OTel span support

[sdaubin]

Overview

The java agent supports auto configuring the OTel SDK to report data to New Relic. Spans that are created with the span api are orphaned from New Relic data structures though. This returns spans backed by NR traces to generate metric and DT data.

This change hooks the SdkTracerProvider.tracerBuilder method and returns our tracer builder. When spans are started, we attempt to create a tracer. If successful, we return a Span implementation backed by the tracer, otherwise we return a no op span.

There is some special logic based on the span kind:

consumer

We start an OtherTransaction for consumer span kind.

server

We start a transaction for server spans and turn it into a web transaction.

client

For client spans, we either turn it into a database span or an external based on the span attributes.

Configuration

opentelemetry.sdk.spans.enabled can be use to disable the span behavior.
opentelemetry.instrumentation.{instrumentation-scope}.enabled can be used to disable spans for a specific Opentelemetry library

Related Github Issue

Include a link to the related GitHub issue, if applicable

Testing

The agent includes a suite of tests which should be used to
verify your changes don't break existing functionality. These tests will run with
Github Actions when a pull request is made. More details on running the tests locally can be found
here,

Checks

• Your contributions are backwards compatible with relevant frameworks and APIs.
• Your code does not contain any breaking changes. Otherwise please describe.
• Your code does not introduce any new dependencies. Otherwise please describe.

[sdaubin]

The createSegment API still generates an asynchronous tracer, which is not what we want. And from the bridge there's no easy way to register a signature to get a signatureId. This was the easiest way to get a normal, synchronous tracer.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 35.71429% with 27 lines in your changes missing coverage. Please review.

Project coverage is 70.56%. Comparing base (85e2eea) to head (972a16c).

Files	Patch %	Lines
...java/com/newrelic/agent/tracers/DefaultTracer.java	69.23%	1 Missing and 3 partials ⚠️
...ain/java/com/newrelic/agent/bridge/ExitTracer.java	0.00%	3 Missing ⚠️
...elic/agent/bridge/datastore/SqlQueryConverter.java	0.00%	3 Missing ⚠️
...ava/com/newrelic/agent/database/SqlObfuscator.java	25.00%	3 Missing ⚠️
...elic/agent/service/analytics/SpanEventFactory.java	50.00%	2 Missing and 1 partial ⚠️
...ava/com/newrelic/agent/tracers/AbstractTracer.java	0.00%	3 Missing ⚠️
...n/java/com/newrelic/agent/bridge/TracedMethod.java	0.00%	2 Missing ⚠️
...lic/agent/instrumentation/InstrumentationImpl.java	0.00%	2 Missing ⚠️
...gent/instrumentation/pointcuts/XmlRpcPointCut.java	0.00%	2 Missing ⚠️
...ava/com/newrelic/agent/bridge/Instrumentation.java	0.00%	1 Missing ⚠️
... and 1 more

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1886      +/-   ##
============================================
- Coverage     70.61%   70.56%   -0.05%     
- Complexity     9860     9864       +4     
============================================
  Files           827      831       +4     
  Lines         39857    39894      +37     
  Branches       6068     6072       +4     
============================================
+ Hits          28144    28153       +9     
- Misses         8983     9008      +25     
- Partials       2730     2733       +3     

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[jasonjkeller]

While this PR has been reviewed and approved, I'm changing it to a draft to prevent merging as there are ongoing discussions about the broader OTel strategy across APM and we want to make sure that all teams are in alignment on an approach.