<platform> configuration should be configurable with system properties

[chanseokoh]

For example, -Djib.from.platforms=... list of platforms ....

Note that architecture and os are required sub-properties. Need to think about the format. Also consider #2471.

[LeaTaka]

Any progress on this?

I like to decouple the choice of platform from my app.
So for example this would be handy -->
-Djib.from.image=arm32v7/adoptopenjdk:11-jre-hotspot
-Djib.from.platforms.platform.architecture=arm
-Djib.from.platforms.platform.os=linux

[chanseokoh]

If your main goal is to decouple the platform settings, then for now, you can easily parameterize them through Maven properties with default values.

[LeaTaka]

Hey, thanks for your reply!

I use parameterization for most settings, however for the deeply nested platform settings like 'architecture' and 'os', I can't get it to work. In my example below I'll show you what works and what doesn't.

POM settings that work well:

<from>
  <image>arm32v7/adoptopenjdk:11-jre-hotspot</image>
  <platforms>
    <platform>
      <architecture>arm</architecture>
      <os>linux</os>
    </platform>
  </platforms>
</from>

Above settings replaced by parameters in mvn command:
-Djib.from.image=arm32v7/adoptopenjdk:11-jre-hotspot (THIS WORKS)
-Djib.from.platforms.platform.architecture=arm (DOESN'T GET PICKED UP)
-Djib.from.platforms.platform.os=linux (DOESN'T GET PICKED UP)

Maybe I got the explanation in the docs wrong --> (i.e. -Djib.parameterName[.nestedParameter.[...]]=value), any ideas?

[chanseokoh]

@LeaTaka so what I was talking about as a workaround was to use standard Maven features to accomplish the same effect of using the built-in Jib system and Maven properties. For the built-in Jib properties, our code reads system and Maven properties like this, but as you observed, this isn't defined for the <platform> configurations yet. So, what you can do with standard Maven features is like:

<properties>
  <!-- Define Maven properties. These are arbitrary Maven properties, so you can name them however you want. -->
  <jib.platform-arch>amd64</jib.platform-arch> <!-- most likely the default value you want to use -->
  <jib.platform-os>linux</jib.platform-os>
</properties>

...

   <!-- Jib configuration -->
   <from>
     <image>arm32v7/adoptopenjdk:11-jre-hotspot</image>
     <platforms>
       <platform>
         <architecture>${jib.platform-arch}</architecture>
         <os>${jib.platform-os}</os>
       </platform>
     </platforms>
   </from>

Then, when you run Jib, by default the platform will be linux/amd64. If you want to override the Maven properties, you'd do, e.g.,

$ ./mvnw -Djib.platform-arch=arm jib:build

[StringKe]

How to set up multiple platforms?

-Djib.from.platforms[0].os=linux -Djib.from.platforms[0].architecture=amd64 -Djib.from.platforms[1].os=linux -Djib.from.platforms[1].architecture=arm64

or

-Djib.from.platforms.os=linux -Djib.from.platforms.architecture=amd64 -Djib.from.platforms.os=linux -Djib.from.platforms.architecture=arm64

[chanseokoh]

@StringKe it's a list property. For example, -Djib.from.platforms=linux/amd64,linux/arm64.