Payment Initiation and Amount Transfer Application Using Apache Kafka and Spring Boot

This application facilitates payment initiation and amount transfers between two accounts.

Prerequisites

Before running the application, ensure the following are set up:

1. Kafka Setup
   Set up Kafka on your local system. Follow the instructions in the official Kafka documentation: Kafka Quickstart.

2. PostgreSQL Configuration
   Enter your PostgreSQL database credentials in the application.yml file.

Running the Application

1. After configuring Kafka and PostgreSQL, run the application.
2. Once the application is up and stable, insert initial balances into the accounts table.

Insert Initial Account Balances

Execute the following SQL queries to add balances to the accounts:

INSERT INTO accounts (account_id, balance) VALUES ('1101', 25000.0);
INSERT INTO accounts (account_id, balance) VALUES ('1102', 20000.0);
INSERT INTO accounts (account_id, balance) VALUES ('1103', 30000.0);

Initiating a Transaction

Use the following cURL command to initiate a transaction:

curl --location 'http://localhost:8080/transactions/initiate' \
--header 'Content-Type: application/json' \
--data '{
  "transaction_id": "34fb4335-fb89-4e33-91fc-c9d37adfcb75",
  "amount": 800,
  "currency": "INR",
  "sender_id": "1103",
  "receiver_id": "1102",
  "transaction_type": "payment"
}'

Transaction Flow

1. Upon executing the cURL command, the transaction initiation is logged and stored in the Kafka cluster.
2. A Kafka consumer validates the transaction data.
3. If the sender has sufficient balance, the transaction details are saved to the database.

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