Add MDCScopeManager for correlating logs with trace context

[avimas]

HI

I am new to Jaeger and this is an initial solution to #715 I'd like to know if this approach (warping the scope manager) is an acceptable solution.

Which problem is this PR solving?

• Resolves Add trace IDs into std logging (MDC) #715 add MDC support

Short description of the changes

• adding new MDC scope manager.

[codecov]

Codecov Report

Merging #718 into master will decrease coverage by 1.02%.
The diff coverage is 95.34%.

@@             Coverage Diff              @@
##             master     #718      +/-   ##
============================================
- Coverage     89.78%   88.76%   -1.03%     
- Complexity      590      596       +6     
============================================
  Files            70       73       +3     
  Lines          2164     2242      +78     
  Branches        284      289       +5     
============================================
+ Hits           1943     1990      +47     
- Misses          132      159      +27     
- Partials         89       93       +4     

Impacted Files	Coverage Δ	Complexity Δ
...ava/io/jaegertracing/internal/MDCScopeManager.java	95.34% <95.34%> (ø)	3.00 <3.00> (?)
...rtracing/internal/reporters/CompositeReporter.java	71.42% <0.00%> (-28.58%)	6.00% <0.00%> (-1.00%)
...a/io/jaegertracing/internal/clock/SystemClock.java	75.00% <0.00%> (-25.00%)	6.00% <0.00%> (+2.00%)	⬇️
...gertracing/internal/reporters/LoggingReporter.java	81.81% <0.00%> (-9.10%)	4.00% <0.00%> (-1.00%)
...egertracing/internal/propagation/TextMapCodec.java	92.72% <0.00%> (-1.82%)	35.00% <0.00%> (-1.00%)
...gertracing/internal/clock/MicrosAccurateClock.java	0.00% <0.00%> (ø)	0.00% <0.00%> (?%)
...ertracing/internal/clock/MillisAccurrateClock.java	100.00% <0.00%> (ø)	4.00% <0.00%> (?%)
...n/java/io/jaegertracing/internal/JaegerTracer.java	89.22% <0.00%> (+0.14%)	27.00% <0.00%> (ø%)

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[yurishkuro]

I thing it's a reasonable addition.

[pavolloffay]

Could you add a test with two spans created? The second span would be a child of the first one. Then after the second span is closed assert that MDC contains context from the parent.

[pavolloffay]

small nits, otherwise LGTM

[yurishkuro]

lgtm

[yurishkuro]

@pavolloffay do we have a way to disable style check for capital letters?

Abbreviation in name 'MDCScopeManager' must contain no more than '2' consecutive capital letters.

[pavolloffay]

I don't know

[avimas]

@yurishkuro changed the style check config to allow 4 consecutive letters, the build fails in codecov check now
anything I can do?

[yurishkuro]

I was thinking of whether we can disable the rule specifically for the two MDC classes, not globally for the project, do you know if it's possible?

[avimas]

@yurishkuro , Yes I added these classes to the suppressions.xml file
the build still fails in codecov I don't know why

[yurishkuro]

Thanks!

I am going to merge this, but could you please create another PR and add a section to the README about the new functionality?