解压Dockerfile中的Spring Boot fat jar时出错

Question

我正在为我的Spring Boot应用程序构建一个Docker容器。为了优化缓存，我想把Spring Boot生成的fat jar分解成几个层。我能够通过在Gradle文件和Dockerfile之间拆分解包过程来实现这一点，但我更喜欢在Dockerfile中处理所有事情。我目前的方法: Gradle代码片段：

task explodeJar {
   dependsOn(jar)
   doLast {
      project.delete "$projectDir/build/dependencies"
      project.mkdir "$projectDir/build/dependencies"
      exec {
        workingDir "$projectDir/build/dependencies"     
        commandLine "jar", "-xf", "../libs/${project.name}-${project.version}.jar"
      } 
   }
}   

Dockerfile：

ARG DEPENDENCY=/build/dependencies
COPY ${DEPENDENCY}/BOOT-INF/lib /app/lib
COPY ${DEPENDENCY}/META-INF /app/META-INF
COPY ${DEPENDENCY}/BOOT-INF/classes /app
ENTRYPOINT ["java","-cp","app:app/lib/*","mypackage.MyApp"]

当我运行./gradlew explodeJar命令，然后运行docker build -t myapp-spring:0.0.1-SNAPSHOT --build-arg BUILD_VERSION=0.0.1-SNAPSHOT .时，容器构建没有任何问题，但是当我试图将jar解压缩文件移到Dockerfile中时

ARG BUILD_VERSION

ARG JAR_FILE=build/libs/payouts-spring-${BUILD_VERSION}.jar
ARG DEPENDENCY=/build/dependencies
CMD unzip -d ${DEPENDENCY} ${JAR_FILE}

COPY ${DEPENDENCY}/BOOT-INF/lib /app/lib
COPY ${DEPENDENCY}/META-INF /app/META-INF
COPY ${DEPENDENCY}/BOOT-INF/classes /app
ENTRYPOINT ["java","-cp","app:app/lib/*","mypackage.MyApp"]

Docker构建失败，并显示以下错误：

 => CACHED [2/6] RUN yum install -y java-11-amazon-corretto                                                                                                                                                        0.0s
 => CACHED [3/6] RUN yum install -y tar unzip procps                                                                                                                                                               0.0s
 => ERROR [4/6] COPY /build/dependencies/BOOT-INF/lib /app/lib                                                                                                                                                     0.0s
 => ERROR [5/6] COPY /build/dependencies/META-INF /app/META-INF                                                                                                                                                    0.0s
 => ERROR [6/6] COPY /build/dependencies/BOOT-INF/classes /app                                                                                                                                                     0.0s
------
 > [4/6] COPY /build/dependencies/BOOT-INF/lib /app/lib:
------
------
 > [5/6] COPY /build/dependencies/META-INF /app/META-INF:
------
------
 > [6/6] COPY /build/dependencies/BOOT-INF/classes /app:
------
failed to compute cache key: "/build/dependencies/BOOT-INF/classes" not found: not found

Answer 1

您将收到"no no file or directory“错误。尝试从dockerfile和target所在的位置运行以下命令。

mkdir -p target/dependency && (cd target/dependency; jar -xf ../*.jar)

祝你好运！

Answer 2

我通过将jar复制到容器中并解压缩到容器中解决了这个问题：

FROM amazonlinux:2
RUN yum install -y java-11-amazon-corretto
ARG BUILD_VERSION
ENV APP_HOME /apps/services
EXPOSE 8080

# unpack and copy folders
ARG JAR_FILE=build/libs/payouts-spring-${BUILD_VERSION}.jar
ARG JAR_DIR=/build
ARG DOCKER_JAR_FILE=${JAR_DIR}/payouts-spring.jar

COPY ${JAR_FILE}  ${DOCKER_JAR_FILE}
WORKDIR ${JAR_DIR}
RUN  jar -xf ${DOCKER_JAR_FILE}

RUN mkdir -p ${APP_HOME}

RUN cp -R  BOOT-INF/lib ${APP_HOME}
RUN cp -R  META-INF/* ${APP_HOME}/META-INF
RUN cp -R  BOOT-INF/classes/* ${APP_HOME}


WORKDIR /
RUN rm -r ${JAR_DIR}


ENTRYPOINT ["java","-cp","apps/services:apps/services/lib/*", "com.myApp"]

Answer 3

不能直接回答你的问题，但你也可以看看jib。它提供了一个Gradle插件，并遵循Docker分层的最佳实践，自动为您创建一个Docker容器。