Telemetrix 0.1.0

Telemetrix

In-process OpenTelemetry trace, log and metric visualizer with an embedded executive dashboard.

Telemetrix is a zero-dependency, local alternative to Jaeger, Zipkin and the Aspire dashboard for ASP.NET Core development. It captures OpenTelemetry traces, logs and metrics inside your running application and renders them in an embedded dashboard — no Docker, no external collector, no orchestration.

builder.AddTelemetrix();          // capture traces, logs, metrics + EF Core SQL
app.UseTelemetrixDashboard();     // dashboard at /telemetrix

Open https://localhost:<port>/telemetrix and the waterfalls, SQL and metrics are right there.

Why

.NET 8, 9 and 10 lean heavily on native Activity, DiagnosticSource and OpenTelemetry, so distributed tracing is everywhere. But seeing that telemetry locally usually means spinning up Docker containers for Jaeger/Zipkin/Aspire, or squinting at log files.

Telemetrix removes that friction. It is a plain NuGet package: an in-process exporter that funnels spans, logs and metrics straight into an embedded dashboard served by your own app.

Features

• Instant waterfall graphs — trace trees that match request lifetimes across HTTP calls, internal layers and database round-trips.
• SQL parameter inspector — Entity Framework Core commands are captured automatically with their bound parameter values, cleanly formatted SQL, row counts and the exact application line of code that issued the query.
• Logs, correlated — every log entry is linked to its trace and span.
• Metrics — counters, gauges and histograms charted with uPlot.
• Executive dashboard — a refined light/dark UI with an overview, traces, logs and metrics tabs.
• Zero dependency setup — one call wires a complete OpenTelemetry pipeline; the dashboard is a single self-contained middleware. Nothing to deploy alongside your app.
• Development-only — Telemetrix is dormant outside the Development environment: no exporters, no capture, no dashboard, no measurable overhead.

Requirements

• .NET 10 SDK (developed against 10.0.300)
• An ASP.NET Core app using the minimal hosting model (WebApplication.CreateBuilder)

dotnet pack src/Telemetrix/Telemetrix.csproj -c Release

Then add a package or project reference to Telemetrix.

Quick start

using Telemetrix;

var builder = WebApplication.CreateBuilder(args);

// 1. Register Telemetrix. This wires a full OpenTelemetry pipeline
//    (ASP.NET Core + HttpClient instrumentation, traces, metrics, logs)
//    and the Entity Framework Core SQL inspector.
builder.AddTelemetrix();

var app = builder.Build();

// 2. Mount the dashboard. Place it early in the pipeline.
app.UseTelemetrixDashboard();

app.MapGet("/", () => "Hello world");
app.Run();

Browse to /telemetrix.

The dashboard

Open any trace to see the waterfall. Click a span to expand its attributes, events, correlated logs — and, for database spans, the SQL parameter inspector:

• the formatted SQL statement,
• a table of every bound parameter (name, value, type, direction),
• the file and line of application code that issued the command,
• duration and rows affected.

The dashboard supports light and dark themes and a live (auto-refresh) mode.

How it works

AddTelemetrix() registers:

• a singleton TelemetrixStore — bounded, in-memory ring buffers for traces, logs and metrics;
• custom OpenTelemetry exporters (BaseExporter<Activity>, BaseExporter<LogRecord>, BaseExporter<Metric>) that snapshot telemetry into the store;
• a DiagnosticListener subscriber that watches the Microsoft.EntityFrameworkCore diagnostic source and turns each command into a synthesised SQL span. EF Core payloads are read by reflection, so Telemetrix never forces an Entity Framework Core dependency on apps that do not use it.

UseTelemetrixDashboard() adds a terminal middleware that serves the embedded dashboard (HTML/CSS/JS compiled into the assembly) and a small JSON API. Requests outside the dashboard path pass straight through.

Everything is gated on IHostEnvironment.IsDevelopment(). Outside Development the registration calls are no-ops.

Configuration

builder.AddTelemetrix(options =>
{
    options.MaxTraces = 500;             // trace ring-buffer size
    options.MaxLogEntries = 2000;        // log ring-buffer size
    options.CaptureSqlParameters = true; // include bound SQL values
    options.CaptureCodeLocation = true;  // resolve the calling source line
    options.AddInstrumentation = true;   // set false if you configure OpenTelemetry yourself
});

app.UseTelemetrixDashboard(dashboard =>
{
    dashboard.Path = "/telemetrix";      // dashboard base path
    dashboard.RefreshIntervalMs = 2000;  // live-mode poll interval
    dashboard.AccentColor = "#6366f1";   // executive theme accent
});

Already configure OpenTelemetry yourself?

Use the lower-level API so Telemetrix does not add duplicate instrumentation:

builder.Services.AddTelemetrixCore();   // store + options + SQL capture only

builder.Services.AddOpenTelemetry()
    .WithTracing(t => t
        .AddAspNetCoreInstrumentation()
        .AddTelemetrixExporter());       // plug Telemetrix into your own pipeline

Sample application

samples/Telemetrix.Sample is a runnable ASP.NET Core + EF Core (SQLite) app. It exposes endpoints that exercise HTTP hierarchies, nested custom spans, EF Core queries and errors, and includes a background traffic generator so the dashboard has live data immediately.

dotnet run --project samples/Telemetrix.Sample

It opens /telemetrix automatically.

Build from source

dotnet build Telemetrix.slnx
dotnet test  Telemetrix.slnx

Notes

• Package versions in Directory.Packages.props are pinned to known-good OpenTelemetry releases. They are safe to bump to the latest on nuget.org.
• uPlot is loaded by the dashboard from a CDN. For fully offline use, drop uplot.js and uplot.css into src/Telemetrix/wwwroot/ — they are embedded automatically and served locally in preference to the CDN.
• The dashboard is unauthenticated and intended for local Development only. Enabling EnabledOutsideDevelopment is strongly discouraged.

Repository layout

src/Telemetrix            The library (NuGet package)
samples/Telemetrix.Sample Runnable ASP.NET Core + EF Core demo
tests/Telemetrix.Tests    xUnit unit tests

License

MIT — see LICENSE.