Build Spring Boot + Docker image in Gradle
TL;DR
--Try to create a Docker image using Gradle --Build SpringBoot in jar format and create a Docker image including java + jar file --Basically, just try according to the Spring Official documentation.
Execution environment construction
environment
The following verification items are implemented on macOS The version of the library etc. used is as follows
- JDK (1.8.0_121)
- Spring Boot (1.5.8)
- Gradle (3.3)
- Docker Version (17.06.2-ce-mac27)
Create a project
Select a project using SPRING INITIALIZR
Try to build with Gradle as Generate a "Gradle Project" and include the web in Dependencies
Unzip the completed demo.zip, build and run the project with gradle
$ unzip demo.jar
$ cd demo
$ ./gradlew build
$ java -jar build/libs/demo-0.0.1-SNAPSHOT.jar
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v1.5.8.RELEASE)
2017-11-10 10:04:09.107 INFO 41308 --- [ main] com.example.demo.DemoApplication : Starting DemoApplication on mac0137.local.furyu.jp with PID 41308 (/Users/moriokanaoki/Downloads/demo/build/libs/demo-0.0.1-SNAPSHOT.jar started by moriokanaoki in /Users/moriokanaoki/Downloads/demo)
2017-11-10 10:04:09.111 INFO 41308 --- [ main] com.example.demo.DemoApplication : No active profile set, falling back to default profiles: default
2017-11-10 10:04:09.193 INFO 41308 --- [ main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@45283ce2: startup date [Fri Nov 10 10:04:09 JST 2017]; root of context hierarchy
2017-11-10 10:04:10.577 INFO 41308 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-11-10 10:04:10.591 INFO 41308 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2017-11-10 10:04:10.592 INFO 41308 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.23
2017-11-10 10:04:10.676 INFO 41308 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2017-11-10 10:04:10.676 INFO 41308 --- [ost-startStop-1] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 1486 ms
2017-11-10 10:04:10.804 INFO 41308 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
2017-11-10 10:04:10.809 INFO 41308 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-11-10 10:04:10.810 INFO 41308 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-11-10 10:04:10.810 INFO 41308 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-11-10 10:04:10.810 INFO 41308 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'requestContextFilter' to: [/*]
2017-11-10 10:04:11.191 INFO 41308 --- [ main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@45283ce2: startup date [Fri Nov 10 10:04:09 JST 2017]; root of context hierarchy
2017-11-10 10:04:11.299 INFO 41308 --- [ 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)
2017-11-10 10:04:11.300 INFO 41308 --- [ 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)
2017-11-10 10:04:11.332 INFO 41308 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-10 10:04:11.333 INFO 41308 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-10 10:04:11.372 INFO 41308 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-11-10 10:04:11.509 INFO 41308 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2017-11-10 10:04:11.578 INFO 41308 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-11-10 10:04:11.583 INFO 41308 --- [ main] com.example.demo.DemoApplication : Started DemoApplication in 2.98 seconds (JVM running for 3.412)
It's working, but it's hard to understand, so I'll try to output about Hello World.
src/main/java/com/example/demo/DemoApplication.java
package com.example.demo;
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;
@SpringBootApplication
@RestController
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
@RequestMapping(value = "/")
String sayHello() {
return "Hello World!";
}
}
If you start demo.jar again and access port 8080 of localhost, you should see" Hello World! ".
Prepare a Dockerfile
In order to create a Docker image that executes the above java -jar, prepare a Dockerfile directly under the project.
Creation of demo.jar etc. is linked with build.gradle change described later
Dockerfile
FROM openjdk:8-jdk-alpine
VOLUME /tmp
ADD target/demo.jar app.jar
ENV JAVA_OPTS=""
ENTRYPOINT exec java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /app.jar
Added gradle-docker plugin
Modify build.gradle to generate Docker image in Gradle.
build.gradle
buildscript {
ext {
springBootVersion = '1.5.8.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
classpath "se.transmode.gradle:gradle-docker:1.2"
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'docker'
group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencies {
compile('org.springframework.boot:spring-boot-starter-web')
testCompile('org.springframework.boot:spring-boot-starter-test')
}
jar {
baseName = 'demo'
archiveName = "${baseName}.jar"
}
task buildDocker(type: Docker, dependsOn: build) {
applicationName = jar.baseName
dockerfile = file('Dockerfile')
doFirst {
copy {
from jar
into "${stageDir}/target"
}
}
}
Build
Let's build it right away.
Don't forget to start Docker on macOS here
$ ./gradlew build buildDocker
Starting a Gradle Daemon, 1 incompatible Daemon could not be reused, use --status for details
:compileJava
:processResources UP-TO-DATE
:classes
:findMainClass
:jar
:bootRepackage
:assemble
:compileTestJava
:processTestResources NO-SOURCE
:testClasses
:test
2017-11-10 22:27:45.286 INFO 43631 --- [ Thread-5] o.s.w.c.s.GenericWebApplicationContext : Closing org.springframework.web.context.support.GenericWebApplicationContext@697f2062: startup date [Fri Nov 10 22:27:43 JST 2017]; root of context hierarchy
:check
:build
:buildDocker
Sending build context to Docker daemon 14.5MB
Step 1/5 : FROM openjdk:8-jdk-alpine
---> xxxxxxxxxxxx
Step 2/5 : VOLUME /tmp
---> Using cache
---> xxxxxxxxxxxx
Step 3/5 : ADD target/demo.jar app.jar
---> xxxxxxxxxxxx
Removing intermediate container xxxxxxxxxxxx
Step 4/5 : ENV JAVA_OPTS ""
---> Running in xxxxxxxxxxxx
---> xxxxxxxxxxxx
Removing intermediate container xxxxxxxxxxxx
Step 5/5 : ENTRYPOINT exec java $JAVA_OPTS -Djava.security.egd=file:/dev/./urandom -jar /app.jar
---> Running in xxxxxxxxxxxx
---> xxxxxxxxxxx
Removing intermediate container xxxxxxxxxxxx
Successfully built xxxxxxxxxxxx
Successfully tagged com.example/demo:0.0.1-SNAPSHOT
BUILD SUCCESSFUL
$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
com.example/demo 0.0.1-SNAPSHOT xxxxxxxxxxxx 1 minutes ago 116MB
It seems that it was completed successfully
Launching Spring Boot with Docker
$ docker run -p 8080:8080 -d com.example/demo:0.0.1-SNAPSHOT
xxxxxxxxxxxxxxxcf54172bd224611a7a184d3d454ee06a289143c191041706
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
xxxxxxxxxxxx com.example/demo:0.0.1-SNAPSHOT "/bin/sh -c 'exec ..." 36 seconds ago Up 10 seconds 0.0.0.0:8080->8080/tcp friendly_murdock
It seems to be running. When I access port 8080 on localhost, "Hello World!" Is displayed again.
Summary
I haven't adjusted the image name or tag this time. I also loosely deployed Docker images locally.
I was able to create a Docker image in the same way as creating a jar file with Gradle Since the adoption of Java 9 and OpenJDK is expected to progress in the future, there may be a future where Docker seems to be the first choice for running Spring Boot.
References
- https://spring.io/guides/gs/spring-boot-docker/
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