如何读取Dockerfile中的Powershell变量？

Question

我正在为 Windows 镜像构建 Docker Desktop。我尝试将变量传递给 Powershell 命令，但它不起作用。

Dockerfile

# escape=`
FROM microsoft/windowsservercore

SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

RUN $someVar="2.60.3" ; echo $someVar

Docker 构建

Sending build context to Docker daemon  2.048kB
Step 1/3 : FROM microsoft/windowsservercore
 ---> 2c42a1b4dea8
Step 2/3 : SHELL powershell -Command $ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';
 ---> Using cache
 ---> ebd40122e316
Step 3/3 : RUN $someVar="2.60.3" ; echo $someVar
 ---> Running in dd28b74bdbda
 ---> 94e17242f6da
Removing intermediate container dd28b74bdbda
Successfully built 94e17242f6da
Successfully tagged secrets:latest

预期结果

我可以通过使用 ENV 变量以及可能的多阶段构建来解决此问题，以避免保留此变量：

# escape=`
FROM microsoft/windowsservercore

SHELL ["powershell", "-Command", "$ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';"]

ENV someVar="2.60.3" 
RUN echo $env:someVar

Sending build context to Docker daemon  2.048kB
Step 1/4 : FROM microsoft/windowsservercore
 ---> 2c42a1b4dea8
Step 2/4 : SHELL powershell -Command $ErrorActionPreference = 'Stop'; $ProgressPreference = 'SilentlyContinue';
 ---> Using cache
 ---> ebd40122e316
Step 3/4 : ENV someVar "2.60.3"
 ---> Running in 8ac10815ff6d
 ---> 9073ec3256e0
Removing intermediate container 8ac10815ff6d
Step 4/4 : RUN echo $env:someVar
 ---> Running in 43a41df36f92
2.60.3
 ---> 09e48901bea9
Removing intermediate container 43a41df36f92
Successfully built 09e48901bea9
Successfully tagged secrets:latest

Answer 1

双引号需要转义才能按预期工作，如下所示someVar=\"2.60.3\"。