Bits of .NET

📝 Console.WriteLine is Not for Production

ILogger is built-in. Structured logging, log levels, multiple providers. No more rolling your own logging.

📝 Basic Logging

public class MyService
{
    private readonly ILogger _logger;
    
    public MyService(ILogger logger)
    {
        _logger = logger;
    }
    
    public void Process(int id)
    {
        _logger.LogInformation("Processing order {OrderId}", id);
        
        try
        {
            // do work
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to process order {OrderId}", id);
            throw;
        }
    }
}

🎯 Log Levels

// Trace: Most detailed (debugging only)
_logger.LogTrace("Entering method");
// Debug: Development debugging
_logger.LogDebug("Variable value: {Value}", value);
// Information: Normal application flow
_logger.LogInformation("User {UserId} logged in", userId);
// Warning: Unexpected but not fatal
_logger.LogWarning("API response slow: {Duration}ms", duration);
// Error: Exception or failure
_logger.LogError(ex, "Database connection failed");
// Critical: Application crash
_logger.LogCritical("Application shutting down unexpectedly");

💡 Providers

• Console (default)
• Debug (Output window)
• EventLog (Windows)
• Application Insights (Azure)
• Seq, Elasticsearch, Splunk (via Serilog)