Gradle Shadow Plugin.jar 未在 Docker 容器上运行，没有主清单属性

Question

I built a fat jar using the Gradle Shadow Plugin like so:

tasks {
    "build" {
        dependsOn(shadowJar)
    }
    shadowJar {
        mergeServiceFiles {
            var path = "META-INF/"
        }
        manifest.inheritFrom(jar.get().manifest)
        manifest.attributes["Main-Class"] = "some.main.class.Main"
        manifest.attributes["Implementation-Version"] = version
    }
}

This works with no problem when I do gradle build and then java -jar fat_jar_name.jar , I have tested in MacOS , Windows and Ubuntu (WSL) . The same command works exactly the same on all those platforms, even if the.jar was not locally built, but for some reason it is not working in Docker with eclipse-temurin .

I am trying to run a.jar file within Docker using:

FROM eclipse-temurin:17
ARG JAR_FILE=build/libs/*jar
COPY ${JAR_FILE} fat_jar_name-all.jar

ENTRYPOINT java -jar fat_jar_name.jar

I build the image using docker image build -t image_name. , and then I am trying to run it using docker run -d -p 8080:8080 image_name .

I get this error when running:

no main manifest attribute, in fat_jar_name-all.jar

I found that this issue is related to not having a META-INF\MANIFEST.MF file in the exported .jar . However, the fat_jar_name.jar does contain a manifest file with these contents:

Manifest-Version: 1.0
Main-Class: some.main.class.Main
Implementation-Version: 3.9.1-SNAPSHOT

Is there something I'm missing at the Docker , Gradle or Shadow Plugin level to make this work?

I found this resource for the Shadow Plugin about configuring the manifest, but it makes no mention of a main manifest attribute .

Answer 1

I found that the COPY command I was using was broken. I used this one instead:

FROM eclipse-temurin:17
COPY build/libs/fat_jar_name-all.jar /
ENTRYPOINT java -jar fat_jar_name-all.jar