我有一个Dockerfile，我正在一起安装一个香草python环境(我将在其中安装一个应用程序，但在晚些时候)。
FROM ubuntu:12.04
# required to build certain python libraries
RUN apt-get install python-dev -y
# install pip - canonical installation instructions from pip-installer.org
# http://www.pip-installer.org/en/latest/installing.html
ADD https://bitbucket.org/pypa/setuptools/raw/bootstrap/ez_setup.py /tmp/ez_setup.py
ADD https://raw.github.com/pypa/pip/master/contrib/get-pip.py /tmp/get-pip.py
RUN python /tmp/ez_setup.py
RUN python /tmp/get-pip.py
RUN pip install --upgrade pip
# install and configure virtualenv
RUN pip install virtualenv
RUN pip install virtualenvwrapper
ENV WORKON_HOME ~/.virtualenvs
RUN mkdir -p $WORKON_HOME
RUN source /usr/local/bin/virtualenvwrapper.sh
构建运行正常，直到最后一行，在那里我得到以下异常:
[previous steps 1-9 removed for clarity]
...
Successfully installed virtualenvwrapper virtualenv-clone stevedore
Cleaning up...
---> 1fc253a8f860
Step 10 : ENV WORKON_HOME ~/.virtualenvs
---> Running in 8b0145d2c80d
---> 0f91a5d96013
Step 11 : RUN mkdir -p $WORKON_HOME
---> Running in 9d2552712ddf
---> 3a87364c7b45
Step 12 : RUN source /usr/local/bin/virtualenvwrapper.sh
---> Running in c13a187261ec
/bin/sh: 1: source: not found
如果我进入该目录(只是为了测试之前的步骤是否已提交)，我可以看到文件如预期的那样存在:
$ docker run 3a87 ls /usr/local/bin
easy_install
easy_install-2.7
pip
pip-2.7
virtualenv
virtualenv-2.7
virtualenv-clone
virtualenvwrapper.sh
virtualenvwrapper_lazy.sh
如果我试着运行源代码命令，我得到相同的'not found'错误如上所示。如果我运行一个交互式shell会话，但是，源确实工作:
$ docker run 3a87 bash
source
bash: line 1: source: filename argument required
source: usage: source filename [arguments]
我可以从这里运行脚本，然后愉快地访问workon, mkvirtualenv等。
我做了一些研究，最初看起来问题可能在于bash作为Ubuntu登录shell，而dash作为Ubuntu系统shell, dash不支持源命令。
然而，这个问题的答案似乎是使用'。'而不是source，但这只会导致Docker运行时爆发一个go panic异常。
从Dockerfile run指令运行shell脚本来解决这个问题的最好方法是什么(我运行Ubuntu 12.04 LTS的默认基本映像)。
如果您使用的是Docker 1.12或更新版本，只需使用SHELL !
简短的回答:
一般:
SHELL ["/bin/bash", "-c"]
对于python vituralenv:
SHELL ["/bin/bash", "-c", "source /usr/local/bin/virtualenvwrapper.sh"]
长一点的回答:
从https://docs.docker.com/engine/reference/builder/壳
SHELL ["executable", "parameters"]
The SHELL instruction allows the default shell used for the shell form
of commands to be overridden. The default shell on Linux is
["/bin/sh", "-c"], and on Windows is ["cmd", "/S", "/C"]. The SHELL
instruction must be written in JSON form in a Dockerfile.
The SHELL instruction is particularly useful on Windows where there
are two commonly used and quite different native shells: cmd and
powershell, as well as alternate shells available including sh.
The SHELL instruction can appear multiple times. Each SHELL
instruction overrides all previous SHELL instructions, and affects all
subsequent instructions. For example:
FROM microsoft/windowsservercore
# Executed as cmd /S /C echo default
RUN echo default
# Executed as cmd /S /C powershell -command Write-Host default
RUN powershell -command Write-Host default
# Executed as powershell -command Write-Host hello
SHELL ["powershell", "-command"]
RUN Write-Host hello
# Executed as cmd /S /C echo hello
SHELL ["cmd", "/S"", "/C"]
RUN echo hello
The following instructions can be affected by the SHELL instruction
when the shell form of them is used in a Dockerfile: RUN, CMD and
ENTRYPOINT.
The following example is a common pattern found on Windows which can
be streamlined by using the SHELL instruction:
...
RUN powershell -command Execute-MyCmdlet -param1 "c:\foo.txt"
...
The command invoked by docker will be:
cmd /S /C powershell -command Execute-MyCmdlet -param1 "c:\foo.txt"
This is inefficient for two reasons. First, there is an un-necessary
cmd.exe command processor (aka shell) being invoked. Second, each RUN
instruction in the shell form requires an extra powershell -command
prefixing the command.
To make this more efficient, one of two mechanisms can be employed.
One is to use the JSON form of the RUN command such as:
...
RUN ["powershell", "-command", "Execute-MyCmdlet", "-param1 \"c:\\foo.txt\""]
...
While the JSON form is unambiguous and does not use the un-necessary
cmd.exe, it does require more verbosity through double-quoting and
escaping. The alternate mechanism is to use the SHELL instruction and
the shell form, making a more natural syntax for Windows users,
especially when combined with the escape parser directive:
# escape=`
FROM microsoft/nanoserver
SHELL ["powershell","-command"]
RUN New-Item -ItemType Directory C:\Example
ADD Execute-MyCmdlet.ps1 c:\example\
RUN c:\example\Execute-MyCmdlet -sample 'hello world'
Resulting in:
PS E:\docker\build\shell> docker build -t shell .
Sending build context to Docker daemon 4.096 kB
Step 1/5 : FROM microsoft/nanoserver
---> 22738ff49c6d
Step 2/5 : SHELL powershell -command
---> Running in 6fcdb6855ae2
---> 6331462d4300
Removing intermediate container 6fcdb6855ae2
Step 3/5 : RUN New-Item -ItemType Directory C:\Example
---> Running in d0eef8386e97
Directory: C:\
Mode LastWriteTime Length Name
---- ------------- ------ ----
d----- 10/28/2016 11:26 AM Example
---> 3f2fbf1395d9
Removing intermediate container d0eef8386e97
Step 4/5 : ADD Execute-MyCmdlet.ps1 c:\example\
---> a955b2621c31
Removing intermediate container b825593d39fc
Step 5/5 : RUN c:\example\Execute-MyCmdlet 'hello world'
---> Running in be6d8e63fe75
hello world
---> 8e559e9bf424
Removing intermediate container be6d8e63fe75
Successfully built 8e559e9bf424
PS E:\docker\build\shell>
The SHELL instruction could also be used to modify the way in which a
shell operates. For example, using SHELL cmd /S /C /V:ON|OFF on
Windows, delayed environment variable expansion semantics could be
modified.
The SHELL instruction can also be used on Linux should an alternate
shell be required such as zsh, csh, tcsh and others.
The SHELL feature was added in Docker 1.12.
