Drools Rule Engine Project

This project demonstrates the implementation of a rule engine using Drools with Spring Boot for processing card-based discounts.

Getting Started

Prerequisites

• Java 17 or later
• Maven 3.6.x or later
• Your favorite IDE (IntelliJ IDEA, Eclipse, or VS Code)

Project Structure

src/
├── main/
│ ├── java/
│ │ └── com/ruleengine/droolengine/
│ │ ├── config/
│ │ │ └── DroolConfig.java
│ │ ├── controller/
│ │ │ └── OfferController.java
│ │ ├── model/
│ │ │ └── Order.java
│ │ └── DroolengineApplication.java
│ └── resources/
│ └── KieRule/
│ └── offer.drl

Docker Support

Prerequisites

• Docker installed on your machine
• Docker Compose (included with Docker Desktop)

Docker Files

The project includes the following Docker-related files:

• Dockerfile: Contains instructions for building the Docker image
• docker-compose.yml: Defines the service configuration

Building and Running with Docker

1. Build the Docker image:

docker build -t drools-rule-engine .

2. Run using Docker:

docker run -p 8080:8080 drools-rule-engine

3. Or using Docker Compose:

docker-compose up -d

Configuration

Maven Dependencies

The project requires the following key dependencies:

• spring-boot-starter-web
• drools-core
• drools-compiler
• drools-decisiontables
• drools-mvel

Business Rules

The current implementation includes rules for the following card types:

• HDFC: 10% discount for orders above ₹10,000
• ICICI: 8% discount for orders above ₹15,000
• SBI: 15% discount for orders above ₹15,000

API Endpoints

Process Order Discount

POST /order
Content-Type: application/json

{
    "cardType": "HDFC",
    "price": 20000
}

Running the Application

1. Clone the repository

git clone https://github.com/deepak04112002/pixel_generator.git

2. Navigate to the project directory

cd droolengine

3. Run the application:

mvn spring-boot:run

The application will start on port 8080

Testing

To test the rules, send a POST request to http://localhost:8080/order with the appropriate request body.

Example using curl:

curl -X POST \
  http://localhost:8080/order \
  -H 'Content-Type: application/json' \
  -d '{
    "cardType": "HDFC",
    "price": 20000
}'

Adding New Rules

To add new rules:

1. Open src/main/resources/KieRule/offer.drl

2. Add your rule following the format:

rule "RuleName"
when
    orderObject: Order(cardType == "NEW_CARD", price > amount)
then
    orderObject.setDiscount(discountPercentage);
end

Troubleshooting

Common issues and solutions:

1. Rule not firing:

• Verify rule syntax in offer.drl file.
• Check if the rule conditions match your input.
• Ensure proper package declaration in DRL file.

2. Application fails to start:

• Verify proper placement of offer.drl file
• Check for proper dependency versions.
• Ensure Java version compatibility.