Can you tell about the principles and types of logging in systems?

Logging is the process of recording information about the system's operation for subsequent analysis and debugging.

Logging principles:

• Log levels: usually use levels DEBUG, INFO, WARN, ERROR, FATAL to filter messages by importance.
• Structured: logs should be structured to facilitate easy parsing and analysis.
• Context: it is useful to include context in logs (e.g., request identifiers) to link events.
• Performance: logging should not significantly impact system performance.

Types of logging:

• System logging: recording OS and service events.
• Application logging: logs of application operation, errors, business events.
• Audit: recording user actions for security and compliance.
• Tracing: detailed logging for debugging and performance analysis.

Example of a log entry in Python:

import logging
logging.basicConfig(level=logging.INFO)
logging.info('Request processing started')