[FEAT] Implement Background Email Sending with Celery and RabbitMQ

[PcNerd9]

Description

Develop a background task system to process email requests stored in the database queue. Use Celery with RabbitMQ to handle the email sending asynchronously. This system should fetch email requests from the queue and send them without blocking the main application flow.

Acceptance Criteria

• Use Celery to process email requests from the database queue.
• Use RabbitMQ as the message broker for Celery.
• Ensure that email sending tasks are processed asynchronously in the background.
• Implement retry mechanisms for failed email sending attempts.
• Handle unexpected errors and log them appropriately.

Data Validation

• Input Validation: Validate that the email request data retrieved from the queue is correctly formatted.
• Output Validation: Ensure that the email sending process correctly handles the email data and logs success or failure.

Authentication and Authorization

• Authentication: Ensure the task workers authenticate with the necessary systems to send emails.
• Authorization: Verify that the task workers have permission to process email requests.

Error Handling

• Error Responses: Log errors for scenarios such as failed email sending, invalid email data, and queue retrieval issues.
• Edge Cases: Consider edge cases such as queue connection failures, email server issues, and malformed email requests.

Performance and Security

• Performance Considerations: Optimize the Celery worker processes for efficient handling of large volumes of email requests.
• Security Concerns: Secure the connection between Celery and RabbitMQ, and ensure sensitive email data is handled securely.

Documentation

• API Documentation: Provide documentation on how the Celery and RabbitMQ integration works.
• Technical Notes: Include notes on setting up and configuring Celery and RabbitMQ, and any limitations.

Testing Requirements

• Unit Tests: Implement unit tests for the Celery tasks, including email retrieval and sending logic.
• Integration Tests: Create integration tests to ensure the entire background email sending system works as expected.

Dependencies and Impact

• Dependencies: Identify dependencies on the database queue, RabbitMQ, and any existing email infrastructure.
• Impact Analysis: Assess the potential impact on the main application flow and ensure compatibility with other features.

Requirements

• Set up Celery and RabbitMQ.
• Implement a worker to fetch and process email requests from the database queue.
• Ensure emails are sent asynchronously.
• Implement retry logic for failed email requests.
• Handle and log errors.

Expected Outcome

• Email requests stored in the database queue are processed in the background.
• Emails are sent without blocking the main application flow.
• Any errors are properly logged and retried if necessary.

Testing

• Celery Worker Functionality

  • Ensure that Celery workers are correctly fetching email requests from the database queue.
  • Verify that the email requests are processed and sent as expected.
  • Confirm that retries occur if an email sending attempt fails.

• Email Sending

  • Send test email requests to verify that emails are sent correctly.
  • Check that emails are dispatched asynchronously without blocking the main application.

• Error Handling

  • Simulate errors during the email sending process to ensure they are logged and retried if necessary.
  • Verify that errors are handled and logged appropriately.

• System Integration

  • Ensure that Celery and RabbitMQ are correctly integrated with the main application.
  • Verify that the entire system works together as expected, including task queuing, processing, and email sending.