Payment Processor Mockup

Purpose

This service is meant to demo a payment processor service. It accepts card transaction requests and returns either an APP (approval), DEC (decline), or ERR (error). It is configured to give back an APP 70% of the time, a DEC 20% of the time, and an ERR 10% of the time.

It is meant to be run in conjunction with the Payment Gateway mockup service in this same repo.

Since this app is stateless, multiple instances of it can be run with a load balancer in front of it.

Installation

Prerequisites

• Java SDK version 17 installed, on the server where this code is to be run (the project was written with Java 17 in mind, although it will probably work fine with versions higher than 17)
  
  You can check your java version by running java -version
  
  
• Maven, on the server where you have the code
  
  You can verify Maven is installed by running mvn -version
  
  

To install and run this code, you need to do the following

1. Pull the code locally from the github repository.
   
   

2. Set the JAVA_HOME environment variable pointing to your Java 17 SDK; for example

   export JAVA_HOME=/Library/Java/JavaVirtualMachines/jdk-17.jdk/Contents/Home
   

3. Run mvn package from the project directory to package this executable as a JAR file
   
   After this command finishes, you should see a jar file in the target directory:

   $ ls target/*.jar
   target/PaymentProcessorMockup-0.0.1-SNAPSHOT.jar
   

4. Configure the settings, most notably the port where this service will run. The settings are configured in the code in the application.properties file. You can override the properties that were packaged up with the JAR file by specifying the location of an external properties file:

   java -jar <jar file> --spring.config.location=processor.properties
   

   The file should look like this (see: src/main/resources/application.properties):

   server.port=8082
   
   payments_demo.processor.sleepMs=10
   

5. Run the service by executing a command like the following. It is a good idea to specify the max heap memory for this process. In the example below, we're specifying a max heap size of 2GB with -Xmx2g.

   java -Xmx2g -jar target/PaymentProcessorMockup-0.0.1-SNAPSHOT.jar --spring.config.location=processor.properties