Close the span writer on main

[jpkrohling]

Signed-off-by: Juraci Paixão Kröhling [email protected]

Which problem is this PR solving?

• Fixes Panic on close of closed channel #2094

Short description of the changes

• Previously, the span writer was being closed twice when the all-in-one was being used: once from the all-in-one main, and one from the collector's #Close. This PR makes the party that creates the span writer responsible for closing it.

[codecov]

Codecov Report

Merging #2096 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2096      +/-   ##
==========================================
+ Coverage   96.31%   96.33%   +0.01%     
==========================================
  Files         214      214              
  Lines       10535    10537       +2     
==========================================
+ Hits        10147    10151       +4     
+ Misses        330      328       -2     
  Partials       58       58

Impacted Files	Coverage Δ
plugin/storage/cassandra/spanstore/writer.go	100% <100%> (ø)	⬆️
...lugin/sampling/strategystore/adaptive/processor.go	100% <0%> (+0.79%)	⬆️

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[yurishkuro]

what about all-in-one, should it have similar code?

[jpkrohling]

It does already, which is the cause for the double-close:

jaeger/cmd/all-in-one/main.go

Lines 155 to 160 in 74856ef

	if closer, ok := spanWriter.(io.Closer); ok {
	err := closer.Close()
	if err != nil {
	logger.Error("Failed to close span writer", zap.Error(err))
	}
	}