如何从docker容器中的文件在dockerfile中设置系统范围的环境变量? [英] How to set system-wide environment variables in dockerfile from a file inside the docker container?

问题描述

我正在将交叉编译环境设置为docker容器.在构建过程中，我为嵌入式设备安装了一个SDK:

I am setting up a cross-compile environment as a docker container. During the build process I install a SDK for an embedded device:

ADD sdk.tar /opt
WORKDIR /opt/
RUN sdkinstall.sh

将sdk安装在文件夹/opt/sdk/

which installs the sdk in a folder /opt/sdk/

现在我有一个文件/opt/sdk/envsetup，其中包含一些环境变量:

Now I have a file /opt/sdk/envsetup that contains some environment variables:

export SDKTARGETSYSROOT=/opt/sdk/sysroots/cortexa9hf-vfp-neon-gad-linux-gnueabi
export PATH=/opt/sdk/sysroots/x86_64-gadsdk-linux/usr/bin:/opt/sdk/sysroots/x86_64-gadsdk-linux/usr/bin/arm-gad-linux-gnueabi:$PATH
export PKG_CONFIG_SYSROOT_DIR=$SDKTARGETSYSROOT

.... and so on

通常，当我在容器中运行shell时，我会执行source /opt/sdk/envsetup，然后从shell中编译内容.

Usually, when I would run a shell in the container I would do source /opt/sdk/envsetup and then compile stuff from the shell.

但是，我想要实现的是所有这些环境变量都存在于docker容器内的系统范围内，并且当我执行诸如docker run -it xyz:latest make <somedir>

However, what I am trying to achieve is that all those environment variables are present system wide inside the docker container and are taken into account when I for example do something like docker run -it xyz:latest make <somedir>

我正在通过调用docker run -it xyz:latest echo $SDKTARGETSYSROOT对此进行测试，并且希望该容器打印/opt/sdk/sysroots/cortexa9hf-vfp-neon-gad-linux-gnueabi`

I am testing this by calling docker run -it xyz:latest echo $SDKTARGETSYSROOT and I was expecting the container to print /opt/sdk/sysroots/cortexa9hf-vfp-neon-gad-linux-gnueabi`

到目前为止我试图实现的目标:

What I tried to achieve this so far:

• 将var添加到/etc/environment:RUN cat /opt/sdk/environment-setup-cortexa9hf-vfp-neon-gad-linux-gnueabi | cut -d" " -f 2 >> /etc/environment
• 将var添加到/etc/profile、/root/.profile和/root/.bashrc:RUN echo -e "# Auto source some variables\nsource /opt/sdk/environment-setup-cortexa9hf-vfp-neon-gad-linux-gnueabi" >> [...]
• 通过ENV SDKTARGETSYSROOT /opt/sdk/sysroots/cortexa9hf-vfp-neon-gad-linux-gnueabi在dockerfile中手动添加一个变量，只是为了测试行为
• .或/bin/bash -c 'source'文件/opt/sdk/envsetup

• Adding the vars to /etc/environment: RUN cat /opt/sdk/environment-setup-cortexa9hf-vfp-neon-gad-linux-gnueabi | cut -d" " -f 2 >> /etc/environment
• Adding the vars to /etc/profile, /root/.profile and /root/.bashrc: RUN echo -e "# Auto source some variables\nsource /opt/sdk/environment-setup-cortexa9hf-vfp-neon-gad-linux-gnueabi" >> [...]
• Adding one var manually in the dockerfile via ENV SDKTARGETSYSROOT /opt/sdk/sysroots/cortexa9hf-vfp-neon-gad-linux-gnueabi, just to test the behaviour
• . or /bin/bash -c 'source' the file /opt/sdk/envsetup

没有一个导致我的预期结果.如何实现这些变量的正确设置?

neither of those led to my expected result. How can I achieve those variables get setup properly?

由于包含变量的文件在docker build的开头是未知的，并且是在容器内部的sdk安装期间创建的，因此，我不太喜欢通过ENV手动将其内容添加到dockerfile中的想法，即使这行得通，也没有.

As the file that contains the variables is unknown at the beginning of the docker build and gets created during the sdk installation inside of the container, I do not really like the idea of adding its content manually into the dockerfile via ENV, even if that worked, which did not.

推荐答案

运行此命令时:

docker run -it xyz:latest echo $SDKTARGETSYSROOT

$SDKTARGETSYSROOT由您的 local 外壳扩展.在任何情况下，您都没有真正在容器内测试环境变量.这将起作用:

The $SDKTARGETSYSROOT is expanded by your local shell. In no case were you actually testing environment variables inside of your container. This would work:

docker run -it xyz:latest sh -c 'echo $SDKTARGETSYSROOT'

单引号禁止在本地shell中进行变量扩展，并且我们需要显式调用sh -c ...，因为Docker默认情况下不使用shell执行命令.比较:

The single quotes inhibit variable expansion in your local shell, and we need to explicitly call sh -c ... because Docker does not, by default, execute commands using a shell. Compare:

$ docker run -it alpine echo $HOME
/home/lars

使用:

$ docker run -it alpine echo '$HOME'
$HOME

使用:

$ docker run -it alpine sh -c 'echo $HOME'
/root

否则，您的几种方法似乎是完成您想要的事情的合理方法.

Otherwise, several of your approaches look like a reasonable way to do what you want.

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