Add RLock for RemotelyControlledSampler.sampler Resolves #514

[hummerd]

Serialize read access for RemotelyControlledSampler.sampler field

Signed-off-by: Dima Kozlov hummerd@mail.ru

Which problem is this PR solving?

Serialize access to RemotelyControlledSampler.sampler

Short description of the changes

Wrap sampler with atomic.Value.

[yurishkuro]

How about using a private struct samplerWrapper then?

type samplerWrapper struct {
  sampler Sampler
}

The concrete type stored in atomic.Value will be the same. Atomic value is much faster that full RW lock.

[hummerd]

Actually RLock is one atomic atomic.AddInt32 operation, until there is no write Lock() and write locks will happen not too often in our case.

But let it be wrapper =)

Do we need sync.Lock in remote RemotelyControlledSampler after that?

[yurishkuro]

You're right about RLock, let's keep it.

Please make sure the commits are signed.

[hummerd]

It is ready. WIth RLock and sign-off.

[codecov]

Codecov Report

Merging #515 into master will not change coverage.
The diff coverage is 50.00%.

@@           Coverage Diff           @@
##           master     #515   +/-   ##
=======================================
  Coverage   88.75%   88.75%           
=======================================
  Files          60       60           
  Lines        3790     3790           
=======================================
  Hits         3364     3364           
  Misses        309      309           
  Partials      117      117           

Impacted Files	Coverage Δ
sampler_remote.go	82.48% <50.00%> (ø)

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[yurishkuro]

Thanks!