docker - docker-compose不初始化容器环境变量

Question

我正在尝试执行简单的代码。

docker-compose.yml

version: '3.7'

services:
  test-environment:
    image: alpine:3.9
    environment: 
      VAR1: 'variable 1'
      VAR2: '222'
    command: echo variable1 = $VAR1; variable2 = $VAR2

预期行为:在输出中看到

variable1 = variable 1; variable2 = 222

但是之后

docker-compose up

我下一个:

WARNING: The VAR1 variable is not set. Defaulting to a blank string.
WARNING: The VAR2 variable is not set. Defaulting to a blank string.
Recreating project_test-environment_1 ... done
Attaching to project_test-environment_1
test-environment_1  | variable1 = ; variable2 =
project_test-environment_1 exited with code 0

似乎环境变量未初始化。使用替代语法

environment:
 - VAR1='variable 1'
 - VAR2=222

也得到相同的结果。

docker 信息输出:

Containers: 3
Running: 0
Paused: 0
Stopped: 3
Images: 5
Server Version: 18.09.2
Storage Driver: overlay2
Backing Filesystem: extfs
Supports d_type: true
Native Overlay Diff: true
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
 Volume: local
 Network: bridge host macvlan null overlay
 Log: awslogs fluentd gcplogs gelf journald json-file local logentries 
 splunk syslog
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 9754871865f7fe2f4e74d43e2fc7ccd237edcbce
runc version: 09c8266bf2fcf9519a651b04ae54c967b9ab86ec
init version: fec3683
Security Options:
 seccomp
 Profile: default
Kernel Version: 4.9.125-linuxkit
Operating System: Docker for Windows
OSType: linux
Architecture: x86_64
CPUs: 1
Total Memory: 973.8MiB
Name: linuxkit-00155d694b07
ID: NA32:YPM3:D5GL:JQBM:H4BN:LE2B:4HLN:5B4A:AI7T:6SDS:LSVZ:P74L
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): true
 File Descriptors: 22
 Goroutines: 47
 System Time: 2019-05-14T08:44:02.5767035Z
 EventsListeners: 1
Registry: https://index.docker.io/v1/
Labels:
Experimental: false
Insecure Registries:
 127.0.0.0/8
Live Restore Enabled: false
Product License: Community Engine

有没有人有解决问题的想法？

附言对不起我的英语不好。

Answer 1

version: '3'
services:
  test-environment:
    image: alpine:3.9
    environment:
      VAR1: 'variable 1'
      VAR2: '222'
    command: '/bin/sh -c "echo $$VAR1 $$VAR2"'

要点:

variable-substitution

docker inspect命令检查是否已为该容器正确配置env变量。

我使用版本3，因为我的docker-compose不支持您使用的版本。

.env文件功能仅在您使用docker-compose up命令时有效，而不适用于docker stack deploy。

当您的配置需要文字美元符号时，可以使用$$(美元符号)。这也可以防止Compose插值，因此$$可以让您引用您不想由Compose处理的环境变量。

如果您忘记并使用一个美元符号($)，Compose会将值解释为环境变量并警告您:

WARNING: The VAR1 variable is not set. Defaulting to a blank string. WARNING: The VAR2 variable is not set. Defaulting to a blank string.