在 CMD 中使用环境变量 [英] Use environment variables in CMD

问题描述

我可以在 Dockerfile 的 CMD 节中使用环境变量吗?

Can I use environment variables in my CMD stanza in a Dockerfile?

我想做这样的事情:

CMD ["myserver", "--arg=$ARG", "--memcache=$MEMCACHE_11211_TCP_ADDR:$MEMCACHE_11211_TCP_PORT"]

其中 $MEMCACHE_11211_TCP_* 将通过包含我的 docker run 命令的 --link 参数自动设置.并且 $ARG 可以由用户在运行时配置，也许可以通过-e"参数?

Where $MEMCACHE_11211_TCP_* would be set automatically by the inclusion of the --link parameter of my docker run command. And $ARG would be configurable by the user at runtime, maybe by the "-e" parameter?

这似乎对我不起作用，例如，它似乎是字面上传递字符串$ARG".

This doesn't seem to be working for me, it seems to be literally passing through the string "$ARG" for example.

推荐答案

这个回答可能有点晚了.但是根据您编写参数的方式，CMD 的环境解释略有不同.如果您将 CMD 作为字符串(不在数组内)传递，它会作为 shell 而不是 exec 启动.请参阅 https://docs.docker.com/engine/reference/builder/#cmd.

This answer may be a little late. But environment for CMD is interpreted slightly differently depending on how you write the arguments. If you pass the CMD as a string (not inside an array), it gets launched as a shell instead of exec. See https://docs.docker.com/engine/reference/builder/#cmd.

您可以尝试不带数组语法的 CMD 作为 shell 运行:

You may try the CMD without the array syntax to run as a shell:

CMD myserver --arg=$ARG --memcache=$MEMCACHE_11211_TCP_ADDR:$MEMCACHE_11211_TCP_PORT

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