Soenneker.ApplicationInsights.Processor.SignalR 4.0.403

Soenneker.ApplicationInsights.Processor.SignalR

An OpenTelemetry ASP.NET Core instrumentation filter that excludes requests under /hubs from exported request traces.

Use it when SignalR connection, transport, and negotiate requests create unwanted Application Insights volume and every application hub is mapped beneath /hubs.

Installation

dotnet add package Soenneker.ApplicationInsights.Processor.SignalR

Registration

using Azure.Monitor.OpenTelemetry.AspNetCore;
using Soenneker.ApplicationInsights.Processor.SignalR.Registrars;

builder.Services
       .AddOpenTelemetry()
       .UseAzureMonitor();

builder.Services.AddSignalRHubTelemetryProcessor();

The registrar adds SignalRTelemetryProcessor as an IConfigureOptions<AspNetCoreTraceInstrumentationOptions> implementation. It does not register a separately resolved processor service.

What is filtered

The filter performs a case-insensitive PathString.StartsWithSegments("/hubs") check.

Filtered examples:

/hubs
/hubs/chat
/hubs/chat/negotiate
/HUBS/notifications

Requests outside that path segment continue through ASP.NET Core instrumentation:

/api/hubs
/hub
/health

The filter prevents collection of the matching ASP.NET Core server activities. It does not merely hide them in the Azure portal, and it does not filter application logs or custom telemetry emitted separately.

Map hubs consistently

The package assumes hubs are rooted at /hubs:

app.MapHub<ChatHub>("/hubs/chat");
app.MapHub<NotificationsHub>("/hubs/notifications");

A hub mapped elsewhere is not filtered. Conversely, every non-SignalR endpoint under /hubs is also filtered.

Composition caveat

SignalRTelemetryProcessor assigns AspNetCoreTraceInstrumentationOptions.Filter. It does not combine its predicate with a filter already configured by the application or another package. Whichever options configurator assigns the property last determines the effective filter.

When the application needs several conditions, prefer one application-owned predicate that composes them explicitly:

builder.Services.Configure<AspNetCoreTraceInstrumentationOptions>(options =>
{
    options.Filter = context =>
        !context.Request.Path.StartsWithSegments("/hubs") &&
        !context.Request.Path.StartsWithSegments("/health");
});

Do not register the package's configurator in addition to a composed application filter unless the resulting options order is intentional.

API

AddSignalRHubTelemetryProcessor(IServiceCollection) registers the ASP.NET Core trace-options configurator and returns the same service collection for chaining.