Start Debugging

logging

10 posts

2026-10-26 dotnet csharp logging

How to use a different Serilog output template per log level from appsettings.json

outputTemplate is fixed per sink, so per-level formatting needs either an ExpressionTemplate with {#if @l ...} blocks or two Logger sub-loggers with ByIncludingOnly / ByExcluding filters. Both configured purely from appsettings.json, tested on Serilog 4.4, Serilog.Settings.Configuration 10.0.1 and Serilog.Expressions 5.0.

2026-10-16 dotnet logging observability

.NET Extensions 10.11: buffered logs can finally keep their scopes

Microsoft.Extensions.Telemetry 10.11.0, released October 15, 2026, adds an experimental IncludeScopes option to global and per-request log buffering, so OrderId and TenantId from BeginScope survive a Flush() instead of being silently dropped.

2026-10-11 csharp dotnet file-io

How to tail a log file in C# while another process is still writing to it

Open the log with FileShare.ReadWrite | FileShare.Delete, seek to the end, poll for new bytes, decode them with your own UTF-8 Decoder instead of StreamReader, and handle truncation and rotation explicitly. A tested tail -F implementation for .NET 10 and .NET 11.

2026-09-21 aspnetcore dotnet-10 logging

How to add the current user id to every log entry in ASP.NET Core

A BeginScope middleware misses the exception handler's error log and the Request finished line. Register an ILogEnricher that reads the user from IHttpContextAccessor, open a scope only when work leaves the request, and watch out for Serilog's AddSerilog silently cancelling enrichment.

2026-08-18 errors dotnet logging

Fix: CA1873 "Evaluation of this argument may be expensive and unnecessary if logging is disabled"

CA1873 fires on the implicit params object[] allocation, so almost every LogDebug call trips it. Fix it with [LoggerMessage] or an IsEnabled guard.

2026-08-17 dotnet logging security

How to redact sensitive values from logs with LogProperties and data redaction in .NET

A complete guide to redacting classified data in source-generated logs: build a taxonomy, write a Redactor, wire EnableRedaction and AddRedaction, and understand the discriminator that silently breaks partial masking. With real output from Microsoft.Extensions.Compliance.Redaction 10.9.0.

2026-07-25 migration dotnet dotnet-11

Migrate from ILogger string interpolation to structured logging message templates in .NET 11

A step-by-step guide to converting $-interpolated ILogger calls into message templates and [LoggerMessage] source-generated methods on .NET 11: what breaks, how to sweep a codebase with CA2254, how to verify the JSON state, and how to roll back.

2026-07-19 ef-core dotnet csharp

How to log the SQL that EF Core 11 generates

See the exact SQL Entity Framework Core 11 sends to your database, with parameter values, using LogTo, Microsoft.Extensions.Logging, and ToQueryString.

2026-06-05 migration serilog opentelemetry

Migrate from Serilog to OpenTelemetry logging in .NET 11

A step-by-step guide to moving a .NET 11 app off Serilog and onto OpenTelemetry logging: the low-risk Serilog.Sinks.OpenTelemetry bridge, the full Microsoft.Extensions.Logging cut-over, what breaks, how to verify, and how to roll back.

2026-05-01 csharp dotnet dotnet-11

How to set up structured logging with Serilog and Seq in .NET 11

A complete guide to wiring Serilog 4.x and Seq 2025.2 into a .NET 11 ASP.NET Core app: AddSerilog vs UseSerilog, two-stage bootstrap logging, JSON configuration, enrichers, request logging, OpenTelemetry trace correlation, API keys, and the production gotchas around buffering, retention, and signal level.