Error Handling

Patterns for building resilient Python systems. Focus on recoverability, not just catching exceptions.

Core Principle

Handle what you can recover from. Propagate what you can't. Never swallow errors silently.

Exception Hierarchy

Design exceptions that help the caller decide what to do.

class AppError(Exception):
    """Base for all application errors. Always catchable as a group."""

class ConfigError(AppError):
    """Configuration is invalid or missing. Not retryable."""