For Sourced Group Interview Technical Challenge

colour-to-rgb-decimal

REST API that when given colour in string format, return RGB decimal value.

>> GET /colours/red
<< {colour: 'red', rgb: '(255,0,0)'}

>> GET /colours/green
<< {colour: 'green', rgb: '(0,255,0)'}

>> GET /colours/blue
<< {colour: 'blue', rgb: '(0,0,255)'}

Click to expand!

Assumed Requirements
- Functional Requirements
- Non-functional requirements
  - 1. Must be able to support 1000 concurrent requests
  - 2. Response time must be < 1s
API Endpoint Usage
Tech Stack
Architecture Diagram
Running Locally
Deployment
Future Improvement

Assumed Requirements

Functional Requirements

1. API will support the following colour as version 1

Colour	Decimal Code
black	(0,0,0)
white	(255,255,255)
red	(255,0,0)
lime	(0,255,0)
blue	(0,0,255)
yellow	(255,255,0)
cyan / aqua	(0,255,255)
magenta / fuchsia	(255,0,255)
silver	(192,192,192)
gray	(128,128,128)
maroon	(128,0,0)
olive	(128,128,0)
green	(0,128,0)
purple	(128,0,128)
teal	(0,128,128)
navy	(0,0,128)

2. Colour string will always be in lowercase

When there is a need for a space in colour string, it will be denoted by -. For example: dark-red

3. Clients will be able to get all colour string to RGB mapping

Response will be a list containing objects of existing colour to RGB mapping

[
  {
    "colour": "orange",
    "rgb": "(255,165,0)"
  },
  {
    "colour": "red",
    "rgb": "(255,0,0)"
  },
  ...
]

4. Clients will be able to get individual colour string to RGB mapping

Response will be an object which represent a colour to RGB mapping

{
  "colour": "red",
  "rgb": "(255,0,0)"
}

5. Authorized users will be allowed to add new colour string to RGB mapping

if colour string does not exists, do an upsert
if colour string exists but the decimal colour are different, do an upsert
if colour string exists and decimal colour are the same do nothing
added colour will always will be in the following format, no input verification is required

{
  "colour": "{colour_name_in_string}",
  "rgb": "{rgb_decimal_code}"
}

// e.g
{
  "colour": "green",
  "rgb": "(0,255,0)"
}

6. Authorized users will be allowed to delete existing colour string to RGB mapping

Non-functional requirements

1. Must be able to support 1000 concurrent requests

2. Response time must be < 1s

API Endpoint Usage

No.	Method	URI	Request Body	Requires Bearer Token
1	PUT	`/colours`	`{colour: 'orange', rgb: '(255,165,0)'}`	✅
2	GET	`/colours`	-	❌
3	GET	`/colours/{colour-in-string}`	-	❌
4	DELETE	`/colours/{colour-in-string}`	-	✅

1. Add/Update colour to RGB decimal

https://dzkakt1r2b.execute-api.ap-southeast-1.amazonaws.com/api/colours

Bearer Token -> 'allow' (without quotes ')

>> PUT /colours authorization: Bearer allow {colour: 'orange', rgb: '(255,165,0)'}
<< {colour: 'orange', rgb: '(255,165,0)'}

2. Get all colour to RGB decimal

https://dzkakt1r2b.execute-api.ap-southeast-1.amazonaws.com/api/colours

>> GET /colours
<< [ {colour: 'red', rgb: '(255,0,0)'}, {colour: 'green', rgb: '(0,255,0)'}, ... ]

3. Get RGB decimal from colour

https://dzkakt1r2b.execute-api.ap-southeast-1.amazonaws.com/api/colours/blue

>> GET /colours/blue
<< {colour: 'blue', rgb: '(0,0,255)'}

4. Delete colour to RGB decimal mapping

https://dzkakt1r2b.execute-api.ap-southeast-1.amazonaws.com/api/colours/blue

Bearer Token -> 'allow' (without quotes ')

>> DELETE /colours/blue authorization: Bearer allow
<< {"message": "Successfully deleted blue"}

Tech Stack

AWS Chalice -- Python Serverless Microframework for AWS
- To Build CRUD REST API with API Gateway + Lambda
AWS Cloudformation -- Provision infrastructure as code
- Deploying dynamoDB using cloudformation template

Architecture Diagram

Running locally

Requirements:

Python 3.7 and above
AWS credentials configured in ~/.aws/credentials

pip install chalice
cd app
chalice local

Deployment

cd app
chalice deploy

Future Improvement

1. Caching

Currently, there is no caching of result. Whenever data related operation is carried out, dynamoDB table is scanned/queried.

This could lead to high charges for dynamoDB and increased latency for client.

Could add a caching layer in the system. Either before hitting the dynamoDB or at API Gateway itself.

2. Monitoring / Logging / Analytics

Only basic cloudwatch logs for now.

Could add workers to process the usage pattern of the API.

3. Deployment Pipeline

Could setup a deployment pipeline to automatically push changeset to production

OkkarMin/colour-to-rgb-decimal