AutoConfiguredOpenTelemetrySdkBuilder does not set GlobalOpenTelemetry by default

[jack-berg]

GlobalOpenTelemetry makes you opt into initializing with autoconfigure by setting a environment variable / system property.

In contrast, AutoConfiguredOpenTelemetrySdk will set GlobalOpenTelemetry by default. This PR aligns AutoConfiguredOpenTelemetrySdk with the opt-in behavior of GlobalOpenTelemetry, and also with our general advice discouraging use of GlobalOpenTelemetry.

Also, this PR changes AutoConfiguredOpenTelemetrySdkBuilder#setResultAsGlobal(boolean) to simply be AutoConfiguredOpenTelemetrySdkBuilder#setResultAsGlobal(). This means there is no option to undo a decision to setResultAsGlobal after its previously been invoked.

This aligns with our builders elsewhere.

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.03 ⚠️

Comparison is base (cb6d713) 91.40% compared to head (eba323c) 91.38%.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #5564      +/-   ##
============================================
- Coverage     91.40%   91.38%   -0.03%     
+ Complexity     4963     4961       -2     
============================================
  Files           550      550              
  Lines         14569    14569              
  Branches       1358     1358              
============================================
- Hits          13317    13314       -3     
- Misses          866      868       +2     
- Partials        386      387       +1     

Impacted Files	Coverage Δ
.../autoconfigure/AutoConfiguredOpenTelemetrySdk.java	100.00% <100.00%> (ø)
...nfigure/AutoConfiguredOpenTelemetrySdkBuilder.java	94.40% <100.00%> (-1.87%)	⬇️

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[jkwatson]

👍🏽

[gabrieljones]

@jack-berg
https://opentelemetry.io/docs/concepts/instrumentation/libraries/#getting-a-tracer
This does the opposite of discouraging use of GlobalOpenTelemetry.

[jack-berg]

Yikes @gabrieljones. I'll open an issue / PR to fix that.

[jack-berg]

See issue open-telemetry/opentelemetry.io#3692.

[gabrieljones]

Edit:
Oh I see, the warning is triggered because something somewhere is calling GlobalOpentelemetry.get()

If I get rid of all of those then the warning should go away.

Original:
Hmmm, the

AutoConfiguredOpenTelemetrySdk found on classpath but automatic configuration is disabled.

warning also seems to "encourage" the use of GlobalOpenTelemetry.

Attempting to resolve this warning led me into a head on collision with the advice not to use GlobalOpenTelemetry.

Is there a way to suppress this warning so that the users of my app are not spooked.

Right now I do:

    val openTelemetry: OpenTelemetry = AutoConfiguredOpenTelemetrySdk.builder.build().getOpenTelemetrySdk

Is there a more correct way to retrieve a non Global instance of OpenTelemetry from AutoConfiguredOpenTelemetrySdk so that the warning is not triggered?

[jack-berg]

Oh I see, the warning is triggered because something somewhere is calling GlobalOpentelemetry.get()
If I get rid of all of those then the warning should go away.

Yup - maybe we should log something more clear / actionable 🤔