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34 lines
1.7 KiB
Markdown
34 lines
1.7 KiB
Markdown
What is this?
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=============
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This is a javaagent that may be used while running applications using quasar. It hooks into quasar to track what
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methods are scanned, instrumented and used at runtime, and generates an exclude pattern that may be passed in to quasar
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to stop it from scanning classes unnecessarily.
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Arguments
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===
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`expand`, `alwaysExcluded` and `truncate` tweak the output exclude pattern. `expand` is a list of packages to always expand (for example
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instead of generating `com.*` generate `com.google.*,com.typesafe.*` etc.), `alwaysExcluded` is a list of packages under
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which all classes are considered excluded irregardless of instrumentation, `truncate` is a list of packages that should
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not be included in the exclude pattern. Truncating `net.corda` means nothing should be excluded from instrumentation in
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Corda.
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How to generate an exclude pattern for Corda
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====
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In order to generate a good exclude pattern we need to exercise the Corda code so that most classes get loaded and
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inspected by quasar and quasar-hook. For this we can run tests using the 'Quasar exclude pattern extraction (...)'
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intellij run configuration, which includes the hook. In addition we should run the tool on a bare corda.jar, as some
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additional classes are used when the jar is invoked directly. To do this we'll use a node in samples:
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```
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./gradlew experimental:quasar-hook:jar
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./gradlew samples:irs-demo:deployNodes
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cd samples/irs-demo/build/nodes/NotaryService
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java -javaagent:../../../../../experimental/quasar-hook/build/libs/quasar-hook.jar=expand=com,de,org,co,io;truncate=net.corda;alwaysExcluded=com.opengamma,io.atomix,org.jolokia -jar corda.jar
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```
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Once the node is started just exit the node.
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We can take the union of the two generated exclude patterns to get a final one. |