使用docker时Spring无法连接到postgres

Question

我正在尝试将使用另一个容器化 Postgres 数据库的 Spring Boot 项目容器化，但似乎 Spring 项目无法连接到数据库，因为它无法解析主机名。

Dockerfile：

FROM maven:3.6.0-jdk-11
WORKDIR /app
COPY . /app
RUN mvn clean install spring-boot:run -q

Docker 撰写：

version: "3.7"

services:
  postgres:
    image: postgres
    container_name: db
    expose:
      - "5432"
    ports:
      - "5432:5432"
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: nanobox
    networks:
      - app-network
  
  backend:
    restart: always
    build:
      context: nanobox
    volumes:
      - ./nanobox:/app
    environment:
      - SECRET=bigsecret
    ports:
      - 8081:8081
    networks:
      - app-network
    depends_on:
      - postgres


networks:
  app-network:
    driver: bridge

application.properties：

logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE
#debug=false

spring.datasource.platform=postgres
spring.datasource.url=jdbc:postgresql://postgres:5432/nanobox
spring.datasource.username=postgres
spring.datasource.password=postgres
spring.jpa.generate-ddl=true
spring.jpa.database=postgresql
spring.jpa.hibernate.ddl-auto=update
#spring.jpa.properties.hibernate.jdbc.lob.not_contextual_creation=true
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
debug=true
spring.mvc.log-request-details=true
auth.secret={SECRET}
storage.prefix = /tmp/uploads/

docker compose up 失败，但出现以下异常：

#8 44.67 Caused by: javax.persistence.PersistenceException: [PersistenceUnit: default] Unable to build Hibernate SessionFactory; nested exception is org.hibernate.exception.JDBCConnectionException: Unable to open JDBC Connection for DDL execution
    [..]
#8 44.67 Caused by: org.hibernate.exception.JDBCConnectionException: Unable to open JDBC Connection for DDL execution
    [..]
#8 44.68 Caused by: org.postgresql.util.PSQLException: The connection attempt failed.
    [..]
#8 44.68 Caused by: java.net.UnknownHostException: postgres

似乎由于某种原因docker compose拒绝在Spring应用程序之前启动postgres容器，甚至命令：

docker compose up postgres backend

结果：

[+] Building 8.3s (8/8) FINISHED                                                                                                                                                                                                                                                                                            
 => [internal] load build definition from Dockerfile                                                                                                                                                                                                                                                                   0.0s
 => => transferring dockerfile: 31B                                                                                                                                                                                                                                                                                    0.0s
 => [internal] load .dockerignore                                                                                                                                                                                                                                                                                      0.0s
 => => transferring context: 2B                                                                                                                                                                                                                                                                                        0.0s
 => [internal] load metadata for docker.io/library/maven:3.6.0-jdk-11                                                                                                                                                                                                                                                  1.5s
 => [1/4] FROM docker.io/library/maven:3.6.0-jdk-11@sha256:6a0430ded2cfaba7e16080f4cc097c9c65d1406b3b235d0fcfcfd84c354c4177                                                                                                                                                                                            0.0s
 => [internal] load build context                                                                                                                                                                                                                                                                                      0.0s
 => => transferring context: 18.55kB                                                                                                                                                                                                                                                                                   0.0s
 => CACHED [2/4] WORKDIR /app                                                                                                                                                                                                                                                                                          0.0s
 => CACHED [3/4] COPY . /app    

Answer 1

您正在尝试从 Dockerfile RUN 指令运行 mvn spring-boot:run；这发生在您尝试构建映像时，而不是在您稍后运行容器时。 （这类似于使用javac 编译源文件和java 运行构建的类文件之间的区别。）由于超出此答案范围的原因，构建阶段无法连接到其他容器，即使它们在同一个 docker-compose.yml 文件中声明。

将 Dockerfile 分成两行来构建应用程序，然后将其作为主容器命令运行：

FROM maven:3.6.0-jdk-11
WORKDIR /app
COPY . .      # (don't repeat /app directory name)

# At build time, only compile the application but do not run it
RUN mvn clean install

# When you launch the container, this will be the main command
CMD mvn spring-boot:run

Answer 2

@david-maze 的解决方案对我来说几乎是好的。但是，我用下面的 Dockerfile 解决了这个问题：

FROM maven:3.6.0-jdk-11
WORKDIR /app
COPY . .

# At build time, only compile the application but do not run it
RUN mvn clean package -DskipTests -q

# When you launch the container, this will be the main command
CMD mvn spring-boot:run

还必须为数据库容器添加别名：

postgres:
    image: postgres
    container_name: db
    expose:
      - "5432"
    ports:
      - "5432:5432"
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: nanobox
      networks:
        some-net:
          aliases:
            - auth-module.dev

Maven 正在运行导致容器启动失败的测试，因为没有数据库。