Proof of concept: Named Tracers / TracerFactory

[z1c0]

This draft shows a possible implementation of the Named Tracers RFC (open-telemetry/oteps#16).

Instead of working with a single global Tracer object, tracers must be created using a factory-pattern approach for a given tracer name.

The LoggingTracer.Demo.AspNetCore application already makes uses of the ITracerFactory and produces log output using the tracer name as a logging prefix:

           2 |        1 | TracerFactory.Create(OpenTelemetry.Collector.AspNetCore)
Hosting environment: Production
Content root path: C:\workspaces\git\Dynatrace\opentelemetry-dotnet\samples\LoggingTracer\LoggingTracer.Demo.AspNetCore
Now listening on: http://localhost:5000
Now listening on: https://localhost:5001
Application started. Press Ctrl+C to shut down.
       12185 |        6 | LoggingTextFormat.Extract(...)
       12186 |        6 | Tracer(OpenTelemetry.Collector.AspNetCore).SpanBuilder(/)
       12186 |        6 | SpanBuilder.ctor(/)
       12187 |        6 | Span.ctor(/, Internal)
       12187 |        6 | SpanBuilder.SetSpanKind(Server)
       12187 |        6 | SpanBuilder.SetSampler(AlwaysSampleSampler)
       12188 |        6 | SpanBuilder.SetParent(SpanContext{TraceId=00000000000000000000000000000000, SpanId=0000000000000000, TraceOptions=None})
       12189 |        6 | SpanBuilder.StartSpan()
       12189 |        6 | Tracer(OpenTelemetry.Collector.AspNetCore).WithSpan
       12190 |        6 | Span.SetAttribute(http.host, localhost:5001)
       12190 |        6 | Span.SetAttribute(http.method, GET)
       12190 |        6 | Span.SetAttribute(http.path, /)
       12192 |        6 | Span.SetAttribute(http.user_agent, Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36)
       12194 |        6 | Span.SetAttribute(http.url, https://localhost:5001/)
       12214 |        6 | Span.SetAttribute(http.status_code, 200)
       12215 |        6 | Span.End, Name: /
       12421 |       10 | LoggingTextFormat.Extract(...)
       12422 |       10 | Tracer(OpenTelemetry.Collector.AspNetCore).SpanBuilder(/favicon.ico)
       12422 |       10 | SpanBuilder.ctor(/favicon.ico)
       12422 |       10 | Span.ctor(/favicon.ico, Internal)
       12423 |       10 | SpanBuilder.SetSpanKind(Server)
       12423 |       10 | SpanBuilder.SetSampler(AlwaysSampleSampler)
       12424 |       10 | SpanBuilder.SetParent(SpanContext{TraceId=00000000000000000000000000000000, SpanId=0000000000000000, TraceOptions=None})
       12425 |       10 | SpanBuilder.StartSpan()
       12425 |       10 | Tracer(OpenTelemetry.Collector.AspNetCore).WithSpan
       12426 |       10 | Span.SetAttribute(http.host, localhost:5001)
       12426 |       10 | Span.SetAttribute(http.method, GET)
       12426 |       10 | Span.SetAttribute(http.path, /favicon.ico)
       12427 |       10 | Span.SetAttribute(http.user_agent, Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36)
       12427 |       10 | Span.SetAttribute(http.url, https://localhost:5001/favicon.ico)
       12427 |       10 | Span.SetAttribute(http.status_code, 200)
       12427 |       10 | Span.End, Name: /favicon.ico
       26840 |       10 | LoggingTextFormat.Extract(...)
       26840 |       10 | Tracer(OpenTelemetry.Collector.AspNetCore).SpanBuilder(/bla)
       26841 |       10 | SpanBuilder.ctor(/bla)
       26841 |       10 | Span.ctor(/bla, Internal)
       26841 |       10 | SpanBuilder.SetSpanKind(Server)
       26842 |       10 | SpanBuilder.SetSampler(AlwaysSampleSampler)
       26842 |       10 | SpanBuilder.SetParent(SpanContext{TraceId=00000000000000000000000000000000, SpanId=0000000000000000, TraceOptions=None})
       26842 |       10 | SpanBuilder.StartSpan()
       26843 |       10 | Tracer(OpenTelemetry.Collector.AspNetCore).WithSpan
       26843 |       10 | Span.SetAttribute(http.host, localhost:5001)
       26843 |       10 | Span.SetAttribute(http.method, GET)
       26844 |       10 | Span.SetAttribute(http.path, /bla)
       26844 |       10 | Span.SetAttribute(http.user_agent, Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36)
       26844 |       10 | Span.SetAttribute(http.url, https://localhost:5001/bla)
       26845 |       10 | Span.SetAttribute(http.status_code, 200)
       26845 |       10 | Span.End, Name: /bla
       26938 |        7 | LoggingTextFormat.Extract(...)
       26938 |        7 | Tracer(OpenTelemetry.Collector.AspNetCore).SpanBuilder(/favicon.ico)
       26939 |        7 | SpanBuilder.ctor(/favicon.ico)
       26939 |        7 | Span.ctor(/favicon.ico, Internal)
       26940 |        7 | SpanBuilder.SetSpanKind(Server)
       26940 |        7 | SpanBuilder.SetSampler(AlwaysSampleSampler)
       26941 |        7 | SpanBuilder.SetParent(SpanContext{TraceId=00000000000000000000000000000000, SpanId=0000000000000000, TraceOptions=None})
       26941 |        7 | SpanBuilder.StartSpan()
       26942 |        7 | Tracer(OpenTelemetry.Collector.AspNetCore).WithSpan
       26943 |        7 | Span.SetAttribute(http.host, localhost:5001)
       26943 |        7 | Span.SetAttribute(http.method, GET)
       26943 |        7 | Span.SetAttribute(http.path, /favicon.ico)
       26943 |        7 | Span.SetAttribute(http.user_agent, Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/76.0.3809.100 Safari/537.36)
       26944 |        7 | Span.SetAttribute(http.url, https://localhost:5001/favicon.ico)
       26945 |        7 | Span.SetAttribute(http.status_code, 200)
       26945 |        7 | Span.End, Name: /favicon.ico

[austinlparker]

I forget what happened here, but these commits got eaten somehow - could this get recreated?

[z1c0]

This was just a proof-of-concept implementation of the Named Tracers RFC (open-telemetry/oteps#16).
Until some progress is made on this RFC I will close the PR.