Activate a virtualenv with a Python script

Question

I want to activate a virtualenv instance from a Python script   I know it s quite easy to do  but all the examples I ve seen use it to run commands within the env and then close the subprocess   I simply want to activate the virtualenv and return to the shell  the same way that bin activate does   Something like this    me  my-script py -d env-name   env-name me    Is this possible   Relevant   virtualenv     Invoking an env from a script

User · Answer

For python2 3  Using below code snippet we can activate virtual env  activate this    quot  home  lt --path-- gt   lt --virtual env name -- gt  bin activate this py quot   for ubuntu activate this    quot D   lt -- path -- gt   lt --virtual env name -- gt  Scripts  activate this py quot   for windows with open activate this  as f      code   compile f read    activate this   exec       exec code  dict   file   activate this

User · Answer

You should create all your virtualenvs in one folder  such as virt   Assuming your virtualenv folder name is virt  if not change it  cd mkdir custom   Copy the below lines        usr bin env bash ENV PATH   HOME virt  1 bin activate  bash --rcfile  ENV PATH -i   Create a shell script file and paste the above lines     touch custom vhelper nano custom vhelper   Grant executable permission to your file   sudo chmod  x custom vhelper   Now export that custom folder path so that you can find it on the command-line by clicking tab     export PATH  PATH   HOME custom   Now you can use it from anywhere by just typing the below command     vhelper YOUR VIRTUAL ENV FOLDER NAME   Suppose it is abc then     vhelper abc

User · Answer

The simplest solution to run your script under virtualenv s interpreter is to replace the default shebang line with path to your virtualenv s interpreter like so at the beginning of the script      path to project venv bin python   Make the script executable    chmod u x script py   Run the script     script py   Voila

User · Answer

To run another Python environment according to the official Virtualenv documentation  in the command line you can specify the full path to the executable Python binary  just that  no need to active the virtualenv before    path to virtualenv bin python  The same applies if you want to invoke a script from the command line with your virtualenv  You don t need to activate it before  me   path to virtualenv bin python myscript py  The same for a Windows environment  whether it is from the command line or from a script    gt   path to env Scripts python exe myscript py

User · Answer

If you want to run a Python subprocess under the virtualenv  you can do that by running the script using the Python interpreter that lives inside virtualenv s  bin  directory  import subprocess    Path to a Python interpreter that runs any Python script   under the virtualenv  path to virtualenv  python bin    quot  path to virtualenv bin python quot     Path to the script that must run under the virtualenv script file    quot must run under virtualenv script py quot   subprocess Popen  python bin  script file    However  if you want to activate the virtualenv under the current Python interpreter instead of a subprocess  you can use the activate this py script    Doing execfile   on this file will alter the current interpreter s   environment so you can import libraries in the virtualenv activate this file    quot  path to virtualenv bin activate this py quot   execfile activate this file  dict   file   activate this file

User · Answer

The top answer only works for Python nbsp 2 x  For Python 3 x  use this   activate this file     path to virtualenv bin activate this py   exec compile open activate this file   rb   read    activate this file   exec    dict   file   activate this file     Reference  What is an alternative to execfile in Python 3

User · Answer

The child process environment is lost in the moment it ceases to exist  and moving the environment content from there to the parent is somewhat tricky   You probably need to spawn a shell script  you can generate one dynamically to  tmp  which will output the virtualenv environment variables to a file  which you then read in the parent Python process and put in os environ   Or you simply parse the activate script in using for the line in open  bin activate    manually extract stuff  and put in os environ  It is tricky  but not impossible

User · Answer

Just a simple solution that works for me  I don t know why you need the Bash script which basically does a useless step  am I wrong     import os os system   bin bash  --rcfile flask bin activate     Which basically does what you need    hellsing silence Foundation   python2 7 pythonvenv py  flask  hellsing silence Foundation     Then instead of deactivating the virtual environment  just Ctrl   D or exit  Is that a possible solution or isn t that what you wanted

User · Answer

It turns out that  yes  the problem is not simple  but the solution is   First I had to create a shell script to wrap the  source  command  That said I used the     instead  because I ve read that it s better to use it than source for Bash scripts      bin bash    path to env bin activate   Then from my Python script I can simply do this   import os os system   bin bash --rcfile  path to myscript sh     The whole trick lies within the --rcfile argument   When the Python interpreter exits it leaves the current shell in the activated environment   Win

[python] Activate a virtualenv with a Python script

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