Add stdout exporter example for Logs.

[lalitb]

Design discussion issue (if applicable) #

Changes

Add the stdout exporter example for Logs. The example will

• Initialize TraceProvider and LoggerProvider
• Initialize Tracer and Logger object
• Create Span, and make it active(current)
• Emit Log.
• Make the Span inactive (implicitly end/export it).

This will export the Span, along with the Log. The Log will have the trace_id and span_id of currently active span.
Output example:

{"resourceLogs":[{"resource":{"attributes":[{"key":"service.name","value":{"stringValue":"unknown_service"}}]},"scopeLogs":[{"scope":{"name":"stdout-test"},"logRecords":[{"severityNumber":9,"body":{"stringValue":"test log"},"attributes":[],"droppedAttributesCount":0,"flags":1,"spanId":"abf95442ac326a3b","traceId":"6b3271b5c619652bc28ad70810e7f131"}]}]}]}

{"resourceSpans":[{"resource":{"attributes":[{"key":"service.name","value":{"stringValue":"unknown_service"}}]},"scopeSpans":[{"scope":{"name":"stdout-test"},"spans":[{"traceId":"6b3271b5c619652bc28ad70810e7f131","spanId":"abf95442ac326a3b","parentSpanId":"","name":"test_span","kind":1,"startTimeUnixNano":1684817629827077900,"endTimeUnixNano":1684817629827244600,"attributes":[{"key":"test_key","value":{"stringValue":"test_value"}}],"droppedAttributesCount":0,"droppedEventsCount":0,"droppedLinksCount":0,"status":{}}]}]}]}

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[codecov]

Codecov Report

Patch and project coverage have no change.

Comparison is base (e9adef6) 50.9% compared to head (b5ca720) 50.9%.

Additional details and impacted files

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##            main   #1072   +/-   ##
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  Coverage   50.9%   50.9%           
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  Files        165     165           
  Lines      19689   19689           
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  Hits       10025   10025           
  Misses      9664    9664           

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[cijothomas]

I think we should not be showing this, as this is never intended for end-users to use like this. This could be part of a tutorial for "how to write own appenders", or shown with existing log api like in this PR: #1071

[lalitb]

Yes agree, but I think it is still helpful to have a vendor neutral example (with no external dependencies) using only core API and SDK - which would be useful to both - external developers who want to (somehow) use only the core api and sdk in their application, and the developers creating their own appenders/subscriber. We can add a disclaimer as comment for LogRecordBuilder that it is not recommended for front facing API if that helps.

Said that, I don't have strong opinion, and can close this PR if we all agree this not to be good showcase example :)

[cijothomas]

Options:

1. If the intended audience is authors of new appenders, cover it in the docs, no need of example.
2. Keep this, but explicitly warn at the top saying this is not for end users to call directly. They should use the existing Log APIs. (eg: slog,log,tracing...)

[jtescher]

I'd go for option 1 as that seems least confusing for lower context people.

[lalitb]

Closing this PR- as discussed, it is better to add documentation for Appender devs, instead of having a example.