Cookbooks
C#
Chapter 5. Good Coding Practices
Logging

C#:
Logging

How to:

In C#, you can use the built-in System.Diagnostics namespace or third-party libraries like NLog or log4net. Here’s a quick example using the ILogger interface available in .NET Core:

using Microsoft.Extensions.Logging;
using System;

public class Program
{
    public static void Main()
    {
        using var loggerFactory = LoggerFactory.Create(builder => {
            builder.AddConsole();
        });

        ILogger logger = loggerFactory.CreateLogger<Program>();

        logger.LogInformation("This is an informational message.");
        logger.LogWarning("This is a warning message.");
        logger.LogError("This is an error message.");
    }
}

Sample output:

info: Program[0]
      This is an informational message.
warn: Program[0]
      This is a warning message.
fail: Program[0]
      This is an error message.

Deep Dive

The history of logging in software development is nearly as old as programming itself; it’s evolved from simple print statements to sophisticated, configurable systems. Originally, logging was done by writing to files or the console, but this has grown to include more complex structures like log aggregation systems and distributed tracing platforms (like ELK stack or Jaeger).

Alternatives to the built-in logging in .NET include third-party libraries:

  • NLog: versatile and easy to set up, with lots of features for routing, formatting, and filtering logs.
  • log4net: inspired by the Java log4j library, it’s highly configurable from XML and supports a variety of log repositories.

When it comes to implementation details, the choice of your logging abstraction (like Microsoft.Extensions.Logging) and the underlying logging provider can significantly affect your application’s performance and reliability. It’s crucial to configure logging levels appropriately and ensure that writing logs doesn’t become a bottleneck.

Also, structured logging - where you log not just strings but key-value pairs or objects - allows for more precise and actionable logs, which are easier to query and analyze.

See Also

Handling errorsOrganizing code into functions