在Dockerfile中,如何更新PATH环境变量？

Question

我有一个从源代码下载和构建GTK的dockerfile,但以下行没有更新我的图像的环境变量:

RUN PATH="/opt/gtk/bin:$PATH"
RUN export PATH

我读到我应该使用ENV来设置环境值,但以下指令似乎也不起作用:

ENV PATH /opt/gtk/bin:$PATH

这是我的整个Dockerfile:

FROM ubuntu
RUN apt-get update
RUN apt-get install -y golang gcc make wget git libxml2-utils libwebkit2gtk-3.0-dev libcairo2 libcairo2-dev libcairo-gobject2 shared-mime-info libgdk-pixbuf2.0-* libglib2-* libatk1.0-* libpango1.0-* xserver-xorg xvfb

# Downloading GTKcd
RUN wget http://ftp.gnome.org/pub/gnome/sources/gtk+/3.12/gtk+-3.12.2.tar.xz
RUN tar xf gtk+-3.12.2.tar.xz
RUN cd gtk+-3.12.2

# Setting environment variables before running configure
RUN CPPFLAGS="-I/opt/gtk/include"
RUN LDFLAGS="-L/opt/gtk/lib"
RUN PKG_CONFIG_PATH="/opt/gtk/lib/pkgconfig"
RUN export CPPFLAGS LDFLAGS PKG_CONFIG_PATH
RUN ./configure --prefix=/opt/gtk
RUN make
RUN make install

# running ldconfig after make install so that the newly installed libraries are found.
RUN ldconfig

# Setting the LD_LIBRARY_PATH environment variable so the systems dynamic linker can find the newly installed libraries.
RUN LD_LIBRARY_PATH="/opt/gtk/lib"

# Updating PATH environment program so that utility binaries installed by the various libraries will be found.
RUN PATH="/opt/gtk/bin:$PATH"
RUN export LD_LIBRARY_PATH PATH

# Collecting garbage
RUN rm -rf gtk+-3.12.2.tar.xz

# creating go code root
RUN mkdir gocode
RUN mkdir gocode/src
RUN mkdir gocode/bin
RUN mkdir gocode/pkg

# Setting the GOROOT and GOPATH enviornment variables, any commands created are automatically added to PATH
RUN GOROOT=/usr/lib/go
RUN GOPATH=/root/gocode
RUN PATH=$GOPATH/bin:$PATH
RUN export GOROOT GOPATH PATH

Answer 1

您可以使用环境更换你Dockerfile如下:

ENV PATH="/opt/gtk/bin:${PATH}"

Answer 2

虽然Gunter发布的答案是正确的,但它与我已发布的内容没有什么不同.问题不是ENV指令,而是后续指令RUN export $PATH

一旦ENV在Dockerfile中声明了环境变量,就无需导出环境变量.

一旦RUN export ...删除线条,我的图像就会成功构建

Answer 3

[我在回复所选答案时提到了这一点，但建议使其更加突出作为自己的答案]

应该注意的是

ENV PATH="/opt/gtk/bin:${PATH}" 

可能不一样

ENV PATH="/opt/gtk/bin:$PATH" 

前者带有大括号，可能会为您提供主机的 PATH。文档并未暗示会是这种情况，但我观察到确实如此。这很容易检查只是做RUN echo $PATH并将其与RUN echo ${PATH}

Answer 4

不鼓励这样做（如果您想创建/分发干净的 Docker 映像），因为该PATH变量是由/etc/profile脚本设置的，因此可以覆盖该值。

head /etc/profile：

if [ "`id -u`" -eq 0 ]; then
  PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
else
  PATH="/usr/local/bin:/usr/bin:/bin:/usr/local/games:/usr/games"
fi
export PATH

在 Dockerfile 的末尾，您可以添加：

RUN echo "export PATH=$PATH" > /etc/environment

因此为所有用户设置了 PATH。