本文演示瞭如何用 Docker、Gradle 來構建、運行、發佈來一個 Spring Boot 應用。php
Docker 是一個 Linux 容器管理工具包,具有「社交」方面,容許用戶發佈容器的 image (鏡像),並使用別人發佈的 image。Docker image 是用於運行容器化進程的方案,在本文中,咱們將構建一個簡單的 Spring Boot 應用程序。html
有關 Docker 的詳細介紹,能夠移步至 《簡述 Docker》java
項目的目錄結構因符合 Gradle 的約定。nginx
在 *nix 系統下執行 mkdir -p src/main/java/docker_spring_boot
,生產以下結構 :git
└── src └── main └── java └── com └── waylau └── docker_spring_boot
build.gradlegithub
buildscript { repositories { mavenCentral() } dependencies { classpath('org.springframework.boot:spring-boot-gradle-plugin:1.3.3.RELEASE') // tag::build[] classpath('se.transmode.gradle:gradle-docker:1.2') // end::build[] } } apply plugin: 'java' apply plugin: 'eclipse' apply plugin: 'idea' apply plugin: 'spring-boot' // tag::plugin[] apply plugin: 'docker' // end::plugin[] // This is used as the docker image prefix (org) group = 'gregturn' jar { baseName = 'docker-spring-boot-gradle' version = '1.0.0' } // tag::task[] task buildDocker(type: Docker, dependsOn: build) { push = true applicationName = jar.baseName dockerfile = file('src/main/docker/Dockerfile') doFirst { copy { from jar into stageDir } } } // end::task[] repositories { mavenCentral() } sourceCompatibility = 1.8 targetCompatibility = 1.8 dependencies { compile("org.springframework.boot:spring-boot-starter-web") testCompile("org.springframework.boot:spring-boot-starter-test") } task wrapper(type: Wrapper) { gradleVersion = '2.3' }
Spring Boot gradle plugin 提供了不少方便的功能:web
編寫一個簡單的 Spring Boot 應用 :spring
src/main/java/com/waylau/docker_spring_boot/Application.java
:sql
package com.waylau.docker_spring_boot; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; /** * 主應用入口 * @author <a href="http://waylau.com">waylau.com</a> * @date 2016年3月19日 */ @SpringBootApplication @RestController public class Application { @RequestMapping("/") public String home() { return "Hello Docker World." + "<br />Welcome to <a href='http://waylau.com'>waylau.com</a></li>"; } public static void main(String[] args) { SpringApplication.run(Application.class, args); } }
解釋下上面的代碼:docker
@SpringBootApplication
@RestController
標識,可用 Spring MVC 來處理 Web 請求。@RequestMapping
將 /
映射到 home()
,並將"Hello Docker World" 文本做爲響應。main()
方法使用 Spring Boot 的 SpringApplication.run()
方法來啓動應用。編譯:
gradle build
運行:
java -jar build/libs/docker-spring-boot-gradle-1.0.0.jar
若是程序正確運行,瀏覽器訪問 http://localhost:8080/,能夠看到頁面 「Hello Docker World.」 字樣。
Docker 使用 Dockerfile 文件格式來指定 image 層,
建立文件 src/main/docker/Dockerfile
:
FROM frolvlad/alpine-oraclejdk8:slim VOLUME /tmp ADD docker-spring-boot-gradle-1.0.0.jar app.jar ENTRYPOINT ["java","-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
解釋下這個配置文件:
VOLUME
指定了臨時文件目錄爲/tmp
。其效果是在主機 /var/lib/docker
目錄下建立了一個臨時文件,並連接到容器的/tmp
。改步驟是可選的,若是涉及到文件系統的應用就頗有必要了。/tmp
目錄用來持久化到 Docker 數據文件夾,由於 Spring Boot 使用的內嵌 Tomcat 容器默認使用/tmp
做爲工做目錄ENTRYPOINT
執行項目 app.jar。爲了縮短 Tomcat 啓動時間,添加一個系統屬性指向 "/dev/urandom" 做爲 Entropy Source執行構建成爲 docker image:
gradle build buildDocker
運行 Docker Image
docker run -p 8080:8080 -t waylau/docker-spring-boot-gradle
[root@waylau spring-boot]# docker run -p 8080:8080 -t waylau/docker-spring-boot-gradle . ____ _ __ _ _ /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \ ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \ \\/ ___)| |_)| | | | | || (_| | ) ) ) ) ' |____| .__|_| |_|_| |_\__, | / / / / =========|_|==============|___/=/_/_/_/ :: Spring Boot :: (v1.3.3.RELEASE) 2016-03-20 08:45:51.276 INFO 1 --- [ main] c.waylau.docker_spring_boot.Application : Starting Application v1.0.0 on 048fb623038f with PID 1 (/app.jar started by root in /) 2016-03-20 08:45:51.289 INFO 1 --- [ main] c.waylau.docker_spring_boot.Application : No active profile set, falling back to default profiles: default 2016-03-20 08:45:51.722 INFO 1 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@669af5fc: startup date [Sun Mar 20 08:45:51 GMT 2016]; root of context hierarchy 2016-03-20 08:45:54.874 INFO 1 --- [ main] o.s.b.f.s.DefaultListableBeanFactory : Overriding bean definition for bean 'beanNameViewResolver' with a different definition: replacing [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/ErrorMvcAutoConfiguration$WhitelabelErrorViewConfiguration.class]] with [Root bean: class [null]; scope=; abstract=false; lazyInit=false; autowireMode=3; dependencyCheck=0; autowireCandidate=true; primary=false; factoryBeanName=org.springframework.boot.autoconfigure.web.WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter; factoryMethodName=beanNameViewResolver; initMethodName=null; destroyMethodName=(inferred); defined in class path resource [org/springframework/boot/autoconfigure/web/WebMvcAutoConfiguration$WebMvcAutoConfigurationAdapter.class]] 2016-03-20 08:45:57.893 INFO 1 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http) 2016-03-20 08:45:57.982 INFO 1 --- [ main] o.apache.catalina.core.StandardService : Starting service Tomcat 2016-03-20 08:45:57.984 INFO 1 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.0.32 2016-03-20 08:45:58.473 INFO 1 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext 2016-03-20 08:45:58.473 INFO 1 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 6877 ms 2016-03-20 08:45:59.672 INFO 1 --- [ost-startStop-1] o.s.b.c.e.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/] 2016-03-20 08:45:59.695 INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*] 2016-03-20 08:45:59.701 INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*] 2016-03-20 08:45:59.703 INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*] 2016-03-20 08:45:59.703 INFO 1 --- [ost-startStop-1] o.s.b.c.embedded.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*] 2016-03-20 08:46:00.862 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@669af5fc: startup date [Sun Mar 20 08:45:51 GMT 2016]; root of context hierarchy 2016-03-20 08:46:01.166 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto public java.lang.String com.waylau.docker_spring_boot.Application.home() 2016-03-20 08:46:01.189 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) 2016-03-20 08:46:01.190 INFO 1 --- [ main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest) 2016-03-20 08:46:01.302 INFO 1 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2016-03-20 08:46:01.302 INFO 1 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2016-03-20 08:46:01.438 INFO 1 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler] 2016-03-20 08:46:01.833 INFO 1 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup 2016-03-20 08:46:02.332 INFO 1 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http) 2016-03-20 08:46:02.343 INFO 1 --- [ main] c.waylau.docker_spring_boot.Application : Started Application in 13.194 seconds (JVM running for 15.828)
若是程序正確運行,瀏覽器訪問 http://localhost:8080/,能夠看到頁面 「Hello Docker World.」 字樣。
首先,你在 Docker Hub 要有註冊帳號,且建立了相應的庫;
其次,docker 推送前,先要登陸,不然報unauthorized: access to the requested resource is not authorized
的錯誤
執行:
docker login
輸出爲:
[root@waylau spring-boot]# docker login Username: waylau Password: Email: waylau521@gmail.com WARNING: login credentials saved in /root/.docker/config.json Login Succeeded
執行推送
docker push waylau/docker-spring-boot-gradle
[root@waylau spring-boot]# docker push waylau/docker-spring-boot-gradle The push refers to a repository [docker.io/waylau/docker-spring-boot-gradle] 751d29eef02e: Layer already exists 4da3741f39c7: Pushed 5f70bf18a086: Layer already exists 7e4d0cb13643: Layer already exists 8f045733649f: Layer already exists latest: digest: sha256:eb4d5308ba1bb27489d808279e74784bda6761b3574f4298d746abba59b35164 size: 9415
Docker Hub 在國外,有時候拉取 Image 極其緩慢,能夠使用國內的鏡像來實現加速
echo "DOCKER_OPTS=\"--registry-mirror=https://yourlocation.mirror.aliyuncs.com\"" | sudo tee -a /etc/default/docker sudo service docker restart
其中 https://yourlocation.mirror.aliyuncs.com 是您在阿里雲註冊後的專屬加速器地址:
sudo echo 「DOCKER_OPTS=\」\$DOCKER_OPTS –registry-mirror=http://your-id.m.daocloud.io -d\」」 >> /etc/default/docker sudo service docker restart
其中 http://your-id.m.daocloud.io 是您在 DaoCloud 註冊後的專屬加速器地址:
獲取項目源碼, https://github.com/waylau/docker-demos 中的 samples/spring-boot-gradle
獲取項目鏡像, 執行
docker pull waylau/docker-spring-boot-gradle