2021年 最新 多阶段构建dockerfile实现java源码编译打jar包并做成镜像
2021年 最新 多阶段构建dockerfile实现java源码编译打jar包并做成镜像
猫头虎
发布于 2024-04-07 17:06:31
发布于 2024-04-07 17:06:31
多阶段构建指在Dockerfile中使用多个FROM语句，每个FROM指令都可以使用不同的基础镜像，并且是一个独立的子构建阶段。使用多阶段构建打包Java应用具有构建安全、构建速度快、镜像文件体积小等优点.
背景信息
镜像构建的通用问题
镜像构建服务使用Dockerfile来帮助用户构建最终镜像，但在具体实践中，存在一些问题： Dockerfile编写有门槛 开发者（尤其是Java）习惯了语言框架的编译便利性，不知道如何使用Dockerfile构建应用镜像。
镜像容易臃肿 构建镜像时，开发者会将项目的编译、测试、打包构建流程编写在一个Dockerfile中。每条Dockerfile指令都会为镜像添加一个新的图层，从而导致镜像层次深，镜像文件体积特别大。
存在源码泄露风险 打包镜像时，源代码容易被打包到镜像中，从而产生源代码泄漏的风险。
多阶段构建优势
针对Java这类的编译型语言，使用Dockerfile多阶段构建，具有以下优势：
保证构建镜像的安全性
当您使用Dockerfile多阶段构建镜像时，需要在第一阶段选择合适的编译时基础镜像，进行代码拷贝、项目依赖下载、编译、测试、打包流程。在第二阶段选择合适的运行时基础镜像，拷贝基础阶段生成的运行时依赖文件。最终构建的镜像将不包含任何源代码信息。
优化镜像的层数和体积
构建的镜像仅包含基础镜像和编译制品，镜像层数少，镜像文件体积小。
提升构建速度
使用构建工具（Docker、Buildkit等），可以并发执行多个构建流程，缩短构建耗时。
使用多阶段构建Dockerfile
以Java Maven项目为例，在Java Maven项目中新建Dockerfile文件，并在Dockerfile文件添加以下内容。 说明 该Dockerfile文件使用了二阶段构建。
第一阶段：
选择Maven基础镜像（Gradle类型也可以选择相应Gradle基础镜像）完成项目编译，拷贝源代码到基础镜像并运行RUN命令，从而构建Jar包。
第二阶段：
拷贝第一阶段生成的Jar包到OpenJDK镜像中，设置CMD运行命令。
方案一:
通俗易懂篇:
# First stage: complete build environment
FROM maven:3.5.0-jdk-8-alpine AS builder
# add pom.xml and source code
ADD ./pom.xml pom.xml
ADD ./src src/
# package jar
RUN mvn clean package
# Second stage: minimal runtime environment
From openjdk:8-jre-alpine
# copy jar from the first stage
COPY --from=builder target/my-app-1.0-SNAPSHOT.jar my-app-1.0-SNAPSHOT.jar
EXPOSE 8080
CMD ["java", "-jar", "my-app-1.0-SNAPSHOT.jar"]方案二:
对于一个 Java 应用，如果要部署到 Kubernetes，首先需要创建一个容器镜像。这其实由两个步骤组成：
构建 Java 源代码，并打包成 JAR 文件。
把 JAR 文件和 JDK 组合在一起，创建出容器镜像。
在一般的构建过程中，这两个步骤是分开的。第一步由本地机器上的 Maven 或 Gradle 来完成，第二步使用 Docker 命令从 Dockerfile 中创建出镜像，并使用第一步构建出的本地 JAR 文件。
当需要使用某些公开容器镜像注册表（如 Docker Hub 和 Quay.io）提供的持续集成功能时，就不能再分成两个步骤，因为这些注册表只支持构建容器镜像，并没有提供应用构建的支持。
通过使用 Docker 提供的多阶段构建（multi-stage build）功能，我们可以很容易地把这两个步骤合成一个。
对于一个 Spring Boot 应用，下面的 Dockerfile 文件可以完成从源代码到镜像的构建。第一个阶段使用 Maven 镜像作为基础，在把 src 目录和 pom.xml 复制到镜像中之后， 使用 Maven 命令来编译源代码并打包。builder 是这个阶段的名称。在这个阶段完成之后，/build/target 目录中包含了所产生的 JAR 文件。
第二个阶段使用 OpenJDK 11 Alpine 镜像作为基础， COPY 命令把第一个阶段产生的 JAR 文件复制到当前镜像中。–from=builder 参数指定了复制的来源是第一个阶段产生的镜像。
大牛篇;
FROM maven:3.6.3-openjdk-8 AS builder
# AS builder 起别名
RUN mkdir /build
# 创建临时文件
ADD src /build/src
#将 src目录复制到临时目录
ADD pom.xml /build
# 将 pom文件复制到临时目录
RUN cd /build && mvn -B -ntp package
# 打包
FROM adoptopenjdk/openjdk8:alpine-jre
# 获取jre
COPY --from=builder /build/target/ems-0.0.1-SNAPSHOT.jar /ems.jar
#从标记点 拷贝jar包 并改名
CMD ["java", "-jar", "/ems.jar"]
# 声明运行方式当使用 Docker 命令来构建这个 Dockerfile 文件之后，所得到的镜像中只包含 JAR 文件和 JDK。
IDEA文件结构如下:
命令行信息对比:
[root@localhost ~/myems]# docker build -t ems1:1.0 .
Sending build context to Docker daemon 32.77kB
Step 1/8 : FROM maven:3.6.3-openjdk-8 AS builder
---> d1b3f61d61f2
Step 2/8 : RUN mkdir /build
---> Running in 08cadf2db7b4
Removing intermediate container 08cadf2db7b4
---> 836eeb13f7fe
Step 3/8 : ADD src /build/src
---> b5d73ef7ed79
Step 4/8 : ADD pom.xml /build
---> 5e9a5ce77859
Step 5/8 : RUN cd /build && mvn -B -ntp package
---> Running in d92bbcd7ab54
[INFO] Scanning for projects...
[INFO]
[INFO] ---------------------------< com.baizhi:ems >---------------------------
[INFO] Building ems 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.2.0:resources (default-resources) @ ems ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 1 resource
[INFO] Copying 1 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ ems ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 6 source files to /build/target/classes
[INFO]
[INFO] --- maven-resources-plugin:3.2.0:testResources (default-testResources) @ ems ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] skip non existing resourceDirectory /build/src/test/resources
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ ems ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /build/target/test-classes
[INFO]
[INFO] --- maven-surefire-plugin:2.22.2:test (default-test) @ ems ---
[INFO]
[INFO] -------------------------------------------------------
[INFO] T E S T S
[INFO] -------------------------------------------------------
[INFO] Running com.baizhi.EmsApplicationTests
12:11:00.101 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating CacheAwareContextLoaderDelegate from class [org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate]
12:11:00.200 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating BootstrapContext using constructor [public org.springframework.test.context.support.DefaultBootstrapContext(java.lang.Class,org.springframework.test.context.CacheAwareContextLoaderDelegate)]
12:11:02.814 [main] DEBUG org.springframework.test.context.BootstrapUtils - Instantiating TestContextBootstrapper for test class [com.baizhi.EmsApplicationTests] from class [org.springframework.boot.test.context.SpringBootTestContextBootstrapper]
12:11:03.386 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Neither @ContextConfiguration nor @ContextHierarchy found for test class [com.baizhi.EmsApplicationTests], using SpringBootContextLoader
12:11:03.427 [main] DEBUG org.springframework.test.context.support.AbstractContextLoader - Did not detect default resource location for test class [com.baizhi.EmsApplicationTests]: class path resource [com/baizhi/EmsApplicationTests-context.xml] does not exist
12:11:03.428 [main] DEBUG org.springframework.test.context.support.AbstractContextLoader - Did not detect default resource location for test class [com.baizhi.EmsApplicationTests]: class path resource [com/baizhi/EmsApplicationTestsContext.groovy] does not exist
12:11:03.428 [main] INFO org.springframework.test.context.support.AbstractContextLoader - Could not detect default resource locations for test class [com.baizhi.EmsApplicationTests]: no resource found for suffixes {-context.xml, Context.groovy}.
12:11:03.456 [main] INFO org.springframework.test.context.support.AnnotationConfigContextLoaderUtils - Could not detect default configuration classes for test class [com.baizhi.EmsApplicationTests]: EmsApplicationTests does not declare any static, non-private, non-final, nested classes annotated with @Configuration.
12:11:03.870 [main] DEBUG org.springframework.test.context.support.ActiveProfilesUtils - Could not find an 'annotation declaring class' for annotation type [org.springframework.test.context.ActiveProfiles] and class [com.baizhi.EmsApplicationTests]
12:11:07.746 [main] DEBUG org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider - Identified candidate component class: file [/build/target/classes/com/baizhi/EmsApplication.class]
12:11:07.812 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Found @SpringBootConfiguration com.baizhi.EmsApplication for test class com.baizhi.EmsApplicationTests
12:11:11.875 [main] DEBUG org.springframework.boot.test.context.SpringBootTestContextBootstrapper - @TestExecutionListeners is not present for class [com.baizhi.EmsApplicationTests]: using defaults.
12:11:11.876 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Loaded default TestExecutionListener class names from location [META-INF/spring.factories]: [org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener, org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener, org.springframework.test.context.web.ServletTestExecutionListener, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener, org.springframework.test.context.event.ApplicationEventsTestExecutionListener, org.springframework.test.context.support.DependencyInjectionTestExecutionListener, org.springframework.test.context.support.DirtiesContextTestExecutionListener, org.springframework.test.context.transaction.TransactionalTestExecutionListener, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener, org.springframework.test.context.event.EventPublishingTestExecutionListener]
12:11:12.008 [main] INFO org.springframework.boot.test.context.SpringBootTestContextBootstrapper - Using TestExecutionListeners: [org.springframework.test.context.web.ServletTestExecutionListener@29215f06, org.springframework.test.context.support.DirtiesContextBeforeModesTestExecutionListener@59505b48, org.springframework.test.context.event.ApplicationEventsTestExecutionListener@4efac082, org.springframework.boot.test.mock.mockito.MockitoTestExecutionListener@6bd61f98, org.springframework.boot.test.autoconfigure.SpringBootDependencyInjectionTestExecutionListener@48aca48b, org.springframework.test.context.support.DirtiesContextTestExecutionListener@13fd2ccd, org.springframework.test.context.transaction.TransactionalTestExecutionListener@b9b00e0, org.springframework.test.context.jdbc.SqlScriptsTestExecutionListener@506ae4d4, org.springframework.test.context.event.EventPublishingTestExecutionListener@7d4f9aae, org.springframework.boot.test.mock.mockito.ResetMocksTestExecutionListener@72e5a8e, org.springframework.boot.test.autoconfigure.restdocs.RestDocsTestExecutionListener@54e1c68b, org.springframework.boot.test.autoconfigure.web.client.MockRestServiceServerResetTestExecutionListener@53aac487, org.springframework.boot.test.autoconfigure.web.servlet.MockMvcPrintOnlyOnFailureTestExecutionListener@52b1beb6, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverTestExecutionListener@273e7444, org.springframework.boot.test.autoconfigure.webservices.client.MockWebServiceServerTestExecutionListener@7db12bb6]
12:11:12.022 [main] DEBUG org.springframework.test.context.support.AbstractDirtiesContextTestExecutionListener - Before test class: context [DefaultTestContext@5d534f5d testClass = EmsApplicationTests, testInstance = [null], testMethod = [null], testException = [null], mergedContextConfiguration = [WebMergedContextConfiguration@2e3967ea testClass = EmsApplicationTests, locations = '{}', classes = '{class com.baizhi.EmsApplication}', contextInitializerClasses = '[]', activeProfiles = '{}', propertySourceLocations = '{}', propertySourceProperties = '{org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true}', contextCustomizers = set[org.springframework.boot.test.context.filter.ExcludeFilterContextCustomizer@670002, org.springframework.boot.test.json.DuplicateJsonObjectContextCustomizerFactory$DuplicateJsonObjectContextCustomizer@56528192, org.springframework.boot.test.mock.mockito.MockitoContextCustomizer@0, org.springframework.boot.test.web.client.TestRestTemplateContextCustomizer@460d0a57, org.springframework.boot.test.autoconfigure.actuate.metrics.MetricsExportContextCustomizerFactory$DisableMetricExportContextCustomizer@6af93788, org.springframework.boot.test.autoconfigure.properties.PropertyMappingContextCustomizer@0, org.springframework.boot.test.autoconfigure.web.servlet.WebDriverContextCustomizerFactory$Customizer@4a22f9e2, org.springframework.boot.test.context.SpringBootTestArgs@1, org.springframework.boot.test.context.SpringBootTestWebEnvironment@21bcffb5], resourceBasePath = 'src/main/webapp', contextLoader = 'org.springframework.boot.test.context.SpringBootContextLoader', parent = [null]], attributes = map['org.springframework.test.context.web.ServletTestExecutionListener.activateListener' -> true]], class annotated with @DirtiesContext [false] with mode [null].
12:11:12.467 [main] DEBUG org.springframework.test.context.support.TestPropertySourceUtils - Adding inlined properties to environment: {spring.jmx.enabled=false, org.springframework.boot.test.context.SpringBootTestContextBootstrapper=true}
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.5.2)
2021-06-29 12:12:10.365 INFO 69 --- [ main] com.baizhi.EmsApplicationTests : Starting EmsApplicationTests using Java 1.8.0_282 on d92bbcd7ab54 with PID 69 (started by root in /build)
2021-06-29 12:12:10.368 INFO 69 --- [ main] com.baizhi.EmsApplicationTests : No active profile set, falling back to default profiles: default
2021-06-29 12:18:11.149 INFO 69 --- [ main] com.baizhi.EmsApplicationTests : Started EmsApplicationTests in 418.516 seconds (JVM running for 494.655)
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 514.628 s - in com.baizhi.EmsApplicationTests
2021-06-29 12:19:24.357 INFO 69 --- [ionShutdownHook] com.alibaba.druid.pool.DruidDataSource : {dataSource-0} closing ...
[INFO]
[INFO] Results:
[INFO]
[INFO] Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
[INFO]
[INFO]
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ ems ---
[INFO] Building jar: /build/target/ems-0.0.1-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:2.5.2:repackage (repackage) @ ems ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 19:22 min
[INFO] Finished at: 2021-06-29T12:20:33Z
[INFO] ------------------------------------------------------------------------
Removing intermediate container d92bbcd7ab54
---> e19081a12cd6
Step 6/8 : FROM adoptopenjdk/openjdk8:alpine-jre
alpine-jre: Pulling from adoptopenjdk/openjdk8
540db60ca938: Pull complete
9fc18144b37f: Pull complete
cc610e703026: Pull complete
Digest: sha256:4e7f3fc23cfd6e9751a1465fc4daa2073a3987c72b178ba467b41f3971751205
Status: Downloaded newer image for adoptopenjdk/openjdk8:alpine-jre
---> 32011de768b3
Step 7/8 : COPY --from=builder /build/target/ems-0.0.1-SNAPSHOT.jar /ems.jar
--->32011de768b3
Step 8/8 : CMD ["java", "-jar", "/ems.jar"]
---> Running in cc75371d3a8f
Removing intermediate container cc75371d3a8f
---> 32011de768b3
Successfully built 32011de768b3
Successfully tagged ems:1.0最终效果:
[root@localhost ~/myems]# docker build -t ems:2.0 .
Sending build context to Docker daemon 32.77kB
Step 1/8 : FROM maven:3.6.3-openjdk-8 AS builder
---> d1b3f61d61f2
Step 2/8 : RUN mkdir /build
---> Using cache
---> 836eeb13f7fe
Step 3/8 : ADD src /build/src
---> Using cache
---> b5d73ef7ed79
Step 4/8 : ADD pom.xml /build
---> Using cache
---> 5e9a5ce77859
Step 5/8 : RUN cd /build && mvn -B -ntp package
---> Using cache
---> e19081a12cd6
Step 6/8 : FROM adoptopenjdk/openjdk8:alpine-jre
---> 32011de768b3
Step 7/8 : COPY --from=builder /build/target/ems-0.0.1-SNAPSHOT.jar /ems.jar
---> 84666655f883
Step 8/8 : CMD ["java", "-jar", "/ems.jar"]
---> Running in cc75371d3a8f
Removing intermediate container cc75371d3a8f
---> 554142c1b512
Successfully built 554142c1b512
Successfully tagged ems:2.0最终镜像制作成功
目录结构~
如果大家觉得还不错，点赞，收藏，分享，一键三连支持我一下~
本文参与 腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。
原始发表：2023-08-13，如有侵权请联系 cloudcommunity@tencent.com 删除
评论
登录后参与评论
推荐阅读
目录
相关产品与服务
容器服务
腾讯云容器服务（Tencent Kubernetes Engine, TKE）基于原生 kubernetes 提供以容器为核心的、高度可扩展的高性能容器管理服务，覆盖 Serverless、边缘计算、分布式云等多种业务部署场景，业内首创单个集群兼容多种计算节点的容器资源管理模式。同时产品作为云原生 Finops 领先布道者，主导开源项目Crane，全面助力客户实现资源优化、成本控制。