Java 应用程序不在 docker 容器内应用环境变量

Question

我正在尝试在 docker（在 Windows 10 上）中部署我的应用程序，与 Postgres 容器一起编写。当我执行 docker-compose up 时，我看到以下日志：

Starting postgres ... done
Recreating application ... done
Attaching to postgres, application
        postgres |
        postgres | PostgreSQL Database directory appears to contain a database; Skipping initialization
        postgres |
        postgres | 2021-08-20 14:51:49.721 UTC [1] LOG:  listening on IPv4 address "0.0.0.0", port 5432
        postgres | 2021-08-20 14:51:49.721 UTC [1] LOG:  listening on IPv6 address "::", port 5432
        postgres | 2021-08-20 14:51:49.741 UTC [1] LOG:  listening on Unix socket "/var/run/postgresql/.s.PGSQL.5432"
        postgres | 2021-08-20 14:51:49.858 UTC [21] LOG:  database system was interrupted; last known up at 2021-08-20 14:50:34 UTC
        postgres | 2021-08-20 14:51:51.363 UTC [21] LOG:  database system was not properly shut down; automatic recovery in progress
        postgres | 2021-08-20 14:51:51.377 UTC [21] LOG:  redo starts at 0/1661A88
        postgres | 2021-08-20 14:51:51.377 UTC [21] LOG:  invalid record length at 0/1661AC0: wanted 24, got 0
        postgres | 2021-08-20 14:51:51.377 UTC [21] LOG:  redo done at 0/1661A88
        postgres | 2021-08-20 14:51:51.471 UTC [1] LOG:  database system is ready to accept connections

然后我的应用程序的容器尝试启动并在横幅“Spring Boot”等之后出现错误：

application | 2021-08-20 14:52:23.440 ERROR 1 --- [           main] com.zaxxer.hikari.pool.HikariPool        : HikariPool-1 - Exception during pool initialization.
application |
application | 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.
application |   at org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:303) ~[postgresql-42.2.20.jar!/:42.2.20] 

这是我的 docker-compose.yml

version: "3"

services:
  db:
    image: postgres:11.13-alpine
    container_name: postgres
    ports:
    - 5432:5432
    volumes:
      - ./pgdata:/var/lib/postgresql/data
    environment:
      - POSTGRES_DB=my_db
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=root
      - PGDATA=/var/lib/postgresql/data/mnt
    restart: always
  app:
    build: .
    container_name: application
    ports:
      - 8085:8085
    environment:
      - POSTGRES_HOST=db
    restart: always
    links:
      - db

我的 Dockerfile：

FROM openjdk:11
ADD target/my-app.jar my-app.jar
EXPOSE 8085
ENTRYPOINT ["java" , "-jar", "my-app.jar"]

application.properties：

spring.datasource.url=jdbc:postgresql://${POSTGRES_HOST}:5432/my_db
spring.datasource.username=postgres
spring.datasource.password=root
spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.hibernate.ddl-auto=none
spring.liquibase.change-log=classpath:liquibase/changelog.xml
logging.level.org.springframework.jdbc.core = TRACE

有什么问题？为什么我的应用程序在 localhost 上寻找 Postgres 而没有应用环境变量？在 docker 容器内，postgres 的主机应该不同，不是吗？我什至尝试将 application.properties 中的 postgres 主机硬编码为 jdbc:postgresql://db:5432/my_db ，但它继续使用 localhost。我该如何解决？

Answer 1

尝试这样使用

environment:
        POSTGRES_HOST: db