Additional context protections

[joe-elliott]

Which problem is this PR solving?

• Fixes DATA RACE : span.context overwritten in span.SetBaggageItem() without any guards #526

Short description of the changes

• Made isWriteable() and isSamplingFinalized() methods on SpanContext
• Changed setTagInternal() and applySamplingDecision() to retrieve the context appropriately under lock or not
• Changed setSamplingPriority() to take a *samplingState and other required params
• Reenabled and extended TestSpanContextRaces()

Benchmarks

branch

goos: linux
goarch: amd64
pkg: github.com/uber/jaeger-client-go
BenchmarkTracer/sampler=NeverSample/remoteSampler=false/children=false/tags=5/ops=10/cpus-8         	 4943131	       245 ns/op
BenchmarkTracer/sampler=NeverSample/remoteSampler=false/children=true/tags=5/ops=10/cpus-8          	 3944086	       348 ns/op
BenchmarkTracer/sampler=AlwaysSample/remoteSampler=false/children=false/tags=5/ops=10/cpus-8        	 3023574	       400 ns/op
BenchmarkTracer/sampler=AlwaysSample/remoteSampler=false/children=true/tags=5/ops=10/cpus-8         	 2553519	       472 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleNoLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8         	 1532324	       730 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleNoLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8          	 3645086	       337 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleNoLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8        	  805288	      1443 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleNoLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8         	 1786104	       727 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleWithLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8       	  650238	      1788 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleWithLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8        	  619460	      1840 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleWithLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8      	  594268	      1816 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleWithLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8       	  561058	      1903 ns/op
PASS

master

goos: linux
goarch: amd64
pkg: github.com/uber/jaeger-client-go
BenchmarkTracer/sampler=NeverSample/remoteSampler=false/children=false/tags=5/ops=10/cpus-8         	 6046756	       203 ns/op
BenchmarkTracer/sampler=NeverSample/remoteSampler=false/children=true/tags=5/ops=10/cpus-8          	 4618400	       261 ns/op
BenchmarkTracer/sampler=AlwaysSample/remoteSampler=false/children=false/tags=5/ops=10/cpus-8        	 3357320	       361 ns/op
BenchmarkTracer/sampler=AlwaysSample/remoteSampler=false/children=true/tags=5/ops=10/cpus-8         	 2852832	       422 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleNoLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8         	 1490359	       861 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleNoLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8          	 4337530	       283 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleNoLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8        	 1000000	      1064 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleNoLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8         	 1964678	       662 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleWithLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8       	  753090	      1496 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleWithLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8        	  763476	      1584 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleWithLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8      	  735798	      1544 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleWithLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8       	  674318	      1606 ns/op
PASS

[codecov]

Codecov Report

Merging #544 into master will increase coverage by 0.05%.
The diff coverage is 92.50%.

@@            Coverage Diff             @@
##           master     #544      +/-   ##
==========================================
+ Coverage   88.46%   88.51%   +0.05%     
==========================================
  Files          61       61              
  Lines        3285     3301      +16     
==========================================
+ Hits         2906     2922      +16     
  Misses        252      252              
  Partials      127      127              

Impacted Files	Coverage Δ
tracer.go	95.53% <66.66%> (+0.02%)	⬆️
span.go	97.04% <96.77%> (+0.18%)	⬆️
span_context.go	93.96% <100.00%> (+0.16%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9a2c34e...1be7d73. Read the comment docs.

[yurishkuro]

As I understand this supersedes #528?

[joe-elliott]

New benchmarks with additional protection in reportSpan():

goos: linux
goarch: amd64
pkg: github.com/uber/jaeger-client-go
BenchmarkTracer/sampler=NeverSample/remoteSampler=false/children=false/tags=5/ops=10/cpus-8         	 4969408	       236 ns/op
BenchmarkTracer/sampler=NeverSample/remoteSampler=false/children=true/tags=5/ops=10/cpus-8          	 3820220	       305 ns/op
BenchmarkTracer/sampler=AlwaysSample/remoteSampler=false/children=false/tags=5/ops=10/cpus-8        	 2593363	       400 ns/op
BenchmarkTracer/sampler=AlwaysSample/remoteSampler=false/children=true/tags=5/ops=10/cpus-8         	 2531154	       456 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleNoLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8         	 1544758	       729 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleNoLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8          	 3588688	       340 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleNoLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8        	 1000000	      1374 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleNoLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8         	 1494066	       756 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleWithLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8       	  605941	      1830 ns/op
BenchmarkTracer/sampler=AdaptiveNeverSampleWithLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8        	  599637	      1904 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleWithLateBinding/remoteSampler=false/children=false/tags=5/ops=10/cpus-8      	  587407	      1871 ns/op
BenchmarkTracer/sampler=AdaptiveAlwaysSampleWithLateBinding/remoteSampler=false/children=true/tags=5/ops=10/cpus-8       	  756658	      1432 ns/op
PASS

[yurishkuro]

Thanks!