Introduction to Logging¶
The Basics¶
- Logging consists of two simple elements: log events and log targets. For example, a family’s signature on a guest role at a wedding, or a security guard’s notes in his notebook.
- In software, logging is primarily used for troubleshooting/debugging and auditing purposes.
- A logging framework is responsible for providing a structured way to get log events into log targets.
Log Events¶
- Log events are messages or objects to be delivered to a log target (the family’s signature or the security guard’s note)
- Log events contain information about an event that happened
- A log event can be a simple message like “Hello, World!”, or a complex multilevel object that represents a web request
Log Targets¶
- Log targets receive or store log events
- A log target can display a log event immediately, such as in a terminal window, or store the log event to persistent storage, such as in a file or database
- Log targets can also interface web services or email clients, delivering the log event to an external destination
- A single log target is generally responsible for a single destination. For example, a single “Text File Target” would write to a single file
- A single application will likely have multiple targets