Make the use of Mandrel images easier

[zakkak]

Description

Currently Quarkus defaults to using native-image from $GRAALVM_HOME/bin, $JAVA_HOME/bin, or the system's $PATH. If native-image is not available then it falls back to using a container runtime with the ubi-quarkus-native-image container image.

The main benefit of this is that users can simply run:

./mvnw -Pnative package

and create a native executable of their Quarkus application without any local setup. This also makes it easy to ensure that the users are using the correct container image (and the correct version) since it's defined in build-parent/pom.xml

In order for users to use Mandrel they need to do one of the following:

• Download Mandrel, set it up, and make sure native-image can be found either in $GRAALVM_HOME/bin, $JAVA_HOME/bin, or the system's $PATH.
• Use -Dquarkus.native.builder-image=quay.io/quarkus/ubi-quarkus-mandrel:21.0-java11

Now the issue I see with both options is that the user is responsible for figuring out the correct Mandrel version to use.
I believe that Quarkus should offer an option to allow users to state that they would like to build their native executable using Mandrel without the need to worry about the correct version.

e.g.

./mvnw -Pnative `-Dquarkus.native.mandrel=true` package

Implementation ideas

We could possibly introduce yet another property like quarkus.native.mandrel or we could handle something like -Dquarkus.native.builder-image=mandrel and replace mandrel with the ubi-quarkus-mandrel image that is compatible with the Quarkus version being used.

WDYT?

[quarkus-bot]

/cc @galderz

[galderz]

Hmmm, I think I'd leave quarkus.native.builder-image as is, a property that points to a builder image, but I'd give it a default based on the Quarkus version. Instead, I would add something like quarkus.native.provider that takes an enum of graalvm, mandrel or whichever option we might have in the future (e.g. leyden?). Then, to build with mandrel, you'd do:

./mvnw -Pnative package -Dquarkus.native.provider=mandrel

quarkus.native.builder-image would still allow you to tweak the builder image in use, say if you're testing a locally built one, or a newer or older version.

[zakkak]

Although I like how this separates the actual image from the distribution/provider I am afraid it might make things unnecessarily complicated. E.g. , users might think they need to pass -Dquarkus.native.provider=mandrel with -Dquarkus.native.builder-image=quay.io/quarkus/ubi-quarkus-mandrel:21.0-java11 while they shouldn't have to.

I think I like more the option of making quarkus.native.builder-image accept either a value from an enum of graalvm, mandrel or a container image. In that case the default value of quarkus.native.builder-image should become graalvm or mandrel. The only downside I see with this option is that we "reserve" graalvm and mandrel (and whatever might come in the future) making the use of images named like this a bit harder, but I don't expect this to be an issue.

@gsmet @geoand WDYT?

[geoand]

That sounds like an interesting idea, I like it!

[galderz]

I think that's a fair suggestion. I would suggest validating the contents of the property early on so that any mistakes are clearly reported. So, it's either one of the 2 (currently) reserved words, or a URL.