Please find source code in userprocessing/src/main/java/com/example

Database

• The database contains a single table, USER, which stores information about users (e.g., name, email).
• Each record includes a processed field (boolean) to indicate whether the record has been processed.

REST API

• The application exposes a REST endpoint /users to accept user information in JSON format and store it in the database.
• The endpoint accepts POST requests with the user details and inserts new records into the USER table.

Database Polling

• A scheduled task polls the USER table periodically (every 5 seconds) to find unprocessed users.
• Once unprocessed records are found, they are processed (printing user details to the console) and marked as processed.

Processing Records

• To ensure that each record is processed exactly once, even in a cloud environment with multiple pods, the application must avoid duplicate processing due to concurrency issues.
• I have opted for the PESSIMISTIC_WRITE locking mechanism instead of using a @Version field with optimistic locking.
  • This approach prevents concurrency issues by locking the record for processing, ensuring that no other pods can access it until the processing is complete.

To Build & Run

• Build the project:

  • Run the following command to clean and install dependencies:
    • mvn clean install

• Run the application:

  • Once built, execute the following command to start the application:
    • mvn spring-boot:run