Dockerfile:如何从文件内容设置环境变量 [英] Dockerfile: how to set env variable from file contents
问题描述
我想在Dockerfile中设置一个环境变量.
I want to set an environment variable in my Dockerfile.
我有一个.env文件，看起来像这样:
FOO=bar.
I've got a .env file that looks like this:
FOO=bar.
在我的Dockerfile中，我有一个命令来解析该文件的内容并将其分配给FOO.
Inside my Dockerfile, I've got a command that parses the contents of that file and assigns it to FOO.
RUN 'export FOO=$(echo "$(cut -d'=' -f2 <<< $(grep FOO .env))")'
我遇到的问题是上面的脚本没有返回我需要的内容.实际上，它什么也不会返回.
The problem I'm running into is that the script above doesn't return what I need it to. In fact, it doesn't return anything.
当我运行docker-compose up --build时，它失败并显示此错误.
When I run docker-compose up --build, it fails with this error.
The command '/bin/sh -c 'export FOO=$(echo "$(cut -d'=' -f2 <<< $(grep FOO .env))")'' returned a non-zero code: 127
我知道命令/bin/sh -c 'echo "$(cut -d'=' -f2 <<< $(grep FOO .env))"'会生成正确的输出，但是我不知道如何将输出分配给环境变量.
I know that the command /bin/sh -c 'echo "$(cut -d'=' -f2 <<< $(grep FOO .env))"' will generate the correct output, but I can't figure out how to assign that output to an environment variable.
关于我在做什么错的任何建议?
Any suggestions on what I'm doing wrong?
推荐答案
环境变量
如果要在Docker映像中设置许多环境变量(以在容器内使用)，则可以简单地在docker-compose.yml文件中使用env_file配置选项.使用该选项，.env文件中的所有条目都将被设置为映像中的环境变量，因此将被设置为容器.
Environment Variables
If you want to set a number of environment variables into your docker image (to be used within the containers) you can simply use env_file configuration option in your docker-compose.yml file. With that option, all the entries in the .env file will be set as the environment variables in image and hence into containers.
如果您的要求是仅在Dockerfile中使用某些变量，则可以按以下方式指定它们
If your requirement is to use some variables only within your Dockerfile then you specify them as below
ARG FOO
ARG FOO1
ARG FOO2
等等...
ARG FOO
ARG FOO1
ARG FOO2
etc...
并且您必须在docker-compose.yml
build:
context: .
args:
FOO: BAR
FOO1: BAR1
FOO2: BAR2
build:
context: .
args:
FOO: BAR
FOO1: BAR1
FOO2: BAR2
如果您正在考虑将某些值从.env传递到docker-compose文件中，则只需将.env文件放置在与docker-compose.yml文件相同的位置，即可设置以下配置值；
If you are looking into passing some values into your docker-compose file from the .env then you can simply put your .env file same location as the docker-compose.yml file and you can set the configuration values as below;
ports:
- "${HOST_PORT}:80"
因此，作为示例，您可以通过在.env文件中设置服务来设置服务的主机端口
ports:
- "${HOST_PORT}:80"
So, as an example you can set the host port for the service by setting it in your .env file
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