在docker-compose.yml中重用环境变量 [英] Re-using environment variables in docker-compose.yml

问题描述

是否可以重用在多个容器之间共享的环境变量？

Is it possible to re-use environment variables that are shared among multiple containers?

该想法是避免重复，如本例所示：

The idea is to avoid duplication, as illustrated in this example:

version: '2'

services:

  db:
    image: example/db
    ports:
      - "8443:8443" 
    container_name: db
    hostname: db
    environment:
      - USER_NAME = admin 
      - USER_PASSWORD = admin 

svc:
  image: example/svc
  depends_on:
    - db
  ports:
    - "9443:9443"
  container_name: svc
  hostname: svc
  environment:
    - DB_URL = https://db:8443
    - DB_USER_NAME = admin
    - DB_USER_PASSWORD = admin 

推荐答案

扩展选项可能不错，但它在<$ c中是不支持 $ c> 3.x 组成文件。其他可行的方法是：

The extends option can be nice but it's not supported in 3.x compose files. Other ways to go are:

1. 扩展名字段（组成文件3.4 +）

1. Extension fields (compose file 3.4+)

如果可以使用3.4+组成文件，则扩展名字段可能是最佳选择：

If you can use 3.4+ compose files, extension fields are probably the best option:

docker-compose.yml

version: '3.4'

x-common-variables: &common-variables
  VARIABLE: some_value
  ANOTHER_VARIABLE: another_value

services:
  some_service:
    image: someimage
    environment: *common-variables

  another_service:
    image: anotherimage
    environment:
      <<: *common-variables
      NON_COMMON_VARIABLE: 'non_common_value'

env_file 指令

docker-compose.yml

version: '3.2'

services:
  some_service:
    image: someimage
    env_file:
      - 'variables.env'

  another_service:
    image: anotherimage
    env_file:
      - 'variables.env'

variables.env

VARIABLE=some_value
ANOTHER_VARIABLE=another_value

.env 中的noreferrer>文件（或实际撰写环境中的变量）

.env file in project root (or variables at actual compose environment)

.env文件中的变量可以在服务配置中引用：

Variables from .env file can be referenced in service configuration:

docker-compose.yml

version: '3.2'

services:
  some_service:
    image: someimage
    environment:
      - VARIABLE

  another_service:
    image: anotherimage
    environment:
      - VARIABLE
      - ANOTHER_VARIABLE

.env

VARIABLE=some_value
ANOTHER_VARIABLE=another_value

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