NeonLog.CSharp.AspNetCore 0.1.0-ci.78

NeonLog.CSharp.AspNetCore

ASP.NET Core request logging middleware for neonlog-c. Writes a structured completion log event for every HTTP request, with dynamic level selection and automatic population of NeonLogHttpRequestContext for downstream enrichers.

Quick start

using NeonLog.AspNetCore;

var builder = WebApplication.CreateBuilder(args);

// Register NeonLog as the logging provider
builder.Logging.AddNeonLog(builder.Configuration.GetSection("NeonLog"));

var app = builder.Build();

// Add request logging middleware (early in the pipeline)
app.UseNeonLogRequestLogging();

app.MapControllers();
app.Run();

Each request produces a log event like:

INF  HTTP GET /api/orders responded 200 in 42ms

Configuration

NeonLogRequestLoggingOptions

Default GetLevel behaviour

When no delegate is provided, the middleware uses the same logic as the Serilog UseSerilogRequestLogging example:

Override with a custom delegate:

app.UseNeonLogRequestLogging(options =>
{
    options.GetLevel = (httpContext, elapsedMs, ex) =>
    {
        if (ex != null) return NeonLogLevel.Error;
        if (httpContext.Response.StatusCode > 499) return NeonLogLevel.Error;

        var path = httpContext.Request?.Path.Value?.ToLowerInvariant();
        if (path == "/" || (path?.StartsWith("/health") ?? false))
            return NeonLogLevel.Verbose;

        return httpContext.Request.Method == "GET"
            ? NeonLogLevel.Debug
            : NeonLogLevel.Information;
    };
});

Adding custom properties via EnrichDiagnosticContext

Use the EnrichDiagnosticContext callback to attach properties from HttpContext that aren't captured automatically:

app.UseNeonLogRequestLogging(options =>
{
    options.EnrichDiagnosticContext = (props, ctx) =>
    {
        props["CustomHeader"] = ctx.Request.Headers["X-Custom"].ToString();
    };
});

Properties added here are attached to the request completion log event via BeginScope, so they appear alongside the template parameters.

Custom message template

app.UseNeonLogRequestLogging(options =>
{
    options.MessageTemplate =
        "[{RequestMethod}] {RequestPath} -> {StatusCode} ({ElapsedMilliseconds}ms)";
});

How it works

1. On request arrival, the middleware populates NeonLogHttpRequestContext with data extracted from HttpContext (method, path, user-agent, client IP, etc.).
2. It calls _next(context) and measures elapsed time with Stopwatch.
3. After the response, it updates the ambient context with the status code and elapsed time.
4. The GetLevel delegate determines the log level.
5. A structured log event is written via ILogger<RequestLoggingMiddleware>.

Properties populated by the middleware

The middleware sets every field on NeonLogHttpRequestData from HttpContext:

Integration with the HttpRequest enricher

Because the middleware sets NeonLogHttpRequestContext, any downstream code that logs within the same request automatically gets HTTP request properties attached — provided the HttpRequest enricher is configured:

// In NeonLog options:
options.Enrichers.Add(NeonLogBuiltInEnricher.HttpRequest);

Each log event within the request context will receive the following properties (both neonlog-c native names and HSSerilog-compatible aliases are emitted):

Note: HttpRequestBody is only populated if you add middleware that reads the request body and sets RequestBody on the ambient context.

API

IApplicationBuilder.UseNeonLogRequestLogging()

Registers RequestLoggingMiddleware with default options. Place early in the pipeline (after exception handling, before routing) so it captures the full request/response cycle.

IApplicationBuilder.UseNeonLogRequestLogging(Action<NeonLogRequestLoggingOptions>)

Registers the middleware with a configuration delegate for custom level selection, enrichment, or message template.

Migrating from Serilog (HSSerilog)

If you are migrating from HSSerilog's RequestEnricher, the property names are fully compatible. The following HSSerilog property names are emitted as aliases alongside the native neonlog-c names:

No changes to your log queries or dashboards are needed.

NuGet

dotnet pack bindings/dotnet/NeonLog.CSharp.AspNetCore/NeonLog.CSharp.AspNetCore.csproj -c Release

Package version follows $(NeonLogPackageVersion) (default 0.1.0). The package has no native assets — it depends solely on the NeonLog.CSharp package for the native neonlog-c runtime.