Exclude $view proxies from JAX-RS instrumentation

[mdindoffer]

Excluding $view proxy classes prevents explosion of transaction names in certain scenarios, see #512.

[codecov-io]

Codecov Report

Merging #600 into master will not change coverage.
The diff coverage is n/a.

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  Coverage     63.13%   63.13%           
  Complexity       68       68           
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  Files           188      188           
  Lines          7278     7278           
  Branches        845      845           
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  Hits           4595     4595           
  Misses         2413     2413           
  Partials        270      270

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[eyalkoren]

Why do we capture them at all? Through a base servlet or servlet filter?

[felixbarny]

I guess these are just EJB proxies for the actual resource class. But maybe we should rather exclude those proxies globally here:

apm-agent-java/apm-agent-core/src/main/java/co/elastic/apm/agent/configuration/CoreConfiguration.java

Lines 229 to 246 in 4ab2b6f

	private final ConfigurationOption<List<WildcardMatcher>> classesExcludedFromInstrumentation = ConfigurationOption
	.builder(new ListValueConverter<>(new WildcardMatcherValueConverter()), List.class)
	.key("classes_excluded_from_instrumentation")
	.configurationCategory(CORE_CATEGORY)
	.tags("internal")
	.description("\n" +
	"\n" +
	WildcardMatcher.DOCUMENTATION)
	.dynamic(true)
	.buildWithDefault(Arrays.asList(
	WildcardMatcher.valueOf("(?-i)org.infinispan*"),
	WildcardMatcher.valueOf("(?-i)org.apache.xerces*"),
	WildcardMatcher.valueOf("(?-i)org.jboss.as.*"),
	WildcardMatcher.valueOf("(?-i)io.undertow.core*"),
	WildcardMatcher.valueOf("(?-i)org.eclipse.jdt.ecj*"),
	WildcardMatcher.valueOf("(?-i)org.wildfly.extension.*"),
	WildcardMatcher.valueOf("(?-i)org.wildfly.security*")
	));

by adding WildcardMatcher.caseSensitiveMatcher("*$Proxy") and WildcardMatcher.caseSensitiveMatcher("*$view")

[eyalkoren]

I meant- why are they captured in the test?

[felixbarny]

In a real-world scenario, the transaction would be created by the servlet instrumentation. The JAX-RS instrumentation does not create transactions, it only sets the name. In this test, the transaction is manually created by the private doRequest method.

WDYT about moving it to the default classes_excluded_from_instrumentation?

[eyalkoren]

Ahh, missed the manual transaction creation.

I am not sure about moving to classes_excluded_from_instrumentation. Here it causes a transaction name explosion. Maybe in some scenarios it will capture things that otherwise won't be captured? Like some implementation that creates $Proxy implementations to interface stubs without a resource class in between? If you don't think this is a valid concern, go ahead and move it there.