在 Docker 容器中添加交互式用户输入，例如“read”

Question

我想制作一个可以执行以下操作的 Docker 映像：

1. 获取用户输入并将其存储在本地变量中read
2. 在以后的命令中使用该变量

使用它我有以下 Dockerfile：

FROM ubuntu
RUN ["echo", "'Input something: '"]
RUN ["read", "some_var"]
RUN ["echo", "You wrote $some_var!"]

运行时docker build，会产生以下输出：

Sending build context to Docker daemon  3.072kB
Step 1/4 : FROM ubuntu
 ---> 4e2eef94cd6b
Step 2/4 : RUN ["echo", "'Input something: '"]
 ---> Using cache
 ---> a9d967721ade
Step 3/4 : RUN ["read", "some_var"]
 ---> Running in e1c603e2d376
OCI runtime create failed: container_linux.go:349: starting container process caused "exec: \"read\": executable file not found in $PATH": unknown

read似乎是一个内置的 bash“函数”，因为which read什么也没产生。我["read", "some_var"]用["/bin/bash -c read", "some_var"]and替换["/bin/bash", "-c", "read", "some_var"]，但两者都产生以下结果：

...
Step 3/4 : RUN ["/bin/bash -c read", "some_var"]
 ---> Running in 6036267781a4
OCI runtime create failed: container_linux.go:349: starting container process caused "exec: \"/bin/bash -c read\": stat /bin/bash -c read: no such file or directory": unknown

...
Step 3/4 : RUN ["/bin/bash", "-c", "read", "some_var"]
 ---> Running in 947dda3a9a6c
The command '/bin/bash -c read some_var' returned a non-zero code: 1

此外，我还将其替换为RUN read some_varbut ，结果如下：

...
Step 3/4 : RUN read some_var
 ---> Running in de0444c67386
The command '/bin/sh -c read some_var' returned a non-zero code: 1

谁能帮我这个？

Answer 1

一种解决方案是使用外部 shell 脚本并使用ENTRYPOINT。

内容run.sh：

#!/bin/bash
echo "Input something!"
read some_var
echo "You wrote ${some_var}!"

内容Dockerfile：

FROM ubuntu
COPY "run.sh" .
RUN ["chmod", "+x", "./run.sh"]
ENTRYPOINT [ "./run.sh" ]

这将允许./run.sh在容器旋转时运行：

$ docker build -t test .
Step 1/4 : FROM ubuntu
 ---> 4e2eef94cd6b
Step 2/4 : COPY "run.sh" .
 ---> 37225979730d
Step 3/4 : RUN ["chmod", "+x", "./run.sh"]
 ---> Running in 5f20ded00739
Removing intermediate container 5f20ded00739
 ---> 41174edb932c
Step 4/4 : ENTRYPOINT [ "./run.sh" ]
 ---> Running in bed7717c1242
Removing intermediate container bed7717c1242
 ---> 554da7be7972
Successfully built 554da7be7972
Successfully tagged test:latest

$ docker run -it test
Input something!
Test message 
You wrote Test message!