Fusing Web Stacks With COBOL Microservices

• Download source - 112 KB

Introduction

According to a 2015 report by Reuters¹:

• 43% of banking systems are built on COBOL
• 80% of in-person transactions use COBOL
• 95% of ATM swipes rely on COBOL code
• 220 billion lines of COBOL are in use today

This application is a case study on Dockerizing a COBOL application for computing income taxes, and integrating it into a Dockerized web stack.

Prerequisites

Docker and docker-compose are needed to run the application. Installation instructions can be found at Install Docker and Install Docker Compose.

How It Works

This project is divided into several parts:

• Web Tier
  • A React front end styled with Bootstrap running on Node
• API Tier
  • A RESTful API built with Python and Flask
  • A COBOL shared library for computing income taxes compiled with GnuCOBOL
  • Responsible for retrieving taxpayer information from PostgreSQL and natively passing that information into a COBOL subroutine to compute income taxes owed
• Data Tier
  • A PostgreSQL database containing taxpayer information
• Reverse Proxy
  • Using Træfik as a reverse proxy and load balancer
• Docker Compose
  • For orchestrating containers and pre-populating the database server

Running the App

Start the application with the following command:

sudo docker-compose up -d 

To view the front end navigate to:

http://web.docker.localhost 

The database is pre-populated with taxpayer IDs in the range of 1 - 1000. Enter a taxpayer ID and click Submit.

History

• 30^th April, 2018: Initial release