Docker Compose无法读取USER_NAME等环境变量问题求助

环境变量文件（env.env） #

USER_NAME=user_name
HOME_DIR=home

Docker Compose配置（docker-compose.yml） #

services:
  serviceName:
    container_name: container_name
    image: image

    ports:
      - target: 5000
        published: 5000

    environment:
      - YOLO_VERBOSE=False

    env_file:
      - path_to_the_env_file.env

    volumes:
      - datasets:/home/${USER_NAME}/rest_of_the_path
      - model:/home/${USER_NAME}/rest_of_the_path

启动时警告信息 #

WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "USER_NAME" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string. 
WARN[0000] The "HOME_DIR" variable is not set. Defaulting to a blank string.

使用版本 #

• Docker Compose：v2.32.4
• Docker：24.0.7, build 24.0.7-0ubuntu2~22.04.1

已尝试的无效操作 #

1. 在docker-compose.yml的environment字段直接定义变量：

environment:
  - YOLO_VERBOSE=False
  - USER_NAME=userName
  - HOME_DIR=home

2. 升级Docker Compose版本

以上操作均未解决问题，求帮助。

核心问题：Docker Compose解析volumes字段中的变量时，只会读取宿主机的环境变量，容器内的env_file、environment定义的变量不生效。

下面是具体解决办法：

方法1：启动时临时导出宿主机变量 #

执行启动命令前，先把变量导入当前shell环境：

export USER_NAME=user_name
export HOME_DIR=home
docker-compose up -d

或者一次性组合执行：

USER_NAME=user_name HOME_DIR=home docker-compose up -d

方法2：使用Compose默认识别的.env文件 #

Docker Compose会自动加载当前目录下的.env文件，把变量放到这个文件中：

USER_NAME=user_name
HOME_DIR=home

之后直接执行docker-compose up -d即可，无需在docker-compose.yml中配置env_file（如果仅需给Compose解析用的话）。

方法3：用扩展字段统一管理变量 #

如果想让容器内变量和卷配置变量保持一致，可以用Compose的扩展字段定义变量集合，再分别引用：

x-env-vars: &env-vars
  USER_NAME: user_name
  HOME_DIR: home

services:
  serviceName:
    container_name: container_name
    image: image
    ports:
      - target: 5000
        published: 5000
    environment:
      <<: *env-vars
      YOLO_VERBOSE: False
    volumes:
      - datasets:/home/${USER_NAME}/rest_of_the_path
      - model:/home/${USER_NAME}/rest_of_the_path

启动时仍需通过宿主机导出变量或.env文件提供变量值。

关键说明 #

• 卷路径是Compose在宿主机侧解析生成的（即使是命名卷的内部挂载路径），所以容器内的环境变量无法影响这个解析过程。
• env_file和environment定义的变量仅对容器内部运行环境生效，不作用于Compose对配置文件本身的解析。

内容的提问来源于stack exchange，提问作者ilie alexandru