romaleev / nodejs-queue-service

Node.js API queueing service

Node.js API queuing service

There are 3 different APIs the service has to interface with:

1. Shipments API [GET] Accepts a query with 9-digit order numbers and returns a set of products (envelope, box or pallet) equivalent to the last digit.
2. Track API [GET] Accepts a query with 9-digit consignment number and returns one of the following tracking statuses: NEW, IN TRANSIT, COLLECTING, COLLECTED, DELIVERING, DELIVERED.
3. Pricing API [GET] Accepts a query with ISO-2 country code and returns a randomized floating number between 1 and 100.

There are 2 services:

1. Query service [POST]:
   • Exposes a method that accepts a collection of API requests {'API': 'query'}.
   • Makes calls to corresponding APIs.
   • Returns a complete set of responses upon receiving all API responses.
2. Queue query service [POST]:
   • Exposes a method that accepts a collection of API requests {'API': 'query'}.
   • API calls should be throttled and bulked into 1 request per respective API.
   • Makes a queue of calls with threshold of maximum 5 concurrent requests per API endpoint.
   • Returns a complete set of responses upon receiving all corresponding API responses.

Author: Roman Malieiev [e-mail]

Project consists of two builds:

• production optimised
• development with source change watchers

Tech stack:

• Node.js
• Babel for ES6 support with ESLint
• Nodemon development build
• Frisby tests

Installation

1. Install Node.js/npm

2. Navigate to the current folder

3. Run:

   npm install

Running

Run in development mode:

npm start

Build for production:

npm run build

Following urls would be available:

• http://localhost:8080/shipments [GET] - Shipments API
• http://localhost:8080/track [GET] - Track API
• http://localhost:8080/pricing [GET] - Pricing API
• http://localhost:8080/service [POST] - Query service
• http://localhost:8080/service-queue [POST] - Queue query service

NOTE: see tests for requests examples.

Test:

npm start
npm test

Questions

With the above solution, can you imagine a scenario where unnecessary calls to either one of the APIs will happen? If so, how could you solve this?

We can implement caching within some time