Add jaeger support for ctxtags extraction

[vporoshok]

No description provided.

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[vporoshok]

I signed it!

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CLAs look good, thanks!

[codecov-io]

Codecov Report

Merging #147 into master will increase coverage by 0.1%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #147     +/-   ##
=========================================
+ Coverage   73.23%   73.33%   +0.1%     
=========================================
  Files          36       36             
  Lines        1300     1305      +5     
=========================================
+ Hits          952      957      +5     
  Misses        300      300             
  Partials       48       48

Impacted Files	Coverage Δ
tracing/opentracing/id_extract.go	84.61% <100%> (+9.61%)	⬆️

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[domgreen]

Would you mind adding a few tests around id_extract.go just so that nothing regresses in the future 👍

[vporoshok]

Yeah, sure! Give few minutes!

[domgreen]

Thank you 😀

[jutkko]

Extraordinary cases? Maybe special cases?

[domgreen]

Under what circumstance would this happen? (I'm not very familiar with Jaeger)

[vporoshok]

I have not encountered such cases, so I left this comment

[jutkko]

If that's the case, why don't you just error or log instead of letting it through.

[vporoshok]

Is it ok if only normal case would be handled?

[domgreen]

Did you manage to get a failing test first? I'm not convinced that there would be a failing test if we removed the code in id_extract.go.

[vporoshok]

thank you for your patience, I hope that I managed to find optimal solution for testing this functionality

[vporoshok]

Thank you!