blocks|key|210442|text|添加-e密钥，用于向容器传递环境变量。示例：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|210443|$+MYSQLHOSTIP=$(sudo+docker+inspect+-format="{{+.NetworkSettings.IPAddress+}}"+$MYSQL_CONRAINER_ID)
$+sudo+docker+run+-e+DBIP=$MYSQLHOSTIP+-i+-t+myimage+/bin/bash

root@87f235949a13:/#+echo+$DBIP
172.17.0.2|code-block|syntax|javascript|210444|entityMap^0|2|2|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

add <code>-e</code> key for passing environment variables to container. 
example:

<pre><code>$ MYSQLHOSTIP=$(sudo docker inspect -format="{{ .NetworkSettings.IPAddress }}" $MYSQL_CONRAINER_ID)
$ sudo docker run -e DBIP=$MYSQLHOSTIP -i -t myimage /bin/bash

root@87f235949a13:/# echo $DBIP
172.17.0.2
</code></pre>

blocks|key|210503|text|所以你可以这样做：cat+Dockerfile+%7C+envsubst+%7C+docker+build+-t+my-target+-|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|210504|然后创建一个包含以下内容的Dockerfile：|210505|ENV+MY_ENV_VAR+$MY_ENV_VAR|code-block|syntax|javascript|210506|我猜有些特殊字符可能有问题，但这至少在大多数情况下是有效的。|210507|entityMap^0|9|1J|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|T|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|U|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|V|8|@]|D|@]|E|$]]|$1|O|3|-4|5|6|7|W|8|@]|D|@]|E|$]]]|P|$]]

So you can do:
<code>cat Dockerfile | envsubst | docker build -t my-target -</code>

Then have a Dockerfile with something like:

<pre><code>ENV MY_ENV_VAR $MY_ENV_VAR
</code></pre>

I guess there might be a problem with some special characters, but this works for most cases at least.

blocks|key|210681|text|从运行时创建的文件加载环境变量。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|210682|export+MYVAR="my_var_outside"
cat+>+build/env.sh+<<EOF
MYVAR=${MYVAR}
EOF|code-block|syntax|javascript|210683|..。然后在Dockerfile中|210684|ADD+build+/build
RUN+/build/test.sh|210685|test.sh从env.sh加载MYVAR的位置|210686|#!/bin/bash
.+/build/env.sh
echo+$MYVAR+>+/tmp/testfile|210687|entityMap^0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|U|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Load environment variables from a file you create at runtime.

<pre><code>export MYVAR="my_var_outside"
cat &gt; build/env.sh &lt;&lt;EOF
MYVAR=${MYVAR}
EOF
</code></pre>

... then in the Dockerfile

<pre><code>ADD build /build
RUN /build/test.sh
</code></pre>

where test.sh loads MYVAR from env.sh

<pre><code>#!/bin/bash
. /build/env.sh
echo $MYVAR &gt; /tmp/testfile
</code></pre>

blocks|key|210788|text|在不丧失使用COPY或ADD等命令的能力，并且不使用中间文件的情况下，使用envsubst的另一种方法是使用Bash的Process+Substitution|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|210789|docker+build+-f+<(envsubst+<+Dockerfile)+-t+my-target+.|code-block|syntax|javascript|210790|entityMap|0|LINK|mutability|MUTABLE|url|http://tldp.org/LDP/abs/html/process-sub.html^0|6|4|B|3|11|8|1N|K|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|F|3|G|5|H|7|12|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

An alternative using <code>envsubst</code> without losing the ability to use commands like <code>COPY</code> or <code>ADD</code>, and without using intermediate files would be to use Bash's <a href="http://tldp.org/LDP/abs/html/process-sub.html" rel="nofollow noreferrer" title="Process Sustitution">Process Substitution</a>:

<pre><code>docker build -f &lt;(envsubst &lt; Dockerfile) -t my-target .
</code></pre>

blocks|key|210883|text|如果你只是想找到并替换Dockerfile文件中的所有环境变量($ExampleEnvVar)，然后构建它，这是可行的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|210884|envsubst+<+/path/to/Dockerfile+%7C+docker+build+-t+myDockerImage+.+-f+-|offset|length|style|CODE|210885|entityMap^0|0|0|1X|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

If you just want to find and replace all environment variables ($ExampleEnvVar) in a Dockerfile then build it this would work:

<code>envsubst &lt; /path/to/Dockerfile | docker build -t myDockerImage . -f -</code>

I'm building a container for a ruby app. My app's configuration is contained within environment variables (loaded inside the app with <a href="http://github.com/bkeepers/dotenv">dotenv</a>).

One of those configuration variables is the public ip of the app, which is used internally to make links.
I need to add a dnsmasq entry pointing this ip to 127.0.0.1 inside the container, so it can fetch the app's links as if it were not containerized.

I'm therefore trying to set an <code>ENV</code> in my Dockerfile which would pass an environment variable to the container.

I tried a few things.

<pre><code>ENV REQUEST_DOMAIN $REQUEST_DOMAIN
ENV REQUEST_DOMAIN `REQUEST_DOMAIN`
</code></pre>

Everything passes the "REQUEST_DOMAIN" string instead of the value of the environment variable though.
Is there a way to pass environment variables values from the host machine to the container?

Get environment variable value in Dockerfile

容器

Docker

我正在为一个ruby应用构建一个容器。我的应用程序的配置包含在环境变量中(使用加载到应用程序内部)。其中一个配置变量是应用程序的公共ip，它在内部用于建立链接。我需要添加一个dnsmasq条目，将这个ip指向容器中的127.0.0.1，这样它就可以获取应用程序的链接，就好像它没有被容器化一样。因此，我尝试在Docker...

问获取Dockerfile中的环境变量值
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