在Dockerfile中，如何更新PATH环境变量？

我有一个可以从源代码下载并构建GTK的dockerfile，但是以下行并未更新映像的环境变量：

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

我读到我应该使用ENV来设置环境值，但是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

您可以使用环境更换你Dockerfile如下：

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

尽管Gunter发布的答案是正确的，但与我已经发布的答案没有什么不同。问题不是ENV指令，而是后续指令RUN export $PATH

一旦ENV在Dockerfile中通过声明了环境变量，就无需导出环境变量。

一旦RUN export ...线路被拆除，我的形象被成功建立

不建议这样做（如果要创建/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。