简介
在文章《GraalVM和Spring Native尝鲜,一步步让Springboot启动飞起来,66ms完成启动》中,我们介绍了如何使用Spring Native和buildtools插件,打包出本地镜像,也打包成Docker镜像。本文探索一下,如果不通过这个插件来生成镜像。这样我们可以控制更多、了解更多。
创建Spring Boot项目
创建Spring Boot项目,引入Spring Native,我们主要使用的是Spring Native提供的AOT功能。如下:
<dependencies>
<dependency>
<groupId>org.springframework.experimental</groupId>
<artifactId>spring-native</artifactId>
<version>${spring-native.version}</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.experimental</groupId>
<artifactId>spring-aot-maven-plugin</artifactId>
<version>${spring-native.version}</version>
<executions>
<execution>
<id>test-generate</id>
<goals>
<goal>test-generate</goal>
</goals>
</execution>
<execution>
<id>generate</id>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
Build image的时候,我们需要引用依赖库,所以加上下面的插件:
<plugin>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<phase>package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/lib</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
接着先编译出Java class,命令如下:
$ mvn clean package
打包本地镜像
前面的命令打包完,在target目录下会有一个lib目录,我们需要用上。通过native-image
命令来生成镜像,如下:
$ native-image -cp ./target/classes/:target/lib/* com.pkslow.springboot.SpringbootGraalVMNativeMain Pkslow.SpringbootGraalVMNativeMain
这样就会生成一个可执行文件:Pkslow.SpringbootGraalVMNativeMain
执行如下:
$ ./Pkslow.SpringbootGraalVMNativeMain
使用了93ms来启动,还是很快的。
访问服务是正常的:
$ curl -i http://localhost:8080/hi-graalvm
HTTP/1.1 200
Content-Type: text/plain;charset=UTF-8
Content-Length: 67
Date: Wed, 02 Nov 2022 15:08:44 GMT
This message is from Spring Boot built/run by GraalVM/Spring Native
创建Docker镜像
先拉取基础镜像:
$ docker pull springci/graalvm-ce:java11-0.12.x
进入容器看一下里面的状况:
$ docker run -it --rm --entrypoint bash springci/graalvm-ce:java11-0.12.x
root@d9b54bdce70a:/# pwd
/
root@d9b54bdce70a:/# java --version
openjdk 11.0.15 2022-04-19
OpenJDK Runtime Environment GraalVM 22.1.1.0-dev (build 11.0.15+10-jvmci-22.1-b06)
OpenJDK 64-Bit Server VM GraalVM 22.1.1.0-dev (build 11.0.15+10-jvmci-22.1-b06, mixed mode, sharing)
root@d9b54bdce70a:/# which java
/opt/java/bin/java
root@d9b54bdce70a:/# which native-image
/opt/java/bin/native-image
准备一下Dockerfile如下:
FROM springci/graalvm-ce:java11-0.12.x
VOLUME /tmp
ARG PORT=8080
ARG TIME_ZONE=Asia/Shanghai
ENV TZ=${TIME_ZONE}
EXPOSE ${PORT}
RUN pwd
RUN mkdir /pkslow-application
WORKDIR /pkslow-application/
RUN cd /pkslow-application
COPY target/classes/ /pkslow-a