undefined method attributes for #<OpenTelemetry::Trace::Span:...>

[yamagai]

Hello, thank you for creating such a great OSS!
but, I'm having a little trouble using this library.

In my application, I'm adding attributes to the root_span using add_attributes, and using those attributes to decide whether to generate a child_span or not like below. (using X-Ray)

OpenTelemetry::SDK.configure do |c|
  c.service_name = "name"
  c.add_span_processor(
    OpenTelemetry::SDK::Trace::Export::BatchSpanProcessor.new(
      OpenTelemetry::Exporter::OTLP::Exporter.new(
        endpoint: "http://xray.example.com"
      )
    )
  )
  c.id_generator = OpenTelemetry::Propagator::XRay::IDGenerator
  c.propagators = [OpenTelemetry::Propagator::XRay::TextMapPropagator.new]
end

tracer = OpenTelemetry.tracer_provider.tracer(name)
root_span = tracer.start_root_span("hoge")
root_span.set_attribute("fuga", fuga)

if root_span.attributes["fuga"].present?
  child_span = tracer.start_span(name, with_parent: OpenTelemetry.propagation.extract(carrier))
end

However, as shown below, when OpenTelemetry::SDK::Trace::Tracer#internal_start_span is called internally and recording? is false, a OpenTelemetry::Trace::Span instance is generated instead of an OpenTelemetry::SDK::Trace::Span.

• called OpenTelemetry::SDK::Trace::Tracer#internal_start_span

  • opentelemetry-ruby/sdk/lib/opentelemetry/sdk/trace/tracer.rb

    Line 37 in ad9a5c2

    @tracer_provider.internal_start_span(name, kind, attributes, links, start_timestamp, with_parent, @instrumentation_scope)

• generate OpenTelemetry::Trace::Span instance when recording? is false

  • opentelemetry-ruby/sdk/lib/opentelemetry/sdk/trace/tracer_provider.rb

    Line 161 in ad9a5c2

    OpenTelemetry::Trace.non_recording_span(OpenTelemetry::Trace::SpanContext.new(trace_id: trace_id, span_id: span_id, tracestate: result.tracestate))

This span does not have the attributes method and causes an error.
This is because the generated span is an instance of OpenTelemetry::Trace::Span, which does not define the attributes method.

This can cause problems when using a Sampler to sample the spans. Is there a way to handle this issue?

Should I avoid using a logic that checks the attributes of the root_span to determine whether to generate a child_span or not?
Personally, I feel a bit uneasy about OpenTelemetry::SDK::Trace::Tracer#internal_start_span generating an OpenTelemetry::Trace::Span.

Thank you for your help!

[yamagai]

as a current workaround, I'm avoiding this issue by including root_span.is_a?(OpenTelemetry::SDK::Trace::Span) as a condition in the if statement as follows.

if root_span.is_a?(OpenTelemetry::SDK::Trace::Span) && root_span.attributes["fuga"].present?
  child_span = tracer.start_span(name, with_parent: OpenTelemetry.propagation.extract(carrier))
end