Sidekiq instrumentation not creating child spans with SDK 1.2.1

[bolandoboy]

Hi! I'm using the Sidekiq instrumentation with the option propagation_style: :child. This works fine with opentelemetry-sdk 1.2.0 but fails when upgrading to 1.2.1.

"Fails" here means that spans are not exported, tested with a minimal example using the console exporter.

Tracking down the problem, I think it all comes down to the same root cause of #535

1. opentelemetry-sdk 1.2.1 introduced this check in OpenTelemetry::SDK::Trace::Tracer#start_span (MR here):

https://github.com/open-telemetry/opentelemetry-ruby/blob/1159ec04aa62168c6a841273401b71c325fa5986/sdk/lib/opentelemetry/sdk/trace/tracer.rb#L32

2. In the Sidekiq instrumentation, unless you use the option trace_processor_process_one: true, the context is set as untraced:

opentelemetry-ruby-contrib/instrumentation/sidekiq/lib/opentelemetry/instrumentation/sidekiq/patches/processor.rb

Line 16 in cc244b9

if instrumentation_config[:trace_processor_process_one]

3. By the time the process span is going to be created, extracted_context is untraced. (Please note that for the default propagation_style: :link a new root span with its own context is created, and that works)

opentelemetry-ruby-contrib/instrumentation/sidekiq/lib/opentelemetry/instrumentation/sidekiq/middlewares/server/tracer_middleware.rb

Line 33 in cc244b9

if instrumentation_config[:propagation_style] == :child

4. So for child spans tracer.in_span is used, which ends up calling the SDK start_span from point 1, which follow the untraced branch and, long story short, ends up creating a OpenTelemetry::Trace::Span instead of an OpenTelemetry::SDK::Trace::Span

OpenTelemetry::Trace::Span does nothing on finish, and spans are silently dropped:

https://github.com/open-telemetry/opentelemetry-ruby/blob/1159ec04aa62168c6a841273401b71c325fa5986/api/lib/opentelemetry/trace/span.rb#L154

(Edit: Not sure why some links are showing as snippets and others as huge links, sorry about that)

[arielvalentin]

Related open-telemetry/opentelemetry-ruby#1495

[github-actions]

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[KirillKayumov]

Upgrading to 'opentelemetry-instrumentation-sidekiq', '0.24.4' fixes the problem. Fix was added in #580

[github-actions]

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