Docker参数为RUN echo命令 [英] Docker argument to a RUN echo command

问题描述

作为Dockerfile的一部分，我试图修改文本文件（ssh_config）以包含用户（作为ARG）在构建时传递给Docker容器的变量。

As part of a Dockerfile, I am attempting to modify a text file (ssh_config) to contain a variable passed through by the user (as an ARG) to the docker container at build time.

在我的Dockerfile中（不是整个文件）：

In my Dockerfile I have (this is not the entire file):

ARG key_name
RUN echo 'Host geoserver\n\
User user\n\
HostName 38.191.191.111\n\
IdentityFile /root/$key_name' >> /etc/ssh/ssh_config

这将收集参数key_name，然后将一些文本附加到ssh_config文本中

This collects the argument key_name, and then appends some text to the ssh_config text file.

运行如下：

docker build --build-arg key_name=GC -t pyramid .

当我检查看写了什么内容时，尚未解析key_name变量，而是已被写为文本（也就是$ key_name）。显然，我希望将其替换为通过ARG传递的变量。

When I check to see what has been written, the key_name variable hasn't been parsed, and instead has been written as text (so literally as $key_name). Obviously I want it to be replaced with the variable passed through ARG.

我尝试使用 $ {key_file} 而不只是 $ key_file ，我在文本文件中得到的是相同的文本，但包括花括号。

I have tried using ${key_file} instead of just $key_file, I just get the same text in the text file but with curly braces included.

所以我的问题是，如何在RUN echo语句中正确使用ARG变量？

So my question is, how can I use the ARG variable correctly within the RUN echo statement?

推荐答案

首先：请确保您的 ARG 在您的 FROM 之后出现。请参阅： https：//docs.docker。 com / engine / reference / builder /＃understand-how-arg-and-from-interact

First: Make sure, your ARG comes after your FROM. See: https://docs.docker.com/engine/reference/builder/#understand-how-arg-and-from-interact

第二个：正如您在此处看到的那样，变量不会在内解释。 ，因此请使用 。

Second: As you can see here, variables won't be interpretad inside '', so use "" instead.

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