeded with roughly 7 million records.

This microservice was then deployed with the following configuration:

• 4 API Servers
  • Docker images built from this repo
  • AWS EC2 t2 micro instances
• 1 Database Server
  • AWS EC2 t2 micro instances
• 1 Nginx Load Balancer
  • AWS EC2 XXL instance

This configuration was stress tested with LoaderIO, resulting with the following stats from one of the tests:

• 90,000 requests/minute
• 79ms avg request duration
• 0% error rate

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Primary Technologies

This app was built using the following primary technologies:

API Server

• ExpressJS
  • NodeJS framework used to develop the API server.
• PostgreSQL
  • SQL RDMS used for data persistence - accessed via the pg driver package.

Deployment

• Amazon EC2
  • Cloud computing service used to launch multiple API server instances
• Nginx
  • HTTP server used to load balance mutiple API server instances

Testing

• Jest
  • Testing framework, primarily used for testing data model methods and API calls.
• SuperTest
  • Testing library used to make API server calls within Jest.
• k6
  • Testing library used to stress test the app locally
• LoaderIO
  • Developer tool used to stress test the deployed app

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Installation

Steps for getting started as a developer on this repo:

1. Clone this repo onto your local machine:
   • git clone https://github.com/mrsampool/products.git
2. Navigate into the repo's root directory:
   • cd time-tagger
3. Install the project's depencies:
   • npm install
4. For local development, set up a local PostgreSQL database.
   • Once your local database is available, create a db/config.js file exporting your local database connection info as dbConfig.
5. Start developing!

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Provided Scripts

• npm run dev
  • starts a development server which responds to requests from localhost - by default on localhost:3000 - then watches for changes and restarts the server with updated content on each file change.
• npm run test
  • runs the app's full test suite via Jest, automatically running all files with a .test.jsx or test.js file extension.

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Project Structure

• server/

  • files for the ExpressJS API server.
  • app.js
    • The root server file - calls the API router to handle any requests to /api.
    • NOTE: This file does not listen on any port - listening takes place in server/index.js. This seperation allows the app to be tested the supertest module without port conflicts.
    • app.test.js
      • This file is contains integration tests using the supertest library. These tests make requests to different endpoints in the app and check the responses that are returned.
  • index.js
    • This file simply runs the app.js file described above on the port specified by the PORT environment variable or port 3000 if no other port is specified.
    • This is the file which launches this entire app.
  • router.js
    • Exports an express.Router() instance as router which connects the various API routes to their appropriate methods in controller.js.
  • controller.js
    • Exports methods which perform the functionality required to handle the various server requests - i.e. running appropriate methods from the data models (see below) and responding to the requests with the desired data.

• db/

  • files related to the PostgreSQL database
  • models/
    • Data models containing methods for interacting with the database, and tests for the models' methods.
  • index.js
    • connects to a PostgreSQL database using connection info specified in db/config.js (gitignored) and exports the connection as pool.
  • sqlScripts/
    • .sql commands for importing / resetting development data, and a .sh script for running the SQL commands

• etc...

  • config files for jest, etc

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Questions / Comments?

Feel free to reach to developer Sam Pool about this project. I would love to hear from you!

• GitHub: github.com/mrsampool
• LinkedIn: linkedin.com/in/sampool
• Portfolio: sampool.dev
• Email: sambpool@gmail.com