我目前有两个相同的Dockerfile，除了开头的一些ENV变量具有不同的值。我想将它们组合到一个Dockerfile中，然后根据一个build-arg / ARG选择ENV变量。
我用$ target或WIN或UNIX尝试过这样的事情:
FROM alpine
ARG target
ARG VAR1_WIN=Value4Win
ARG VAR1_UNIX=Value4Unix
ARG VAR1=VAR1_$target
ARG VAR1=${!VAR1}
RUN echo $VAR1
但这会引发错误:
failed to process "${!VAR1}": missing ':' in substitution我做了很多尝试，但无法将$VAR1扩展一倍。如何正确执行此操作？谢谢。
最佳答案
对于条件语法，可以在多阶段构建中使用一种模式:
# ARG defined before the first FROM can be used in FROM lines
ARG target
# first base image for WIN target
FROM alpine as base-WIN
# switching to ENV since ARG doesn't pass through to the next stage
ENV VAR1=Value4Win
# second base image for UNIX target
FROM alpine as base-UNIX
ENV VAR1=Value4Unix
# select one of the above images based on the value of target
FROM base-${target} as release
RUN echo $VAR1
关于docker - 根据构建ARG在Dockerfile中选择ENV/ARG，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/57516575/