Separate layer for snapshot dependencies in quarkus-container-image-jib

[kekbur]

Description
I have a multi-module Maven project where a Quarkus application declares snapshot dependencies to the other modules. Currently quarkus-container-image-jib lumps all jar files in target/lib together into a single Docker image layer, including the snapshot jars of my dependent modules. This makes the Docker images much less efficient than what they could be because there is 50 MB of never changing content and a few hundred kilobytes of always changing content in one layer.

As a workaround I attempted to make my snapshot builds reproducible using reproducible-build-maven-plugin, but this effort failed because jandex-maven-plugin does not generate reproducible results. Somebody wanted to make jandex builds reproducible, but that effort seems to be on hold.

Implementation ideas
quarkus-container-image-jib should generate a separate layer for jars that have SNAPSHOT in their name. The layer would be directly on top of the dependent libraries layer.

References

Adjacent discussion at #9818.

[ghost]

/cc @geoand

[geoand]

This is a really good idea

[geoand]

@aloubyansky is there a way we can know from the AppModel whether or not a runtime dependency is part of the "project" or not? getLocalProjectArtifacts maybe?

[gsmet]

Shouldn't we put all snapshot dependencies in a separate layer, whether they're part of the project or not? They are moving targets anyway.

[geoand]

That's a good idea as well - and part of a second enhancement

[gsmet]

Oh, I thought it would be easier given you asked how to differentiate them :).

[geoand]

Now that I started to implement it, you are right :)

[geoand]

@gsmet I followed your advice and opened #14362

[aloubyansky]

@aloubyansky is there a way we can know from the AppModel whether or not a runtime dependency is part of the "project" or not? getLocalProjectArtifacts maybe?

yes

[kekbur]

Well, that was fast. Thanks guys.

[geoand]

Keep in mind that for the time being what you requested will only work when the version of your project (and therefore the dependencies) use the SNAPSHOT in their version.

This restriction might be lifted in later revisions of the code