CMD 中的 Docker ENV

Question

我正在尝试执行以下操作:

将构建参数传递给我的 docker 构建命令

将其作为环境变量存储在我的容器中

在我的 CMD 中使用它以在我的容器启动时启动。

下面是我的设置:

FROM ubuntu:xenial

ARG EXECUTABLE

ENV EXECUTABLE ${EXECUTABLE}


CMD ["/opt/foo/bin/${EXECUTABLE}", "-bar"]

这是我构建容器的方式

    docker build --build-arg EXECUTABLE=$EXECUTABLE  -t test_image .

这是我运行图像的方式

    docker run -d test_image

当我运行容器时它崩溃并告诉我

docker: Error response from daemon: OCI runtime create failed: 
container_linux.go:296: starting container process caused 
"exec: \"/opt/foo/bin/${EXECUTABLE}\": stat /opt/foo/bin/${EXECUTABLE}: 
no such file or directory": unknown.

Answer 1

要使用环境变量，您需要使用 shell。
https://docs.docker.com/engine/reference/builder/#cmd

Note: Unlike the shell form, the exec form does not invoke a command shell. This means that normal shell processing does not happen. For example, CMD [ "echo", "$HOME" ] will not do variable substitution on $HOME. If you want shell processing then either use the shell form or execute a shell directly, for example: CMD [ "sh", "-c", "echo $HOME" ]. When using the exec form and executing a shell directly, as in the case for the shell form, it is the shell that is doing the environment variable expansion, not docker.

基于此，我认为您可以通过以下 Dockerfile 正常工作.

FROM ubuntu:xenial

ARG EXECUTABLE

ENV EXECUTABLE ${EXECUTABLE}

CMD [ "sh", "-c", "/opt/foo/bin/${EXECUTABLE}", "-bar"]