What are the main principles of service design to minimize data or resource loss?

The main principles of service design to minimize data and resource loss include:

• Idempotency of operations: repeating the same operation should not lead to errors or duplicate data.
• Transactional and atomic operations: data-changing operations should be atomic to avoid partial updates.
• Failure handling and retries: the service should be able to retry operations in case of temporary errors.
• Logging and monitoring: for quick detection and response to issues.
• Use of queues and buffers: to smooth out load peaks and prevent message loss.
• Backup and recovery: regular creation of data backups.
• Resource limits and timeouts: to prevent hangs and resource leaks.

Example of an idempotent operation in Java:

public void processOrder(String orderId) {
    if (orderAlreadyProcessed(orderId)) {
        return; // prevent reprocessing
    }
    // process order
}