Stats: improve JSON support, add missing structs

[aalekseevx]

Hi there! We are delighted to have the opportunity to utilize pion's webrtc-stats implementation for unmarshalling JSON stats at our backend. I have put in some effort to make it feasible and would love to contribute it.

Description:

• Fix json marshalling of stats containing enums
• Add UnmarshalStatsJSON helper
• Add marshalling/unmarshalling tests
• Add missing AudioSourceStats, VideoSourceStats, AudioPlayoutStats defined in https://www.w3.org/TR/webrtc-stats
• Deprecate ICECandidateStats' NetworkType, use plain string instead of enum which does not suite the definition: https://www.w3.org/TR/2018/WD-webrtc-stats-20180627/#rtcnetworktype-enum

[AbsoluteNikola]

Amazing feature. We really need this

[Sean-Der]

This looks great @aalekseevx lets get it merged!

I will review tonight. If you don’t hear from me please ping here and on https://pion.ly/slack

Lots of stuff going on sometimes get pulled away :/

[codecov]

Codecov Report

Patch coverage: 62.08% and project coverage change: -0.42% ⚠️

Comparison is base (6453346) 77.63% compared to head (ec5f6f2) 77.22%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2513      +/-   ##
==========================================
- Coverage   77.63%   77.22%   -0.42%     
==========================================
  Files          87       87              
  Lines        9378     9674     +296     
==========================================
+ Hits         7281     7471     +190     
- Misses       1666     1745      +79     
- Partials      431      458      +27     

Flag	Coverage Δ
go	78.88% <62.08%> (-0.52%)	⬇️
wasm	64.51% <0.00%> (-5.72%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
icegatherer.go	81.13% <ø> (-0.14%)	⬇️
stats.go	64.35% <59.20%> (-35.65%)	⬇️
datachannelstate.go	100.00% <100.00%> (ø)
dtlstransportstate.go	100.00% <100.00%> (ø)
icecandidatetype.go	81.81% <100.00%> (+2.87%)	⬆️
icerole.go	100.00% <100.00%> (ø)

... and 2 files with indirect coverage changes

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[aalekseevx]

@Sean-Der, hi! I made some fixes for CI checks, do you have some time to complete the review now?

[aalekseevx]

Any updates?

[Sean-Der]

Fantastic work @aalekseevx! sorry I didn't get a chance to review sooner

• Can we drop the dependency? Outside of tests we have 0 3rd party dependencies, would be nice to keep that :)

• Can you move the testdata into the files that use them? I don't feel strongly either way, I just would like to follow the established pattern.

Thank you so much for doing this work. It is a very important contribution. Sorry I did't respond sooner, personal life has just kept me busy. thank you!

[aalekseevx]

@Sean-Der, thanks a lot for the review! I'm glad you liked this piece of work. I have updated the PR to meet the requirements. Is it possible to make a release as soon as it is merged?

[aalekseevx]

@Sean-Der, are there any blockers to merge left? Is golangci-lint timeout a problem?

[Sean-Der]

@aalekseevx nope you did a great job! I will merge and tag today.

thank you for pinging me. This is super important contribution. Sorry I have been distracted with OBS dev.

[Sean-Der]

Merged and tagged with v3.2.15 thank you @aalekseevx !