Issue 360 debug ipv4 cat

[anthonydahanne]

Another to fix #360, without opening a port

Summary

Use Cases

Checklist

• [X] I have viewed, signed, and submitted the Contributor License Agreement.
• [X] I have linked issue(s) that this PR should close using keywords or the Github UI (See docs)
• [X] I have added an integration test, if necessary.
• [X] I have reviewed the styleguide for guidance on my code quality.
• [X] I'm happy with the commit history on this PR (I have rebased/squashed as needed).

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• :white_check_mark: login: anthonydahanne / name: Anthony Dahanne (2e4cf6fd51fa3521e9e4ab1a5146e7e430119ef2)

[anthonydahanne]

To verify it worked fine, I've been using a logalot version of this branch, that you can see for yourself in https://github.com/anthonydahanne/libjvm/releases/tag/v1.44.360-debugcat3

Create a test (composite) buildpack

Then, I built a bellsoft-liberica out of it, but to do so without publishing a new libjvm, I also relocated all modules to github.com/anthonydahanne/libjvm v1.44.360-debugcat3 . The steps involved some:

• version = "9.13.2-debugcat3"
• GOOS="linux" go build -ldflags='-s -w' -o bin/helper github.com/anthonydahanne/libjvm/cmd/helper
• GOARCH="amd64" scripts/build.sh
• pack buildpack package pif/bellsoft-liberica:9.13.2-debugcat3 --publish

Then I built a java-lite composite buildpack, the steps involved some:

• version = "9.14.2-debugcat3"
• version = "9.13.2-debugcat3"

  [[dependencies]]
  uri = "docker://gcr.io/pif/bellsoft-liberica:9.13.2-debugcat3"

• cp package.toml ~/workspaces/tmp/
• printf '[buildpack]\nuri = "%s"\n\n[platform]\nos = "%s"\n' "${~/workspaces/tmp/}"/buildpack "linux" >> "${/workspaces/tmp/}"/package.toml
• create-package --source . --destination ~/workspaces/tmp/buildpack --version 9.14.2-debugcat3
• pack buildpack package pif/java-lite:9.14.2-debugcat3 --config /Users/anthonyd2/workspaces/tmp/package.toml --publish

Test it out

First, I tested it with the samples/java/maven on a machine with IPv6, to check it was not switching to IPv4

• pack build mavenapp --env BP_JVM_VERSION=17 -B paketobuildpacks/builder-jammy-buildpackless-tiny -b pif/java-lite:9.14.2-debugcat3
• docker run --env BPL_DEBUG_ENABLED=true -it mavenapp

  Setting Active Processor Count to 8
  cool, setting it to default, /sys/module/ipv6/parameters/disable
  entering
  value is 0
  enabled, exting true
  Debugging enabled on address *:8000

Then, I tested it on a machine not providing IPv6 support (via tanzu / kpack though) and I got this startup:

Setting Active Processor Count to 4
cool, setting it to default, /sys/module/ipv6/parameters/disable
entering
value is 1
not enabled, exting false
IPv6 does not seem to be enabled in the container, configuring debug agent with 0.0.0.0
Debugging enabled on address 0.0.0.0:9005

That's about it!

Ready for review!