How to set dependency-mapping binding in gradle bootBuildImage (Spring-boot 2.7.1, native)

Question

I am using spring-boot 2.7.1 with native configuration as the guide follows in the link. Spring native official doc

My problem is that when running bootBuildImage, the buildpack ["gcr.io/paketo-buildpacks/java-native-image:7.19.0"] is trying to download external dependency paketo-buildpacks/bellsoft-liberica from https://download.bell-sw.com/vm/22.3.0/bellsoft-liberica-vm-core-openjdk17.0.5+8-22.3.0+2-linux-amd64.tar.gz which is not allowed by company firewall.

I then researched that you can configure dependeny-mapping bindings towards these dependencies within required buildpack, at-least using this pack cli guide.

But when using purely pack-cli the gradle bootBuildImage gets a bit irrelevant and then I have to use some external tool to fix the native docker container and image. And I would like to only use the bootBuildImage to map these dependency-bindings.

I found this binding function within Gradle bootBuildImage docs. but I am not sure what string it expects, if the path should be similar to pack-cli config or not, can't find any relevant info.

The provided image show the bootBuildImage config

bootBuildImage {
    builder = 'docker.io/paketobuildpacks/builder:tiny'
    runImage = 'docker.io/paketobuildpacks/run:tiny-cnb'
    buildpacks = ['gcr.io/paketo-buildpacks/java-native-image']
    binding("bindnings/bellsoft-jre-config:/platform/bindings/bellsoft-jre-config")
    environment = [
            "BP_NATIVE_IMAGE" : "true",
    ]
}

The dependency-mapping config contains 2 files:

The type file contains:

echo "dependency-mapping" >> type

The sha256 (bellsoft-liberica) file 3dea0f7a9312c738d22b5e399b6ce9abe13b45b2bc2c04346beb941a94e8a932 contains:

'echo "https://download.bell-sw.com/vm/22.3.0/bellsoft-liberica-vm-core-openjdk17.0.5+8-22.3.0+2-linux-amd64.tar.gz" >> 3dea0f7a9312c738d22b5e399b6ce9abe13b45b2bc2c04346beb941a94e8a932'

And yes I'm aware that this is the exact same url, but this is just to test that the binding config is correctly setup. Because if ok it should fail on untrusted certificate when downloading instead.

Currently the build fails with:

Caused by: org.springframework.boot.buildpack.platform.docker.transport.DockerEngineException: Docker API call to 'localhost/v1.24/containers/create' failed with status code 400 "Bad Request"
    at org.springframework.boot.buildpack.platform.docker.transport.HttpClientTransport.execute(HttpClientTransport.java:156)
    at org.springframework.boot.buildpack.platform.docker.transport.HttpClientTransport.execute(HttpClientTransport.java:136)
    at org.springframework.boot.buildpack.platform.docker.transport.HttpClientTransport.post(HttpClientTransport.java:108)
    at org.springframework.boot.buildpack.platform.docker.DockerApi$ContainerApi.createContainer(DockerApi.java:340)
    at org.springframework.boot.buildpack.platform.docker.DockerApi$ContainerApi.create(DockerApi.java:331)
    at org.springframework.boot.buildpack.platform.build.Lifecycle.createContainer(Lifecycle.java:237)
    at org.springframework.boot.buildpack.platform.build.Lifecycle.run(Lifecycle.java:217)
    at org.springframework.boot.buildpack.platform.build.Lifecycle.execute(Lifecycle.java:151)
    at org.springframework.boot.buildpack.platform.build.Builder.executeLifecycle(Builder.java:157)
    at org.springframework.boot.buildpack.platform.build.Builder.build(Builder.java:115)
    at org.springframework.boot.gradle.tasks.bundling.BootBuildImage.buildImage(BootBuildImage.java:521)

Which i assume is caused by invalid binding config. But I can't find what is should be.

Paketo configuration (binding)

Answer 1

Dependency mapping bindings can be tricky. There are a number of things that have to be just right, or the buildpacks won't pick up the binding and won't map dependencies.

While there are talks of how we can change this in buildpacks to make swapping out dependencies easier, the short-term solution is to use binding-tool.

You can run bt dm -b paketo-buildpacks/bellsoft-liberica and it will go download the dependencies from the specified buildpack and generate the binding files for you.

It will by default download dependencies and write the bindings to $PWD/bindings but you can change that. For example, I like to put my dependencies in my home directory so I can share them across apps. Ex: SERVICE_BINDING_ROOT=~/.bt/bindings bt dm ..., or export SERVICE_BINDING_ROOT=~/.bt/bindings (or whatever command you run to set an env variable in your shell).

Once you have the bindings created, you just need to point your app to them. How you set the property differs between Maven & Gradle, but the value of the property is the same. It should be <local-path>:<container-path>.

The local path should be the full or relative path to where you created the bindings with bt dm. The container path should almost always be /platform/bindings. This maps your full set of bindings locally to the full set of bindings that the buildpacks will consume. In other words, put all of your bindings into the same directory locally, map that to /platform/bindings and the buildpacks will see everything.

For example with Gradle: binding("bindings/:/platform/bindings").

You can adjust the container path by setting SERVICE_BINDING_ROOT in the container as well, but it doesn't offer a lot of advantage.

You can also set multiple entries for bindings, so long as the paths are unique. So you could set binding("/home/user/.bt/bindings/foo:/platform/bindings/foo") and also binding("bindings/bar:/platform/bindings/bar"). That would let you take bindings from two different locations locally and map them into the /platform/bindings directory so both would be visible to buildpacks. This gives you more fine-grained control but as you can see becomes pretty verbose.

Details on configuring Maven and configuring Gradle for buildpacks can be found at those links.