Gradle构建Java应用部署Heroku失败：Web进程无法绑定$PORT

问题现象 #

使用Gradle部署Java Jooby应用到Heroku后，执行heroku open页面长时间空白，Heroku日志返回R10启动超时错误。

错误日志 #

2022-10-10T05:52:17.000000+00:00 app[api]: Build succeeded
2022-10-10T05:53:40.640805+00:00 heroku[web.1]: Error R10 (Boot timeout) -> Web process failed to bind to $PORT within 90 seconds of launch
2022-10-10T05:53:40.718527+00:00 heroku[web.1]: Stopping process with SIGKILL
2022-10-10T05:53:40.842261+00:00 heroku[web.1]: Process exited with status 137
2022-10-10T05:53:40.890653+00:00 heroku[web.1]: State changed from starting to crashed

当前配置与代码 #

Procfile #

web: java $JAVA_OPTS -Dserver.port=$PORT -jar app/build/libs/app-all.jar

build.gradle #

/*
 * This file was generated by the Gradle 'init' task.
 *
 * This generated file contains a sample Java application project to get you started.
 * For more details take a look at the 'Building Java & JVM projects' chapter in the Gradle
 * User Manual available at https://docs.gradle.org/7.4/userguide/building_java_projects.html
 */

plugins {
    // Apply the application plugin to add support for building a CLI application in Java.
    id 'application'  
}

jar {
  manifest {
    attributes(
      'Main-Class': 'group5MentorMatcher.Main',
    )
  }
}

task fatJar(type: Jar) {
  duplicatesStrategy = DuplicatesStrategy.EXCLUDE
  manifest.from jar.manifest
  classifier = 'all'
  from {
    configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
  } {
    exclude "META-INF/*.SF"
    exclude "META-INF/*.DSA"
    exclude "META-INF/*.RSA"
    exclude "META-INF/*.TXT"
  }
  with jar
}

repositories {
    // Use Maven Central for resolving dependencies.
    mavenCentral()
}

dependencies {
    //Dependencies for testing
    def junitVer = "5.8.2";
    testImplementation group: "org.junit.jupiter", name: "junit-jupiter-api", version: junitVer;
    testRuntimeOnly group: "org.junit.jupiter", name: "junit-jupiter-engine", version: junitVer;
    testImplementation group: "org.hamcrest", name: "hamcrest", version: "2.2";

    // Use JUnit Jupiter for testing.
    testImplementation 'org.junit.jupiter:junit-jupiter:5.8.1'

    // This dependency is used by the application.
    implementation 'com.google.guava:guava:30.1.1-jre'
    
    // Use postgres to connect to the database
    implementation 'org.postgresql:postgresql:42.4.0'

    // guava
        implementation group: 'com.google.guava', name: 'guava', version: '30.1.1-jre'

    // jooby
    def joobyVer =  '2.13.0'
    implementation group: 'io.jooby', name: 'jooby-netty', version: joobyVer
    implementation group: 'io.jooby', name: 'jooby-gson', version: joobyVer
    implementation group: 'io.jooby', name: 'jooby-swagger-ui', version: joobyVer

    //logging
        implementation group: 'org.slf4j', name: 'slf4j-api', version: '1.7.36'
        implementation group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.10'

        implementation group: 'com.zaxxer', name: 'HikariCP', version: '4.0.3'
        implementation group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.5'

        def jdbiVer = '3.21.0'
        implementation group: 'org.jdbi', name: 'jdbi3-core', version: jdbiVer
        implementation group: 'org.jdbi', name: 'jdbi3-sqlobject', version: jdbiVer
}

application {
    // Define the main class for the application.
    mainClass = 'group5MentorMatcher.Main'
}

task stage(dependsOn: ['build', 'clean'])
build.mustRunAfter clean

task copyToLib(type: Copy) {
    from configurations.compileClasspath
    into 'build/libs'
}

stage.dependsOn(copyToLib)

gradle.taskGraph.whenReady {
  taskGraph ->
    if (taskGraph.hasTask(stage)) {
      test.enabled = false
    }
}
artifacts {
    archives fatJar
}

sourceSets {
    'static' {
        resources {
            srcDirs = ['static']
        }
        java{
            srcDirs = []
        }
    }
}

Main类核心代码 #

public class Main extends Jooby {
    private final PersonDAO personDAO = JDBIDaoFactory.getPersonDAO();
    private final MentorDAO mentorDAO = JDBIDaoFactory.getMentorDAO();
    private final MenteeDAO menteeDAO = JDBIDaoFactory.getMenteeDAO();
    private final MatchDAO matchDAO = JDBIDaoFactory.getMatchDAO();
    private final UndergraduateExperienceDAO undergraduateDAO = JDBIDaoFactory.getUndergraduateExperienceDAO();
    private final PostgraduateExperienceDAO postgraduateDAO = JDBIDaoFactory.getPostgraduateExperienceDAO();
    private final PostgradCourseDAO pgCourseDAO = JDBIDaoFactory.getPostgradCourseDAO();
    private final UndergradCourseDAO ugCourseDAO = JDBIDaoFactory.getUndergradCourseDAO();

    public Main() {
        setServerOptions(new ServerOptions().setPort(8072));

        install(new GsonModule());
        install(new OpenAPIModule());

        assets("/openapi.json", "mentor-matcher.json");
        assets("/openapi.yaml", "mentor-matcher.yaml");
        assets("/*", Paths.get("app/static"));
        
        mount(new PersonModule(personDAO));
        mount(new MentorModule(mentorDAO));
        mount(new MenteeModule(menteeDAO));
        mount(new MatchModule(matchDAO));
        mount(new UndergraduateExperienceModule(undergraduateDAO));
        mount(new PostgraduateExperienceModule(postgraduateDAO));
        mount(new PostgradCourseModule(pgCourseDAO));
        mount(new UndergradCourseModule(ugCourseDAO));
    }
}

解决方案 #

核心问题 #

Heroku要求Web进程必须绑定到其动态分配的$PORT环境变量指定的端口，但你的Main类硬编码了端口8072，完全忽略了Procfile中传入的-Dserver.port=$PORT参数，导致应用无法绑定到正确端口，触发R10超时错误。

修改步骤 #

修改Main类的端口配置逻辑，读取系统属性（对应-Dserver.port=$PORT），同时保留本地开发默认端口：

public class Main extends Jooby {
    // DAO实例初始化...

    public Main() {
        // 读取系统属性中的server.port，默认值8072用于本地开发
        int port = Integer.parseInt(System.getProperty("server.port", "8072"));
        setServerOptions(new ServerOptions().setPort(port));

        // 模块安装与路由挂载...
    }

    // 补充启动入口方法（Jooby应用必需）
    public static void main(String[] args) {
        runApp(args, Main::new);
    }
}

验证流程 #

1. 提交修改：git add . && git commit -m "fix: use heroku dynamic port" && git push heroku main
2. 查看部署日志：heroku logs --tail，确认应用成功绑定到Heroku分配的端口
3. 重新访问应用：heroku open

内容的提问来源于stack exchange，提问作者othnuk