spring-boot - 当通过 Dockerfile 上的 gradle 图像触发时，Jooq 无法找到数据库

Question

我有一个 Dockerfile，它使用 gradle 构建我的 Spring Boot 应用程序，然后将其复制到容器中并触发它。这是它的外观:

FROM gradle:5.4.1-jdk8-alpine AS build
COPY --chown=gradle:gradle . /home/gradle/src
WORKDIR /home/gradle/src
RUN gradle build --no-daemon

FROM openjdk:8-jdk-alpine
EXPOSE 8080
RUN mkdir /app
COPY --from=build /home/gradle/src/build/libs/*.jar yurlapp.jar
ENTRYPOINT ["java","-jar" , "/yurlapp.jar"]

这很简单，它将执行 Gradle 并将 jar 添加到 docker 容器中。到现在为止还挺好。提供数据库后，此 Dockerfile 将在 docker-compose.yml 中使用(应用程序需要该数据库才能工作)。这就是 docker-compose.yml 的样子:

version: '2.1'
services:
  yurldb:
    image: postgres:11
    container_name: yurldb
    networks:
      - yunet
    ports:
      - 5432:5432
    environment:
      - POSTGRES_DB=yurldb
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=somepassword
    volumes:
      - ./init.sql:/docker-entrypoint-initdb.d/
      - yudata:/var/lib/postgresql/data
    healthcheck:
      test: ["CMD-SHELL", "pg_isready -U postgres"]
      interval: 10s
      timeout: 10s
      retries: 5
  flyway:
    image: boxfuse/flyway
    command: -url=jdbc:postgresql://yurldb:5432/yurldb -schemas=public -user=postgres -password=somepassword migrate
    networks:
      - yunet
    volumes:
      - .:/flyway/sql
    depends_on:
      yurldb:
        condition: service_healthy
  yurlapp:
    container_name: yurlapp
    image: javing/yurlapp:0.0.1
    build:
      context: .
      dockerfile: Dockerfile
    networks:
      - yunet
    ports:
      - 8080:8080
    environment:
      - DB_HOST=yurldb #the name of the DB container is used as url
    depends_on:
      yurldb:
        condition: service_healthy
      flyway:
        condition: service_healthy
networks:
  yunet:
volumes:
  yudata:

如您所见，应用程序镜像是最后构建的，一旦数据库镜像准备好并且在 flyway 执行迁移之后。我在构建应用程序期间发生的问题。
因此，一旦 gradle 启动，它将完成它必须做的所有事情。但在某一时刻，它需要 Jooq，根据数据库上的现有表自动生成一些类。在这里出了点问题。构建爆炸并告诉我:

Task :generateSampleJooqSchemaSource FAILED

FAILURE: Build failed with an exception.

* Where:
Build file '/home/gradle/src/build.gradle' line: 81

* What went wrong:
Execution failed for task ':generateSampleJooqSchemaSource'.
> jOOQ source code generation failed:

  Jun 01, 2020 7:37:39 PM org.jooq.tools.JooqLogger info
  INFO: Initialising properties  : /home/gradle/src/build/tmp/generateSampleJooqSchemaSource/config.xml
  Jun 01, 2020 7:37:39 PM org.jooq.tools.JooqLogger error
  SEVERE: Cannot read /home/gradle/src/build/tmp/generateSampleJooqSchemaSource/config.xml. Error : Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
  org.postgresql.util.PSQLException: Connection to localhost:5432 refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:285)
    at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
    at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:211)
    at org.postgresql.Driver.makeConnection(Driver.java:459)
    at org.postgresql.Driver.connect(Driver.java:261)
    at org.jooq.codegen.GenerationTool.run0(GenerationTool.java:342)
    at org.jooq.codegen.GenerationTool.run(GenerationTool.java:221)
    at org.jooq.codegen.GenerationTool.generate(GenerationTool.java:216)
    at org.jooq.codegen.GenerationTool.main(GenerationTool.java:188)
  Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.postgresql.core.PGStream.<init>(PGStream.java:81)
    at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:93)
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:197)
    ... 8 more

它说它无法连接到数据库。这是为什么？这是我在 build.gradle 文件中的 Jooq 配置

jooq {
    sample(sourceSets.main) {
        jdbc {
            driver = 'org.postgresql.Driver'
            url = 'jdbc:postgresql://localhost:5432/yurldb'
            user = 'postgres'
            password = 'somepassword'
        }
        generator {
            database() {
                name = 'org.jooq.meta.postgres.PostgresDatabase'
                inputSchema = 'public'
                includes = '.*'
            }
            target {
                packageName = 'com.javing.yurl'
                directory = 'build/generated/java'
            }
        }
    }
}

tasks.generateSampleJooqSchemaSource.with {
    def out = new ByteArrayOutputStream()
    javaExecSpec = { JavaExecSpec s ->
        s.standardOutput = out
        s.errorOutput = out
        s.ignoreExitValue = true
        s.jvmArgs '-Xmx512M'
    }
    execResultHandler = { ExecResult r ->
        if (r.exitValue != 0) {
            throw new RuntimeException('jOOQ source code generation failed:\n\n' + out.toString())
        }
    }
}

我很困惑，我不确定我是否理解发生了什么。如果我要使用 docker-compose 仅​​自行启动数据库镜像，然后从终端手动运行 gradle(而不是来自 docker 的 gradle)，那么这些类将毫无问题地生成。所以我不知道何时使用 Dockerfile Jooq 中的 gradle 无法找到数据库。任何的想法？
我是否还需要以某种方式从 Dockerfile 触发 Jooq，就像我触发 gradle 一样？有人可以帮我解决这个问题，我有点卡住了。

更新
我尝试将 jooq 配置中的 url 更改为使用 yurldb 而不是 localhost 因为可能在容器内联网时，url resloves 到容器的名称，但这不起作用。会发生什么:

FAILURE: Build failed with an exception.

* Where:
Build file '/home/gradle/src/build.gradle' line: 81

* What went wrong:
Execution failed for task ':generateSampleJooqSchemaSource'.
> jOOQ source code generation failed:

  Jun 01, 2020 8:29:57 PM org.jooq.tools.JooqLogger info
  INFO: Initialising properties  : /home/gradle/src/build/tmp/generateSampleJooqSchemaSource/config.xml
  Jun 01, 2020 8:30:08 PM org.jooq.tools.JooqLogger error
  SEVERE: Cannot read /home/gradle/src/build/tmp/generateSampleJooqSchemaSource/config.xml. Error : The connection attempt failed.
  org.postgresql.util.PSQLException: The connection attempt failed.
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:297)
    at org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:49)
    at org.postgresql.jdbc.PgConnection.<init>(PgConnection.java:211)
    at org.postgresql.Driver.makeConnection(Driver.java:459)
    at org.postgresql.Driver.connect(Driver.java:261)
    at org.jooq.codegen.GenerationTool.run0(GenerationTool.java:342)
    at org.jooq.codegen.GenerationTool.run(GenerationTool.java:221)
    at org.jooq.codegen.GenerationTool.generate(GenerationTool.java:216)
    at org.jooq.codegen.GenerationTool.main(GenerationTool.java:188)
  Caused by: java.net.SocketTimeoutException: connect timed out
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at org.postgresql.core.PGStream.<init>(PGStream.java:81)
    at org.postgresql.core.v3.ConnectionFactoryImpl.tryConnect(ConnectionFactoryImpl.java:93)
    at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:197)
    ... 8 more

Answer 1

问题是你有 localhost作为 jooq 配置中的数据库主机build.gradle 中的插件.

您已正确设置 DB_HOST 的环境变量在其他地方，所以我假设您了解服务名称是 DNS 名称，当它们连接到公共(public)网络时，您可以使用它来引用其他服务。你应该改变

url = 'jdbc:postgresql://localhost:5432/yurldb'

到

url = 'jdbc:postgresql://yurldb:5432/yurldb'

或者您可以在应用服务的环境变量中获取 db 的主机，然后从 build.gradle 中读取它:

def db = System.getenv('DB_HOST')
url = "jdbc:postgresql://${db}:5432/yurldb"