Docker编写的条件语句?(例如，仅在有条件的情况下添加音量) [英] Docker-compose, conditional statements? (e.g. add volume only if condition)

问题描述

我想将卷添加到我的服务中，但前提是最终用户为其提供了一个文件夹.否则，不应安装任何卷，因为已准备好的映像在默认文件夹中具有有效数据.

I want to add a volume to my service, but only if the final user gave a folder for it. Otherwise, no volume should be mounted, for the already-prepared image has valid data in a default folder.

也就是说，我想做类似(伪代码)的事情:

That is, I want to do something like (pseudocode):

services:

  my_awesome_service:
  
    volumes:
      if ${VARIABLE} => ${VARIABLE}:/app/folder

这样的条件语句是否可以在docker-compose文件中定义?

我看到的使之成为可能的唯一方法是首先定义一个基本的docker-compose文件，该文件没有卷挂载，并且仅在 $ VARIABLE 已定义.对于单个或几个条件，这都很好，但是如果有很多条件，这会令人讨厌.

The only way I see to make this possible is to first define a base docker-compose file, which does not have the volume mount, and the call on a second docker-compose file only if the $VARIABLE is defined. This is fine for a single or few conditions, but gets nasty if there are many.

有解决方案吗?

推荐答案

穷人的解决方案:

    volumes:
      ${VARIABLE:-/dev/null}:/app/folder

或者:

    volumes:
      ${VARIABLE:-/dev/null}:${VARIABLE:-/tmp}/app/folder

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