Adds Native Image Support #842

[driverpt]

GraalVM Support

[brenuart]

Oh nice - thank you.
@driverpt could you please tell me a bit more about how you built this reflect-config.json file? How can we maintain it and make sure it is always accurate?

[codecov]

Codecov Report

Merging #901 (86f2f70) into main (887cf61) will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##               main     #901   +/-   ##
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  Coverage     71.52%   71.52%           
  Complexity     1345     1345           
=========================================
  Files           173      173           
  Lines          4984     4984           
  Branches        518      518           
=========================================
  Hits           3565     3565           
  Misses         1167     1167           
  Partials        252      252           

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[driverpt]

Hello @brenuart ,

I used @msailes Gist to generate a reflect-config.json: https://gist.github.com/msailes/e2e61bdb81d2666d35079be6b5e1cf14

I recommend that this is properly tested and checked if i did not miss anything.

So far i was able to get this working with Micronaut + GraalVM

[DmitryKubahov]

@brenuart @driverpt Thank you all, but do you have any update on it? Would be really awesome to have it.

[philsttr]

For anyone following this PR,... at present, we (the maintainers of logstash-logback-encoder) don't know how to generate, maintain, or test this file, so we cannot accept this PR as-is.

Note the link to the gist mentioned in an earlier comment no longer works.

If the PR were to be enhanced with an automated way to keep the file up-to-date (perhaps as part of the build process) and tests, then we would be more willing to accept it.

[driverpt]

You could use annotations in the code. But that would imply importing libraries and annotating classes

[philsttr]

What annotations? what libraries? What needs to be annotated? How do we test it with automation? Keep in mind I've never used GraalVM before, so explain it to me like a noob ;)

[LeadingMoominExpert]

I can't say for sure what script the original commenter used since the gist link is broken, but graalvm jdk provides an agent for automatically generating the reflection config as well as config files for JNI, proxy objects and class path resources.

https://www.graalvm.org/22.0/reference-manual/native-image/Agent/

Essentially you build a fat jar from your application and run it with the graalvm jdk using the tracing agent

java -agentlib:native-image-agent=config-output-dir=generated-configs -jar app.jar

and the specified generated-configs directory should contain the necessary configuration files. I'm not too familiar with the code in this repository so I don't know how this would actually work, since I cannot find a main manifest and the build jar won't actually run.

The annotation approach is what some frameworks e.g. quarkus and helidon are using to provide ways to annotate the classes that are using reflection.