sunheal/retail-q-a

Retail Q&A | Back-end services for e-commerce site

I worked with another software engineer to rebuild back-end API service from a monolithic to service-oriented microservices to support our existing e-commerce application in this project. The service I built was scaled to meet the demands of production traffic which is 1000rps with < 1s response time with 0% error rate.

Technologies used

Backend Development: Node.js, Express, Postgres, NGINX
Deployment: Docker, AWS EC2
Testing: Jest, SuperTest, K6, Loader.io, New Relic

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Table of Contents

• System Design
• Usage
• DB Initialization and ETL Quaries in Postgres
• Installation
• Other Services

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System Design

Database Design

Architecture

Stress Test Results via Loader.io

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Usage

List questions

Retrieves a list of questions for a particular product. This list does not include any reported questions

GET /qa/questions

Query Parameters

Parameter	Type	Description
product_id	integer	Required ID of the question for which data should be returned
page	integer	Selects the page of results to return. Default 1.
count	integer	Specifies how many results per page to return. Default 5

Response: Status: 200 OK

Answers List

Returns answers for a given question. This list does not include any reported answers

GET /qa/questions/:question_id/answers

Query Parameters

Parameter	Type	Description
question_id	integer	Required ID of the question for which answers are needed

Response: Status: 200 OK

Add a Question

Adds a question for the given product

POST /qa/questions

Query Parameters

Parameter	Type	Description
body	text	Text of question being asked
name	text	Username for question asker
email	text	Email address for question asker
product_id	integer	Required ID of the Product for which the question is posted

Response: Status: 201 Created

Mark Question as Helpful

Updates a question to show it was found helpful

PUT /qa/questions/:question_id/helpful

Query Parameters

Parameter	Type	Description
question_id	integer	Required ID of the question to update

Response: Status: 204 NO CONTENT

Report Question

Updates a question to show it was reported. Note, this action does not delete the question, but the question will not be returned in the above GET request

PUT /qa/questions/:question_id/report

Query Parameters

Parameter	Type	Description
question_id	integer	Required ID of the question to update

Response: Status: 204 NO CONTENT

Mark Answer as Helpful

Updates an answer to show it was found helpful

PUT /qa/answers/:answer_id/helpful

Query Parameters

Parameter	Type	Description
answer_id	integer	Required ID of the answer to update

Response: Status: 204 NO CONTENT

Report Answer

Updates an answer to show it has been reported. Note, this action does not delete the answer, but the answer will not be returned in the above GET request

PUT /qa/answers/:answer_id/helpful

Query Parameters

Parameter	Type	Description
answer_id	integer	Required ID of the answer to update

Response: Status: 204 NO CONTENT

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DB Initialization and ETL Quaries in Postgres

1. Run schema.sql
2. Run copyData.sql (if deployed to cloud, run copyData-AWS-EC2.sql instead)
3. Run setPrimarykeySequence.sql
4. Run createIndex.sql
5. After load testing APIs using K6, run deleteK6TestData.sql to delete load test data.

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Installation

1. In the terminal inside, run npm run start to start server
2. Test by typing http://localhost:3000/qa/questions in the Postman to see the response.

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Other Services

Please reference Product Overviews API Services that make up the other part of the e-commerce app API:

• Product Overviews by Xinxin Li