Service - About

Coursera About Service Contains a description of the course, along with some strategic goals and possible outcomes of taking the course.

View the sample on Coursera under "About this Course"

Deployment Architecture

Related Projects

• https://github.com/SDC-Builder/Tim-Proxy-Server
• https://github.com/SDC-Builder/Tim-About-Service

Table of Contents

1. Usage
2. CRUD_API
3. API_Performance

Usage

• Run npm install from the root directory to install dependencies
• From within the database directory, run csvCreator.js to generate 10 million records.
• Seed a Cassandra database with database/cassandra/cassandraFiller.js
• Run npm build to build the webpack bundle
• Run npm server-dev to start the server. Server runs on port 3002
• Run npm run test to run the jest and Enzyme tests, CI/CD also enabled

CRUD_API

Endpoints:

/api/about/:id

GET:

Request

GET /api/about/:id

Response

Status: 200
Body:
{
    "course_id": Number,
    "description": String,
    "what_you_will_learn": [
        ArrayOfStrings
    ],
    "skills_you_will_gain": [
        ArrayOfStrings
    ],
    "recent_views": Number,
    "learner_career_outcomes": [
        {
            "icon": String,
            "pct": Number,
            "outcome": String
        },
    ],
    "metadata": [
        {
            "icon": String,
            "title": String,
            "subtitle": String
        },
    ]
}

PUT:

Request

PUT /api/about/:id

Body:
{
    "course_id": Number,
    "description": String,
    "what_you_will_learn": [
        ArrayOfStrings
    ],
    "skills_you_will_gain": [
        ArrayOfStrings
    ],
    "recent_views": Number,
    "learner_career_outcomes": [
        {
            "icon": String,
            "pct": Number,
            "outcome": String
        },
    ],
    "metadata": [
        {
            "icon": String,
            "title": String,
            "subtitle": String
        },
    ]
}

Response

Status: 200
Body: Record Added

POST:

Request

POST /api/about/:id

Body:
{
  "recent_views": Number
}

Response

Status: 200
Body: Record Updated

DELETE:

Request

DELETE /api/about/:id

Response

Status: 200
Body: Record Deleted

API_Performance

Local Testing

• Using K6 I tested a Cassandra DB against a Postgres DB in local development

Database	Requests	Total Requests	Latency (ms)	% Status Code 200
Cassandra	10,000 RPS	600000	3420	87%
Postgres	10,000 RPS	60000	5026	79%
Cassandra	1,000 RPS	600000	52	99%
Postgres	1,000 RPS	60000	139	97%

Deployment

• Deployed 3 cassandra nodes and 3 EC2 Micro instances behind an NGINX load balancer
• Sustained 1,500 RPS to random routes at back 10% of db, tested wtih Loader.io

SSR Deployment and Performance

Google PageSpeed insight score of 99

Screenshot of deployed page