What is logging?

A log is a record of events that happen while software runs. The software’s developer adds logging calls to their code to indicate that certain events have occurred. An event is described by a descriptive message which can optionally contain variable data (i.e. data that is potentially different for each occurrence of the event). Events also have an importance which the developer ascribes to the event; the importance can also be called the level or severity.

Why is logging important?

Logging is important for a variety of reasons. For example, logs help you:

• Debug errors: Logs can help you track down bugs and understand why they happen. For example, if your application crashes, you can look at your logs to determine what happened right before the crash.
• Audit activity: Logs can help you understand what actions a user has taken. For example, you can log every time a user makes a request to your application and then use that information to analyze usage patterns or to diagnose errors.
• Monitor performance: Logs can help you monitor your application’s performance. For example, you can log how long it takes your application to process a request and then use that information to identify slow requests or to identify bottlenecks in your application.
• Analyze usage patterns: Logs can help you understand how your application is being used. For example, you can log every time a user makes a request to your application and then use that information to analyze usage patterns or to diagnose errors.
• Identify security issues: Logs can help you identify security issues. For example, you can log every time a user makes a request to your application and then use that information to identify suspicious activity or to identify potential security vulnerabilities.

Different types of logs

1. System Logs: These logs provide information about the system where your application is running. They can include details about system events, system errors, and diagnostic information about various system activities.

2. Error Logs: These logs contain information about errors that occur while your application is running. They can help you identify and debug issues in your application.

3. Access Logs: These logs record all requests processed by the server. They can provide details like who accessed the application, what was accessed, and when it was accessed.

4. Debug Logs: These logs provide detailed information about the application’s execution path, typically used for debugging purposes. They can include variable values, function calls, and other detailed information about how your code is executing.

5. Audit Logs: These logs record the sequence of activities that affect specific operations and procedures. For example, they may track changes to significant data or user and system access logs to critical systems.

Remember, the level of detail and the kind of information you log would depend on your specific use case and the policies around data governance and compliance.