Spring Boot Gradle plugin >= v2.5.0 outputs both executable fat jar and plain jar, and GAE Gradle plugin uses plain one.

[polyomino24]

This is not a bug, but a feature request.
Spring Boot Gradle plugin in the current version generates both executable fat jar and plain jar in the default settings like
build/libs/aaa-0.0.1.jar
build/libs/aaa-0.0.1-plain.jar
, and when I run ./gradlew appengineShowConfiguration, it shows stage artifact is plain one.

My feature request is that GAE plugin will use fat one automatically without specifying artifact or disabling generating plain one.

environment:
macOS10.15.7
openjdk version "11.0.12" 2021-07-20 LTS
gradle 6.8.3
Spring Boot Gradle plugin 2.5.4
GAE Gradle plugin 2.4.2
GAE: flexible and custom runtime

reference:
https://docs.spring.io/spring-boot/docs/2.5.1/gradle-plugin/reference/htmlsingle/#packaging-executable.and-plain-archives

[elefeint]

@polyomino-24 Just to clarity, does the GAE gradle plugin deploy the correct JAR with appengineDeploy, and only shows the wrong JAR in appengineShowConfiguration?

[polyomino24]

@elefeint
Thanks for reading the issue.
No, when I run appengineDeploy, the files in build/staged-app directory are only plain jar, Dockerfile, and app.yaml.
Actually, my Dockerfile is

FROM openjdk:11-oracle
COPY main-0.0.1.jar main.jar
CMD ["java", "-Duser.timezone=Asia/Tokyo", "-jar", "/main.jar"]%

and when I updated Spring Boot Gradle plugin, I became unable to deploy with appengineDeploy because main-0.0.1.jar(fat jar) was not in the build/stage-app directory.

[elefeint]

Did this work with the earlier versions of Spring Boot plugin?

[polyomino24]

Yes, version 2.4.4 did work.

[chanseokoh]

You can set appengine.stage.artifact to specify a deploy artifact:

appengine.stage.artifact = 'build/libs/demo-0.0.1-SNAPSHOT.jar'

I'm afraid this feature request is a very low priority for us. We accept contributions though.

[polyomino24]

Thanks for your comment!
I know that this workaround works and this request is a low priority for your team, but I think Gradle + Spring boot + Google App Engine is a commonly used combination so I wrote this issue to help someone.
Please close this issue if you want.

[chanseokoh]

Thanks for the feedback. I will leave this open.

[zp-chen-hkmci]

more friendly one:

appengine {
    stage {
        artifact = bootJar.archiveFile.get()
    }
}

[elefeint]

At minimum we should document these workarounds. I've run into this last year and thoroughly forgot.