Logging Fundamentals

All Duende Software products (IdentityServer, Backend for Frontend (BFF), Access Token Management, etc.) use the standard logging facilities provided by ASP.NET Core (Microsoft.Extensions.Logging). This means they integrate seamlessly with whatever logging provider you choose for your application.

This guide provides general instructions for setting up logging that apply to all our products.

Log Levels

We adhere to the standard Microsoft guidelines for log levels. Understanding these levels helps you configure the appropriate verbosity for your environment.

• Trace
  • Usage: Extremely detailed information for troubleshooting complex issues.
  • Production: Do not enable in production unless specifically instructed for diagnostics. May contain sensitive data (e.g., token hashes, PII).
• Debug
  • Usage: Internal flow details, useful for understanding why a decision was made (e.g., policy evaluation, token validation steps).
  • Production: Generally disabled in production, but safe to enable temporarily for deeper investigation.
• Information
  • Usage: High-level events tracking the general flow (e.g., “Request started”, “Token issued”).
  • Production: Often the default level for production.
• Warning
  • Usage: Unexpected events that didn’t stop the application but might require investigation (e.g., “Invalid client configuration detected”).
• Error
  • Usage: Exceptions and errors that cannot be handled gracefully.
• Critical
  • Usage: Failures that require immediate attention (e.g., “Signing key not found”).

Setup for Microsoft.Extensions.Logging

This is the default logging provider for ASP.NET Core. If you haven’t configured a third-party logger, this is what you are using.

You can configure log levels in your appsettings.json file. To get detailed logs from Duende products, you often want to set the Duende namespace (or specific sub-namespaces) to Debug.

appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information",
      // Enable Debug logs for all Duende products
      "Duende": "Debug"
    }
  }
}

Setup for Serilog

Serilog is a popular structured logging library for .NET. We highly recommend it for its flexibility and rich sink ecosystem (Console, File, Seq, Elasticsearch, etc.).

1. Installation

Install the necessary packages:

dotnet add package Serilog.AspNetCore

2. Configuration In Program.cs

Configure Serilog early in your application startup to capture all logs, including startup errors.

Program.cs

using Serilog;

var builder = WebApplication.CreateBuilder(args);

// Configure Serilog
builder.Host.UseSerilog((ctx, lc) => lc
    .WriteTo.Console(outputTemplate: "[{Timestamp:HH:mm:ss} {Level}] {SourceContext}{NewLine}{Message:lj}{NewLine}{Exception}{NewLine}")
    .Enrich.FromLogContext()
    .ReadFrom.Configuration(ctx.Configuration));

var app = builder.Build();

app.UseSerilogRequestLogging(); // Optional: cleaner HTTP request logging

// ... rest of your pipeline

3. Configuration In appsettings.json

You can then control log levels via appsettings.json. This approach allows you to change log levels without recompiling your code.

{
  "Serilog": {
    "MinimumLevel": {
      "Default": "Information",
      "Override": {
        "Microsoft": "Warning",
        "Microsoft.Hosting.Lifetime": "Information",
        "System": "Warning",
        // Enable detailed logging for Duende products
        "Duende": "Debug"
      }
    }
  }
}

Troubleshooting Specific Products

If you are debugging a specific component, you can target its namespace to reduce noise.

Product	Namespace
IdentityServer	Duende.IdentityServer
BFF	Duende.Bff
Access Token Management	Duende.AccessTokenManagement

Example appsettings.json for debugging only BFF interactions:

"Duende.Bff": "Debug",
"Duende.IdentityServer": "Information"