Kamon OpenTelemetry Trace Exporter

Provides a OpenTelemetry (OTLP) exporter for Kamon spans

The reporter relies on the opentelemetry-proto library for the gRPC communication with an OpenTelemetry (OTLP) service.

Local testing

To see the results of the exporter one can runt it against an instance of the OpenTelemetry Collector.
The collector can be started in a container, configured to receive gRPC calls with trace data. Run the script

./otel-collector.sh

If will start the OTEL Collector, configured for port 55690 and only to log all received traces. The run the test application which generates one single trace with three spans (incoming/request and two client spans)

sbt app/run

This would log something like

[main] INFO org.dmonix.kamon.otel.OpenTelemetryTraceReporter -  Creating OpenTelemetry Trace Reporter
[main] INFO org.dmonix.kamon.otel.OpenTelemetryTraceReporter - Configured endpoint for OTLP trace reporting [http://localhost:55690]

and in the collector the received spans are logged

2021-03-23T08:32:53.365Z        INFO    loggingexporter/logging_exporter.go:327 TracesExporter  {"#spans": 3}
2021-03-23T08:32:53.365Z        DEBUG   loggingexporter/logging_exporter.go:366 ResourceSpans #0
Resource labels:
     -> service.name: STRING(otlp-test-app)
     -> telemetry.sdk.name: STRING(kamon)
     -> telemetry.sdk.language: STRING(scala)
     -> telemetry.sdk.version: STRING(2.1.12)
     -> service.instance.id: STRING(xxx-yyy)
     -> env: STRING(staging)
     -> service.namespace: STRING(namespace-1)
     -> service.version: STRING(x.x.x)
InstrumentationLibrarySpans #0
InstrumentationLibrary kamon 2.1.12
Span #0
    Trace ID       : c2f8723d98431a6867ec0f4c416da008
    Parent ID      : 
    ID             : 00c76be115219aa8
    Name           : /purchase-item/{id}
    Kind           : SPAN_KIND_PRODUCER
    Start time     : 2021-03-23 08:32:48.218734795 +0000 UTC
    End time       : 2021-03-23 08:32:48.972185679 +0000 UTC
    Status code    : STATUS_CODE_OK
    Status message : 
Attributes:
     -> method: STRING(POST)
Span #1
    Trace ID       : c2f8723d98431a6867ec0f4c416da008
    Parent ID      : 00c76be115219aa8
    ID             : 1fd240d8d4635441
    Name           : add-order
    Kind           : SPAN_KIND_CLIENT
    Start time     : 2021-03-23 08:32:48.726453188 +0000 UTC
    End time       : 2021-03-23 08:32:48.971912872 +0000 UTC
    Status code    : STATUS_CODE_OK
    Status message : 
Attributes:
     -> method: STRING(put)
Span #2
    Trace ID       : c2f8723d98431a6867ec0f4c416da008
    Parent ID      : 00c76be115219aa8
    ID             : 5cc1fc597e1d7841
    Name           : check-credits
    Kind           : SPAN_KIND_CLIENT
    Start time     : 2021-03-23 08:32:48.231882663 +0000 UTC
    End time       : 2021-03-23 08:32:48.720293579 +0000 UTC
    Status code    : STATUS_CODE_OK
    Status message : 
Attributes:
     -> method: STRING(query)