Instrument View#render instead of DispatcherServlet#render

[videnkz]

Checklist

closes #811

• Implement code
• Add tests
  -- [x] jsp
  -- [x] markup templates
  -- [x] freemarker
  -- [x] groovy templates
  -- [x] jackson2json view
  -- [x] jade4j template
• Update documentation
• Update CHANGELOG.md
• Update supported-technologies.asciidoc
• Added an API method or config option? Document in which version this will be introduced.

[videnkz]

Hi @felixbarny ,
please review pull request.

[videnkz]

[codecov-io]

Codecov Report

Merging #829 into master will decrease coverage by 0.16%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             master     #829      +/-   ##
============================================
- Coverage      64.3%   64.13%   -0.17%     
  Complexity       84       84              
============================================
  Files           232      231       -1     
  Lines          9592     9353     -239     
  Branches       1275     1215      -60     
============================================
- Hits           6168     5999     -169     
+ Misses         3047     2973      -74     
- Partials        377      381       +4

Impacted Files	Coverage Δ	Complexity Δ
...co/elastic/apm/agent/servlet/ServletApiAdvice.java	7.5% <0%> (-0.1%)	0 <0> (ø)
.../apm/agent/report/serialize/DslJsonSerializer.java	86.08% <0%> (-3.63%)	0% <0%> (ø)
...m/agent/jms/JmsMessageListenerInstrumentation.java	23.8% <0%> (-1.2%)	0% <0%> (ø)
...lastic/apm/agent/jms/JmsInstrumentationHelper.java	100% <0%> (ø)	0% <0%> (ø)	⬇️
.../elastic/apm/agent/jms/BaseJmsInstrumentation.java	100% <0%> (ø)	0% <0%> (ø)	⬇️
...ic/apm/agent/jms/JmsInstrumentationHelperImpl.java	0% <0%> (ø)	0% <0%> (ø)	⬇️
.../elastic/apm/agent/jms/MessagingConfiguration.java
...m/agent/jms/JmsMessageConsumerInstrumentation.java	26.56% <0%> (+0.75%)	0% <0%> (ø)	⬇️
...agent/spring/webmvc/ViewRenderInstrumentation.java	50% <0%> (+11.9%)	0% <0%> (ø)	⬇️

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[felixbarny]

Awesome job! Sorry for the slow review.

[eyalkoren]

Well done, thanks!!

Two small suggestions.

Also, please merge and resolve conflicts so that we can run the tests.

[eyalkoren]

Great, thanks!
A few minor comments.
In addition, since the default of obtainSubtype is not tested, please add a small sanity test for this method only, eg obtainSubtype(MyCustomView) yielding MyCustom.

[felixbarny]

I've added the suggestions, hope you don't mind 🙂
Also found and fixed some edge cases which could lead to a StringIndexOutOfBoundsException for really strange class names and for those not containing "View".

[videnkz]

I've added the suggestions, hope you don't mind slightly_smiling_face
Also found and fixed some edge cases which could lead to a StringIndexOutOfBoundsException for really strange class names and for those not containing "View".

Thanks :)
I also thought about classes without packages

[felixbarny]

Thanks for bearing with us even if it sometimes takes some time to get changes in, but we really appreciate it!