Unable to Prevent JRE Download in Restricted Environment with Paketo Buildpacks in Spring Boot bootBuildImage Task

[EzzOps]

Issue

Building a Spring Boot image with bootBuildImage in a restricted environment (no internet) fails because Paketo’s bellsoft-liberica buildpack keeps trying to download the JRE from GitHub, ignoring my local file at /work/bellsoft-jre17.0.14+10-linux-amd64.tar.gz. Goal is to use the local JRE offline.

./gradlew bootBuildImage -PpackArgs="--env BP_DEPENDENCY_MIRROR='http://10.43.233.37:8081/repository/Bill/'"

Latest log:

[creator] BellSoft Liberica JRE 17.0.14: Contributing to layer
[creator]   Downloading from https://github.com/bell-sw/Liberica/releases/...
[creator] ERROR: failed to build: exit status 1

---

Trials

1. BP_JAVA_INSTALLATION_URL:

   • export BP_JAVA_INSTALLATION_URL=file:///work/bellsoft-jre17.0.14.tar.gz; ./gradlew bootBuildImage
   • Result: Ignored, still downloads.

2. BP_DEPENDENCY_MIRROR:

   • ./gradlew bootBuildImage -PpackArgs="--env BP_DEPENDENCY_MIRROR='http://10.43.233.37:8081/repository/Bill/'"
   • Result: No effect, still downloads.

---

Questions

• How do I ensure the local JRE is used offline?

[dmikusa]

With the spring boot build tools, you need to set the env variables within your build configuration file.

Gradle example:

tasks.named("bootBuildImage") {
	environment["BP_DEPENDENCY_MIRROR"] = "http://10.43.233.37:8081/repository/Bill/"
}

https://docs.spring.io/spring-boot/gradle-plugin/packaging-oci-image.html#build-image.examples.builder-configuration

That assumes from inside the container, there is network access to the URL in that configuration property and that it can fetch the files needed from there via HTTP. If you get errors fetching the file from that location, please look at how your hosting & exposing that mirror to the container.

Side note. You can also use binding-tool and dependency mapping files. These are also configured through your build tool config file, see here for gradle (it's the bindings property).