在spring boot3中使用native image

flydean發表於2023-01-30

簡介

在之前spring boot3文章中我們介紹了,spring boot3的一個重要特性就是支援把spring boot3的應用編譯成為GraalVM的Native Image。

今天我們用具體的例子來給大家演示一下如何正確的將spring boot3的應用編譯成為native image。

安裝GraalVM

如果要把spring boot3的app編譯成為native應用,需要GraalVM的支援。

什麼是GraalVM呢?

從名字就可以看出來GraalVM是一個虛擬機器,它的主要目標就是提升java應用程式的效能,並且消耗更少的資源。

它在java HotSpot JVM的基礎上新增了JIT編譯器和AOT來實現將應用編譯成為本地可執行檔案。除了java之外,GraalVM還支援JavaScript、Ruby、Python等多種程式語言。

所以,為什麼要用GraalVM呢?一個字:快。

安裝GraalVM也比較簡單,我們進入它的官方下載頁面下載對應的版本即可:https://www.oracle.com/downloads/graalvm-downloads.html。

GraalVM跟JDK一樣也有兩個版本,社群版和企業版本,大家可以根據需要自行選擇。

要注意的是spring boot3需要GraalVM 22.3以上的版本支援,大家可不要下載錯了。

下載完成之後,我們可以像正常安裝JDK一樣來安裝GraalVM,這裡以mac為例,假如我們安裝的目錄是/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0,那麼我們需要配置對應的JAVA_HOME和PATH環境變數如下:

 export PATH=/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0/Contents/Home/bin:$PATH

 export JAVA_HOME=/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0/Contents/Home

PATH中有一個非常重要的命令叫做gu,如果不新增PATH,那麼在使用中就可能遇到下面的異常:

'gu' tool wasn't found. This probably means that JDK at isn't a GraalVM distribution.

安裝完畢之後可以透過下面的命令來進行驗證:

java -version
java version "17.0.5" 2022-10-18 LTS
Java(TM) SE Runtime Environment GraalVM EE 22.3.0 (build 17.0.5+9-LTS-jvmci-22.3-b07)
Java HotSpot(TM) 64-Bit Server VM GraalVM EE 22.3.0 (build 17.0.5+9-LTS-jvmci-22.3-b07, mixed mode, sharing)

如果是在mac環境下,還需要執行下面的命令來解除對graalvm的隔離限制:

 sudo xattr -r -d com.apple.quarantine /path/to/graalvm

否則在使用中就會遇到下面的問題:

新增Native Image支援

我們安裝GraalVM的目的就是使用它的native Image特性。native image是一個單獨的jar包,我們可以執行下面的命令來進行安裝:

gu install native-image

其中gu就是/Library/Java/JavaVirtualMachines/graalvm-ee-java17-22.3.0/Contents/Home/bin中的命令。

下載的過程中還需要輸入一個有效的郵件,並進行郵箱校驗。然後一路ENTER就可以了。

當然,你還可以把Oracle GraalVM Enterprise Edition Native Image下載到本地,然後使用gu install -L來進行本地安裝。

好了,到目前為止,一切準備妥當,我們接下來看看如何把spring boot3的應用打包成為native image吧。

構建spring boot3應用

這裡我們使用的是maven,所以需要新增下面的spring boot3的依賴:

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>3.0.1</version>
        <relativePath/> 
    </parent>

因為要構建native image,所以我們還需要用到下面的一個native-maven-plugin外掛:

            <plugin>
                <groupId>org.graalvm.buildtools</groupId>
                <artifactId>native-maven-plugin</artifactId>
            </plugin>

這裡我們只建立了一個非常簡單的main方法:

@SpringBootApplication
public class NativeImageApplication {

    public static void main(String[] args) {
        SpringApplication.run(NativeImageApplication.class, args);
    }

}

然後,我們嘗試執行 mvn native:build來構建spring boot3應用程式。

記得在build之前一定先要編譯好專案。

很可惜,你會發現下面的異常:

[INFO] --- native-maven-plugin:0.9.19:build (default-cli) @ native-image ---
[WARNING] 'native:build' goal is deprecated. Use 'native:compile-no-fork' instead.
[INFO] Found GraalVM installation from JAVA_HOME variable.
...
Error: Please specify class (or <module>/<mainclass>) containing the main entry point method. (see --help)

從上面的異常我們發現了兩個問題,第一個問題是一個警告,它推薦我們使用native:compile-no-fork。

第二個問題是說找不到mainclass,根據異常資訊,我們在pom的plugin中新增下面的配置資訊,如下所示:

<plugin>
                <groupId>org.graalvm.buildtools</groupId>
                <artifactId>native-maven-plugin</artifactId>
                <configuration>
                    <!-- imageName用於設定生成的二進位制檔名稱 -->
                    <imageName>${project.artifactId}</imageName>
                    <!-- mainClass用於指定main方法類路徑 -->
                    <mainClass>com.flydean.nativeimage.NativeImageApplication</mainClass>
                    <buildArgs>
                        --no-fallback
                    </buildArgs>
                </configuration>
                <executions>
                    <execution>
                        <id>build-native</id>
                        <goals>
                            <goal>compile-no-fork</goal>
                        </goals>
                        <phase>package</phase>
                    </execution>
                </executions>
            </plugin>

然後重新執行mvn native:compile-no-fork:

GraalVM Native Image: Generating 'native-image' (executable)...
========================================================================================================================
[1/7] Initializing...                                                                                    (4.3s @ 0.25GB)
 Version info: 'GraalVM 22.3.0 Java 17 EE'
 Java version info: '17.0.5+9-LTS-jvmci-22.3-b07'
 C compiler: cc (apple, arm64, 14.0.0)
 Garbage collector: Serial GC
 1 user-specific feature(s)
 - org.springframework.aot.nativex.feature.PreComputeFieldFeature
Field org.apache.commons.logging.LogAdapter#log4jSpiPresent set to true at build time
Field org.apache.commons.logging.LogAdapter#log4jSlf4jProviderPresent set to true at build time
Field org.apache.commons.logging.LogAdapter#slf4jSpiPresent set to true at build time
Field org.apache.commons.logging.LogAdapter#slf4jApiPresent set to true at build time
Field org.springframework.core.NativeDetector#imageCode set to true at build time
Field org.springframework.core.KotlinDetector#kotlinPresent set to false at build time
Field org.springframework.core.KotlinDetector#kotlinReflectPresent set to false at build time
Field org.springframework.format.support.DefaultFormattingConversionService#jsr354Present set to false at build time
Field org.springframework.cglib.core.AbstractClassGenerator#imageCode set to true at build time
[2/7] Performing analysis...  [**********]                                                              (24.8s @ 4.57GB)
  10,266 (89.50%) of 11,470 classes reachable
  16,675 (63.53%) of 26,248 fields reachable
  53,776 (60.71%) of 88,575 methods reachable
     469 classes,   140 fields, and 2,281 methods registered for reflection
      63 classes,    69 fields, and    55 methods registered for JNI access
       5 native libraries: -framework CoreServices, -framework Foundation, dl, pthread, z
[3/7] Building universe...                                                                               (5.0s @ 2.72GB)
[4/7] Parsing methods...      [**]                                                                       (4.4s @ 2.42GB)
[5/7] Inlining methods...     [***]                                                                      (1.3s @ 3.87GB)
[6/7] Compiling methods...    [********]                                                                (70.0s @ 1.04GB)
[7/7] Creating image...                                                                                  (4.7s @ 3.35GB)
  30.27MB (58.75%) for code area:    30,771 compilation units
  20.50MB (39.79%) for image heap:  305,579 objects and 93 resources
 769.52KB ( 1.46%) for other data
  51.52MB in total
------------------------------------------------------------------------------------------------------------------------
Top 10 packages in code area:                               Top 10 object types in image heap:
   2.02MB com.oracle.svm.core.code                             5.79MB byte[] for code metadata
   1.77MB sun.security.ssl                                     2.31MB byte[] for java.lang.String
   1.29MB java.util                                            2.09MB byte[] for general heap data
 929.52KB java.lang.invoke                                     2.07MB java.lang.String
 925.96KB com.sun.crypto.provider                              1.76MB java.lang.Class
 802.99KB java.lang                                          671.09KB byte[] for embedded resources
 633.35KB sun.nio.ch                                         567.26KB byte[] for reflection metadata
 625.89KB java.util.concurrent                               481.22KB com.oracle.svm.core.hub.DynamicHubCompanion
 601.86KB org.apache.tomcat.util.net                         450.06KB java.util.HashMap$Node
 594.48KB sun.security.x509                                  401.78KB java.util.concurrent.ConcurrentHashMap$Node
  20.02MB for 397 more packages                                3.40MB for 2297 more object types
------------------------------------------------------------------------------------------------------------------------
                        9.5s (7.9% of total time) in 50 GCs | Peak RSS: 3.75GB | CPU load: 4.39
------------------------------------------------------------------------------------------------------------------------
Produced artifacts:
 /Users/learn-springboot3/learn-springboot3/native-image/target/native-image (executable)
 /Users/learn-springboot3/learn-springboot3/native-image/target/native-image.build_artifacts.txt (txt)
========================================================================================================================
Finished generating 'native-image' in 2m 0s.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  02:01 min
[INFO] Finished at: 2023-01-05T20:43:39+08:00
[INFO] ------------------------------------------------------------------------

經過漫長的等待,我們終於build完成了。

因為我們的artifactId叫做native-image,所以最終在target目錄下面生成了一個叫做native-image的可執行檔案:

.
├── classes
│   ├── application.properties
│   └── com
│       └── flydean
│           └── nativeimage
│               └── NativeImageApplication.class
├── generated-sources
│   └── annotations
├── generated-test-sources
│   └── test-annotations
├── maven-archiver
│   └── pom.properties
├── maven-status
│   └── maven-compiler-plugin
│       ├── compile
│       │   └── default-compile
│       │       ├── createdFiles.lst
│       │       └── inputFiles.lst
│       └── testCompile
│           └── default-testCompile
│               ├── createdFiles.lst
│               └── inputFiles.lst
├── native-image
├── native-image-0.0.1-SNAPSHOT.jar
├── native-image-0.0.1-SNAPSHOT.jar.original
├── native-image.build_artifacts.txt
├── surefire-reports
│   ├── TEST-com.flydean.nativeimage.NativeImageApplicationTests.xml
│   └── com.flydean.nativeimage.NativeImageApplicationTests.txt
└── test-classes
    └── com
        └── flydean
            └── nativeimage
                └── NativeImageApplicationTests.class

20 directories, 14 files

如果你這時候執行target/native-image,那麼很可能得到下面的異常:

[main] DEBUG org.springframework.context.aot.AotApplicationContextInitializer - Initializing ApplicationContext with AOT
[main] ERROR org.springframework.boot.SpringApplication - Application run failed
java.lang.IllegalArgumentException: Could not find class [com.flydean.nativeimage.NativeImageApplication__ApplicationContextInitializer]
        at org.springframework.util.ClassUtils.resolveClassName(ClassUtils.java:333)

這是因為我們缺少一些spring boot的AOT元檔案資訊,正確的做法是使用下面的命令:

mvn clean package -Pnative

它實際上執行的是下面的幾個命令:

mvn spring-boot:process-aot
mvn spring-boot:process-test-aot
mvn spring-boot:build-image

最終我們得到編譯好的native-image資訊,執行得到下面的結果:

2023-01-05T17:07:11.692+08:00  INFO 69299 --- [           main] c.f.nativeimage.NativeImageApplication   : Starting AOT-processed NativeImageApplication using Java 17.0.5 with PID 69299 (/Users/wayne/data/git/ddean2009/learn-springboot3/learn-springboot3/native-image/target/native-image started by wayne in /Users/wayne/data/git/ddean2009/learn-springboot3/learn-springboot3/native-image)
2023-01-05T17:07:11.693+08:00  INFO 69299 --- [           main] c.f.nativeimage.NativeImageApplication   : No active profile set, falling back to 1 default profile: "default"
2023-01-05T17:07:11.709+08:00  INFO 69299 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2023-01-05T17:07:11.710+08:00  INFO 69299 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2023-01-05T17:07:11.710+08:00  INFO 69299 --- [           main] o.apache.catalina.core.StandardEngine    : Starting Servlet engine: [Apache Tomcat/10.1.4]
2023-01-05T17:07:11.717+08:00  INFO 69299 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2023-01-05T17:07:11.717+08:00  INFO 69299 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 24 ms
2023-01-05T17:07:11.729+08:00  INFO 69299 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2023-01-05T17:07:11.729+08:00  INFO 69299 --- [           main] c.f.nativeimage.NativeImageApplication   : Started NativeImageApplication in 0.053 seconds (process running for 0.072)

總結

從執行情況來看,native-image的啟動速度非常快,應該可以提升不少的效能。

感興趣的小夥伴趕緊用起來吧。

本文的例子https://github.com/ddean2009/learn-springboot3

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