Enterprise-Ready Logging with Serilog in .NET

#dotnet #serilog #logging #aspnetcore

Logging isn't just about printing errors — it's about observability, traceability, and debugging production issues before they become outages. In this post, let’s explore how to implement enterprise-grade logging using Serilog in .NET — from basic setup to advanced features.

Why Serilog?
Serilog is a structured logging library for .NET that makes your logs queryable, filterable, and machine-readable. It supports:

Multiple sinks (console, file, Seq, Elasticsearch, etc.)
Enrichers for contextual data
Asynchronous logging
Easy integration with ASP.NET Core

Getting Started

Install the required NuGet packages:

dotnet add package Serilog.AspNetCore
dotnet add package Serilog.Sinks.Console
dotnet add package Serilog.Sinks.File

In Program.cs (for .NET 6+):

using Serilog;

Log.Logger = new LoggerConfiguration()
    .WriteTo.Console()
    .WriteTo.File("logs/log-.txt", rollingInterval: RollingInterval.Day)
    .Enrich.FromLogContext()
    .CreateLogger();

var builder = WebApplication.CreateBuilder(args);
builder.Host.UseSerilog(); // Replace default logging

var app = builder.Build();

Add Contextual Information

Serilog’s enrichers make your logs more meaningful:

dotnet add package Serilog.Enrichers.Environment
dotnet add package Serilog.Enrichers.Thread

Update configuration:

Log.Logger = new LoggerConfiguration()
    .Enrich.WithEnvironmentUserName()
    .Enrich.WithThreadId()
    .WriteTo.Console()
    .CreateLogger();

This adds thread ID, machine name, and user context to every log.

Logging in Action

Use it anywhere in your app:

public class ProductService
{
    private readonly ILogger<ProductService> _logger;

    public ProductService(ILogger<ProductService> logger)
    {
        _logger = logger;
    }

    public void Process()
    {
        _logger.LogInformation("Processing started at {Time}", DateTime.UtcNow);
    }
}

Use AppSettings (Optional)

You can configure Serilog in appsettings.json for flexibility:

"Serilog": {
  "MinimumLevel": "Information",
  "WriteTo": [
    { "Name": "Console" },
    { "Name": "File", "Args": { "path": "logs/app.txt" } }
  ]
}

And in Program.cs:

builder.Host.UseSerilog((ctx, lc) =>lc.ReadFrom.Configuration(ctx.Configuration));

Sinks You Should Know

Console/File — Local development & basic diagnostics
Seq — Beautiful web UI for structured logs
Elasticsearch — Ideal for large-scale distributed logging
Application Insights — Works well in Azure environment

Best Practices for Production

Use asynchronous sinks to avoid blocking threads.
Avoid logging sensitive info (e.g., passwords, tokens).
Add correlation IDs for request tracing (via middleware).
Log levels properly: Use Debug, Info, Warn, Error, Fatal.
Monitor log size & rotation to prevent disk bloat.

Conclusion

With Serilog, you get powerful, extensible logging out of the box. It gives you structure, performance, and flexibility — everything you need for enterprise-ready applications.

Want to see more on advanced sinks like Elasticsearch + Kibana, or how to build a correlation ID middleware? Drop a comment below!

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Enterprise-Ready Logging with Serilog in .NET

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