Dosaic.Extensions.Tracing 1.2.41

Dosaic.Extensions.Tracing

Compile-time OpenTelemetry tracing for Dosaic apps, woven by Metalama. No runtime DI, no reflection, no proxies — activities are emitted directly into your methods at build time and feed the shared Dosaic ActivitySource.

Install

<ItemGroup>
  <PackageReference Include="Dosaic.Extensions.Tracing" Version="1.0.0" />
</ItemGroup>

Adding the reference is enough: a transitive Metalama fabric traces your code according to the MSBuild properties below. No code changes required.

Configuration (MSBuild)

<PropertyGroup>
  <DosaicTracingMode>AllPublic</DosaicTracingMode>
  <DosaicTracingCaptureArgs>None</DosaicTracingCaptureArgs>
  <DosaicTracingCaptureArgsOnError>Json</DosaicTracingCaptureArgsOnError>
  <DosaicTracingInclude>MyApp.Features.*;MyApp.Services.*</DosaicTracingInclude>
  <DosaicTracingExclude>**.Migrations;**.Generated</DosaicTracingExclude>
</PropertyGroup>

Argument capture on error. Even with DosaicTracingCaptureArgs=None (the default), arguments are captured onto the span when a method throws, controlled by DosaicTracingCaptureArgsOnError (default ToString). When happy-path capture is already on, the error capture is skipped to avoid duplicate tags.

Attributes

• [Trace] — trace a single method, or every eligible instance method of a class. [Trace(CaptureArgs = ArgCaptureMode.Json)] overrides capture for that target.
• [NoTrace] — opt a class or method out of automatic tracing.
• [NoCapture] — opt a single parameter out of argument capture.

Parameters of these types are never captured: CancellationToken, Stream, byte[], ReadOnlyMemory<byte>, IServiceProvider, ClaimsPrincipal, HttpContext, IFormFile.

Enriching the current span

using Dosaic.Extensions.Tracing; adds static extension members to Dosaic.Hosting.Abstractions.Tracing, so you enrich Activity.Current directly off Tracing — no new activity is started:

Tracing.Tag("property.id", id);
Tracing.Event("PropertyLoaded");
Tracing.Error(ex);
Tracing.Link(otherActivityContext);

Tracing.Current returns the ambient activity (or null). All calls are no-ops when no activity is active.

Notes

• Json capture reuses Dosaic's shared SerializationExtensions.Serialize (System.Text.Json, camelCase, enums as strings, nulls ignored). It is not trimming / Native-AOT safe — prefer ToString under AOT.
• Argument capture never throws: if serialization fails (e.g. a reference cycle), the tag is set to <ExceptionTypeName> instead. A failed capture can never mask the method's own exception.
• Span names are TypeName.MethodName; all spans use the shared Dosaic ActivitySource.