OpenTelemetry parity with LaunchPad.Telemetry

OpenTelemetry parity with LaunchPad.Telemetry

Rocket.Surgery.LaunchPad.Telemetry offered six convention abstractions, a default convention that turned OpenTelemetry on, and a default convention for the resource. Joinery.Dovetail.OpenTelemetry (with the joints Joinery.Dovetail.Hosting emits) covers all of that, so an application can drop the LaunchPad package. This page is the written check, made against OpenTelemetry SDK 1.20.1, and names the test that shows each row. See OpenTelemetry for how the joints work.

The one LaunchPad.Telemetry convention that has no equivalent here is the instrumentation convention (HTTP client tracing, and HTTP client, runtime and process metrics). Dovetail’s package ships no instrumentation on purpose, so LaunchPad keeps it as a joint of its own in LaunchPad.Hosting (LaunchPad#3061).

The six abstractions

LaunchPad.Telemetry	Dovetail	Registered with	Shown by
IOpenTelemetryConvention, OpenTelemetryConvention	IOpenTelemetryJoint, OpenTelemetryJointDelegate (IOpenTelemetryBuilder)	ConfigureOpenTelemetry	Base_Joint_Configures_Services_And_Every_Signal
IOpenTelemetryAsyncConvention, OpenTelemetryAsyncConvention	IOpenTelemetryAsyncJoint, OpenTelemetryAsyncJointDelegate (generated)	ConfigureOpenTelemetry with an async delegate	Async_Delegate_Is_Awaited_With_The_Cancellation_Token_Given_To_ConfigureDovetail, Exported_Async_Joint_Is_Discovered_And_Awaited
IOpenTelemetryLoggingConvention, OpenTelemetryLoggingConvention	ILoggerProviderBuilderJoint, LoggerProviderJointDelegate (LoggerProviderBuilder)	ConfigureLoggerProvider	Exported_Logger_Joint_Is_Discovered_And_Applied, Logs_Are_Exported_Through_The_Logging_Provider
IOpenTelemetryMetricsConvention, OpenTelemetryMetricsConvention	IMeterProviderBuilderJoint, MeterProviderJointDelegate (MeterProviderBuilder)	ConfigureMeterProvider	Exported_Meter_Joint_Is_Discovered_And_Applied
IOpenTelemetryResourceConvention, OpenTelemetryResourceConvention	IResourceBuilderJoint, ResourceBuilderJointDelegate (ResourceBuilder)	ConfigureResourceBuilder	Exported_Resource_Joint_Is_Discovered_And_Applied_To_Every_Provider
IOpenTelemetryTracingConvention, OpenTelemetryTracingConvention	ITracerProviderJoint, TracerProviderJointDelegate (TracerProviderBuilder)	ConfigureTracerProvider	DovetailExport_Annotated_TracerJoint_Is_Auto_Discovered_Without_Manual_Configure
TelemetryConvention (applies the conventions, adds the logger)	DovetailOpenTelemetryJoint and its siblings, emitted by Joinery.Dovetail.Hosting	nothing: emitted into the application	Starting_The_Host_Starts_Traces_And_Metrics_With_The_Resource, Starting_The_Web_Application_Starts_Every_Signal_With_The_Resource
DefaultTelemetryConvention (resource defaults)	nothing: the SDK’s default resource	nothing	Resource defaults

How the shape differs, none of it a capability:

• A joint receives the IDovetailContext where a convention received the context and an IConfiguration. The configuration is context.Configuration (Joints_Read_The_Application_Configuration_From_The_Context).
• Delegates always take the context: write (_, builder) => ... where LaunchPad also had Action<TBuilder> overloads.
• ConfigureOpenTelemetryLogging, ConfigureOpenTelemetryMetrics and ConfigureOpenTelemetryTracing are ConfigureLoggerProvider, ConfigureMeterProvider and ConfigureTracerProvider; the resource one is ConfigureResourceBuilder.
• The base joint types and ConfigureOpenTelemetry are in Joinery.Dovetail.Joints, the narrower ones in Joinery.Dovetail.OpenTelemetry.Joints. Import both.
• [ExportConvention] is [DovetailExport]. ConventionCategory and AfterConvention<T> become the priority and category parameters, and every OpenTelemetry joint, base or narrow, runs in the one priority order.
• LaunchPad’s SerilogTelemetryConvention (Serilog’s OpenTelemetry sink) belongs to the Serilog package, not this one.

Logs through the logging provider

LaunchPad’s TelemetryConvention was also an ILoggingConvention that called ILoggingBuilder.AddOpenTelemetry(), so the OpenTelemetry provider was always one of the application’s logger providers.

Dovetail adds it when something configures logging. Every ILoggerProviderBuilderJoint (and ConfigureLoggerProvider) runs inside IOpenTelemetryBuilder.WithLogging, which in SDK 1.20.1 does AddLogging(logging => logging.UseOpenTelemetry(...)), and so does the UseOtlpExporter() call, which enables logging, metrics and tracing together. An application with neither has no log exporter, so it had nothing to export. To have the provider regardless, call WithLogging() from any OpenTelemetry joint.

Logs_Are_Exported_Through_The_Logging_Provider shows the result: the provider is an OpenTelemetryLoggerProvider among the host’s ILoggerProviders, and a warning written through ILogger<T> reaches the exporter with its category, level, body and structured state.

Log export keeps working when the Serilog joint is also applied: Serilog’s logger forwards each event to the other logging providers of the container, the OpenTelemetry one included (the other logging providers).

Resource defaults

Yes: the SDK’s default resource already holds what LaunchPad’s DefaultTelemetryConvention added. ResourceBuilder.CreateDefault() is the default resource, AddTelemetrySdk() and AddEnvironmentVariableDetector(), and every provider starts from it, so a joint only adds to it. Dovetail adds no resource defaults of its own.

• Default_Resource_Has_The_Telemetry_Sdk_Attributes_On_Every_Signal: with no resource joint, the tracer, meter and logger providers all carry telemetry.sdk.name, telemetry.sdk.language and telemetry.sdk.version, and service.name is unknown_service:<process>.
• Default_Resource_Has_The_Environment_Variable_Detector and Default_Resource_Reads_The_Process_Environment: OTEL_SERVICE_NAME and OTEL_RESOURCE_ATTRIBUTES set the resource, whether they come from the host’s configuration (the detector reads that first) or from the process environment.
• LaunchPads_Default_Resource_Convention_Changes_Nothing: adding AddTelemetrySdk().AddEnvironmentVariableDetector() through a resource joint produces exactly the same attributes on every provider.
• Blazor WebAssembly’s LaunchPad default only added AddTelemetrySdk(). The browser has the same default resource (Should_Have_The_Default_Resource_On_Every_Provider); it has no process environment, so the detector only reads configuration.

To name the service, set OTEL_SERVICE_NAME or call AddService(...) from a resource joint; LaunchPad’s convention only had that call commented out.

Hosts

Host	Shown by
Generic host	OpenTelemetryParityTests and OpenTelemetryBridgeTests in Joinery.Dovetail.OpenTelemetry.Tests, on .NET 10 and 11
ASP.NET Core	OpenTelemetryAspNetCoreTests in Joinery.Dovetail.Hosting.AspNetCore.Tests: every signal and the resource once the web host starts, the default resource, and on .NET 11 a request traced without tracer configuration
Blazor WebAssembly	BrowserHostingTests and BrowserOpenTelemetryTests in Joinery.Dovetail.WebAssembly.Hosting.Tests: traces, metrics and logs exported in a real browser, with the resource on each provider

The browser tests run the sample’s net11.0-browser build behind the Blazor Gateway, so they run on .NET 11 only.