EmberTrace.Testing 0.3.0

Русская версия: ./README.ru.md

EmberTrace

EmberTrace is a fast in-process tracer/profiler for .NET with minimal overhead on the hot path:

• Allocation-free Begin/End with a lock-free hot path (thread-local buffers; shared session state is touched only on chunk rotation and when a limit is configured)
• Flows for links between threads and async/await
• Offline analysis after stopping a session (aggregations + reports)
• Export to Chrome Trace (for chrome://tracing / Perfetto)
• Flight recorder - Tracer.Snapshot() dumps the last N seconds from a live session without stopping it
• Auto-instrumentation - [Trace] on a partial method generates the scope wrapper, the id and the metadata; [Trace] on a class generates a DI decorator for the whole service

Installation

The easiest option is the metapackage:

dotnet add package EmberTrace.All

If you install packages selectively:

• EmberTrace - runtime API (Tracer.*)
• EmberTrace.Abstractions - attributes ([assembly: TraceId(...)])
• EmberTrace.Generator - source generator (automatically registers metadata)
• EmberTrace.Analysis - session processing (session.Process())
• EmberTrace.ReportText - text report (TraceText.Write(...))
• EmberTrace.Export - Chrome Trace export (TraceExport.*)
• EmberTrace.Format - binary session persistence (TraceFormat.Write/Read)
• EmberTrace.OpenTelemetry - export to OpenTelemetry (Activity spans)
• EmberTrace.Extensions.Hosting - ASP.NET Core integration (AddEmberTrace(), request middleware, appsettings.json, /embertrace/dump)
• EmberTrace.Testing - performance assertions and baseline diffing for tests (stats.Scope(...), TraceBudget)
• EmberTrace.RoslynAnalyzers - analyzers and code fixes for correct usage (fixes run in IDE and are included in the package)

Quick Start

1. Define IDs and metadata (in any project file, at the assembly level):

using EmberTrace.Abstractions.Attributes;

[assembly: TraceId(1000, "App", "App")]
[assembly: TraceId(2000, "Worker", "Workers")]

2. Wrap the required sections in scopes:

using EmberTrace;

Tracer.Start();

using (Tracer.Scope(1000))
{
    // work
}

var session = Tracer.Stop();

3. Generate a report and/or export:

var processed = session.Process();
var meta = Tracer.CreateMetadata(); // if generator is used — metadata will be registered automatically

Console.WriteLine(TraceText.Write(processed, meta: meta, topHotspots: 20, maxDepth: 8));

using var fs = File.Create("out/trace.json");
TraceExport.WriteChromeComplete(session, fs, meta: meta);

4. Open out/trace.json:

• chrome://tracing (Chrome)
• Perfetto (web UI) - convenient for large traces

Repository Example

The most complete example is samples/EmberTrace.DocScreenshots (scopes + flows + async + export + text report):

dotnet run --project samples/EmberTrace.DocScreenshots -c Release
# files will be in samples/EmberTrace.DocScreenshots/out

Documentation

• Index
• Quick Start
• Usage and API
• Flow and async
• Export
• Analysis and reports
• Flight recorder
• Generator and metadata
• Auto-instrumentation with [Trace]
• Troubleshooting

Build and Tests

Requires the SDK specified in global.json.

dotnet build -c Release
dotnet test -c Release

Benchmarks and AOT

dotnet run --project benchmarks/EmberTrace.Benchmarks -c Release -- --filter *ScopeBenchmarks*

dotnet publish samples/EmberTrace.NativeAot -c Release -p:PublishAot=true

Screenshots

Example of a simple trace in Perfetto

Useful Links

• Documentation: docs/index.md
• Examples: samples/