Determine if Python is running inside virtualenv

Question

Is it possible to determine if the current script is running inside a virtualenv environment

User · Answer

To check whether your inside Virtualenv   import os  if os getenv  VIRTUAL ENV        print  Using Virtualenv   else      print  Not using Virtualenv     You can also get more data on your environment   import sys import os  print f Python Executable   sys executable    print f Python Version   sys version    print f Virtualenv   os getenv  VIRTUAL ENV

User · Answer

You can do which python and see if its pointing to the one in virtual env

User · Answer

There are multiple good answers here  and some less robust ones  Here s an overview   How not to do it  Do not rely on on the location of Python or the site-packages folder   If these are set to non-standard locations  that does not mean you re actually in a virtual environment   Users can have more than one Python version installed  and those are not always where you expect them to be   Avoid looking at    sys executable sys prefix pip -V which python   Also  do not check for the presence of venv   venv or envs in any of these paths  This will break for environments with a more unique location  For example  Pipenv uses hash values as the name for its environments   VIRTUAL ENV environment variable  Both virtualenv and venv set the environment variable  VIRTUAL ENV when activating an environment  See PEP 405   You can read out this variable in shell scripts  or use this Python code to determine if it s set   import os running in virtualenv    VIRTUAL ENV  in os environ    alternative ways to write this  also supporting the case where   the variable is set but contains an empty string to indicate    not in a virtual environment   running in virtualenv   bool os environ get  VIRTUAL ENV    running in virtualenv   bool os getenv  VIRTUAL ENV      The problem is  this only works when the environment is activated by the activate shell script   You can start the environment s scripts without activating the environment  so if that is a concern  you have to use a different method   sys base prefix  virtualenv  venv and pyvenv point sys prefix to the Python installed inside of the virtualenv as you would expect   At the same time  the original value of sys prefix is also made available as sys base prefix   We can use that to detect if we re in a virtualenv   import sys   note  Python versions before 3 3 don t have sys base prefix   if you re not in virtual environment running in virtualenv   sys prefix    sys base prefix   Fallback  sys real prefix  Now watch out  virtualenv before version 20 did not set sys base prefix but it set sys real prefix instead   So to be safe  check both as suggested in hroncok s answer   import sys  real prefix   getattr sys   real prefix   None  base prefix   getattr sys   base prefix   sys prefix   running in virtualenv    base prefix or real prefix     sys prefix   Anaconda  If you re using Anaconda virtual environments  check Victoria Stuart s answer

User · Answer

This is an improvement of the accepted answer by Carl Meyer  It works with virtualenv for Python 3 and 2 and also for the venv module in Python 3   import sys   def is venv        return  hasattr sys   real prefix   or              hasattr sys   base prefix   and sys base prefix    sys prefix     The check for sys real prefix covers virtualenv  the equality of non-empty sys base prefix with sys prefix covers venv   Consider a script that uses the function like this   if is venv        print  inside virtualenv or venv   else      print  outside virtualenv or venv     And the following invocation     python2 test py  outside virtualenv or venv    python3 test py  outside virtualenv or venv    python2 -m virtualenv virtualenv2         virtualenv2 bin activate  virtualenv2    python test py  inside virtualenv or venv  virtualenv2    deactivate    python3 -m virtualenv virtualenv3         virtualenv3 bin activate  virtualenv3    python test py  inside virtualenv or venv  virtualenv3    deactivate     python3 -m venv venv3     venv3 bin activate  venv3    python test py  inside virtualenv or venv  venv3    deactivate

User · Answer

Easiest way is to just run  which python  if you are in a virtualenv it will point to its python instead of the global one

User · Answer

A potential solution is   os access sys executable  os W OK    In my case I really just wanted to detect if I could install items with pip as is  While it might not be the right solution for all cases  consider simply checking if you have write permissions for the location of the Python executable   Note  this works in all versions of Python  but also returns True if you run the system Python with sudo  Here s a potential use case   import os  sys can install pip packages   os access sys executable  os W OK   if can install pip packages      import pip     pip main   install    mypackage

User · Answer

Updated Nov 2019  appended       I routinely use several Anaconda-installed virtual environments  venv    This code snippet examples enables you to determine whether or not you are in a venv  or your system environment   and to also require a specific venv for your script   Add to Python script  code snippet      ----------------------------------------------------------------------------   Want script to run in Python 3 5  has required installed OpenCV  imutils      packages   import os    First  see if we are in a conda venv   py27  Python 2 7   py35  Python 3 5   tf  TensorFlow   thee   Theano   try     os environ  CONDA DEFAULT ENV   except KeyError     print   tPlease set the py35   p3   Python 3 5   environment  n      exit      If we are in a conda venv  require the p3 venv  if os environ  CONDA DEFAULT ENV       py35       print   tPlease set the py35   p3   Python 3 5   environment  n       exit      See also    Python  Determine if running inside virtualenv   http   stackoverflow com questions 1871549 python-determine-if-running-inside-virtualenv           SNIP          Example     p2    Anaconda Python 2 7 venv  source activate py27     py27    python  webcam  py     Please set the py35   p3   Python 3 5   environment    py27    p3    Anaconda Python 3 5 venv  source activate py35     py35    python  webcam py -n50      current env  py35     processing  live   found 2 faces and 4 eyes in this frame     threaded OpenCV implementation     num frames  50     webcam -- approx  FPS  18 59     Found 2 faces and 4 eyes   py35      Update 1 -- use in bash scripts   You can also use this approach in bash scripts  e g   those that must run in a specific virtual environment    Example  added to bash script    if    CONDA DEFAULT ENV              lt  lt  note the spaces  important in BASH       then         printf  venv  operating in tf-env  proceed          else         printf  Note  must run this script in tf-env venv          exit fi   Update 2  Nov 2019    For simplicity  I like Matt s answer  https   stackoverflow com a 51245168 1904943     Since my original post I ve moved on from Anaconda venv  and Python itself has evolved viz-a-viz virtual environments    Reexamining this issue  here is some updated Python code that you can insert to test that you are operating in a specific Python virtual environment  venv    import os  re try      if re search  py37   os environ  VIRTUAL ENV             pass except KeyError      print   n tPlease set the Python3 venv  alias  p3   n       exit     Here is some explanatory code    victoria victoria     date  python --version   Thu 14 Nov 2019 11 27 02 AM PST   Python 3 8 0   victoria victoria     python   Python 3 8 0  default  Oct 23 2019  18 51 26      GCC 9 2 0  on linux   Type  help    copyright    credits  or  license  for more information    gt  gt  gt  import os  re   gt  gt  gt  re search  py37   os environ  VIRTUAL ENV     lt re Match object  span  20  24   match  py37  gt    gt  gt  gt  try          if re search  py37   os environ  VIRTUAL ENV               print   n tOperating in Python3 venv  please proceed    -        except KeyError          print   n tPlease set the Python3 venv  alias  p3   n             Please set the Python3 venv  alias  p3     gt  gt  gt   Ctrl-d    now exiting EditableBufferInteractiveConsole      victoria victoria     p3    Python 3 7 venv  source activate py37     py37   victoria victoria     python --version   Python 3 8 0   py37   victoria victoria     env   grep -i virtual   VIRTUAL ENV  home victoria venv py37   py37   victoria victoria     python   Python 3 8 0  default  Oct 23 2019  18 51 26      GCC 9 2 0  on linux   Type  help    copyright    credits  or  license  for more information    gt  gt  gt  import os  re  gt  gt  gt  try          if re search  py37   os environ  VIRTUAL ENV               print   n tOperating in Python3 venv  please proceed    -        except KeyError          print   n tPlease set the Python3 venv  alias  p3   n             Operating in Python3 venv  please proceed    -   gt  gt  gt

User · Answer

It s not bullet-proof but for UNIX environments simple test like  if run  which python3   find  venv      -1        something when not executed from venv   works great for me  It s simpler then testing existing of some attribute and  anyway  you should name your venv directory venv

User · Answer

In windows OS you see something like this    C  Users yourusername virtualEnvName Scripts gt activate  virtualEnvName  C  Users yourusername virtualEnvName Scripts gt    Parentheses mean that you are actually in the virtual environment called  virtualEnvName

User · Answer

Try using pip -V  notice capital V   If you are running the virtual env  it ll show the path to the env  s location

User · Answer

The most reliable way to check for this is to check whether sys prefix    sys base prefix  If they are equal  you are not in a virtual environment  if they are unequal  you are  Inside a virtual environment  sys prefix points to the virtual environment  and sys base prefix is the prefix of the system Python the virtualenv was created from  The above always works for Python 3 stdlib venv and for recent virtualenv  since version 20   Older versions of virtualenv used sys real prefix instead of sys base prefix  and sys real prefix did not exist outside a virtual environment   and in Python 3 3 and earlier sys base prefix did not ever exist  So a fully robust check that handles all of these cases could look like this  import sys  def get base prefix compat         quot  quot  quot Get base real prefix  or sys prefix if there is none  quot  quot  quot      return getattr sys   quot base prefix quot   None  or getattr sys   quot real prefix quot   None  or sys prefix  def in virtualenv        return get base prefix compat      sys prefix  If you only care about supported Python versions and latest virtualenv  you can replace get base prefix compat   with simply sys base prefix  Using the VIRTUAL ENV environment variable is not reliable  It is set by the virtualenv activate shell script  but a virtualenv can be used without activation by directly running an executable from the virtualenv s bin   or Scripts  directory  in which case  VIRTUAL ENV will not be set  Or a non-virtualenv Python binary can be executed directly while a virtualenv is activated in the shell  in which case  VIRTUAL ENV may be set in a Python process that is not actually running in that virtualenv

User · Answer

According to the virtualenv pep at http   www python org dev peps pep-0405  specification you can just use sys prefix instead os environ  VIRTUAL ENV    the sys real prefix does not exist in my virtualenv and same with sys base prefix

User · Answer

Check the  VIRTUAL ENV environment variable   The  VIRTUAL ENV environment variable contains the virtual environment s directory when in an active virtual environment    gt  gt  gt  import os  gt  gt  gt  os environ  VIRTUAL ENV     some path project venv    Once you run deactivate   leave the virtual environment  the  VIRTUAL ENV variable will be cleared empty  Python will raise a KeyError because the environment variable was unset    gt  gt  gt  import os  gt  gt  gt  os environ  VIRTUAL ENV   Traceback  most recent call last     File   lt stdin gt    line 1  in  lt module gt    File   usr local Cellar python 3 7 3 Frameworks Python framework Versions 3 7 lib python3 7 os py   line 678  in   getitem       raise KeyError key  from None KeyError   VIRTUAL ENV    These same environment variable checks can of course also be done outside of the Python script  in the shell

User · Answer

edited  I found that way  what do you think of it    it also returns the venv base path and works even for readthedocs where checking the env variable does not    import os import sys from distutils sysconfig import get config vars   def get venv basedir           Returns the base directory of the virtualenv  useful to read configuration and plugins         exec prefix   get config vars    exec prefix        if hasattr sys   real prefix   is False or exec prefix startswith sys real prefix           raise EnvironmentError  You must be in a virtual environment        return os path abspath get config vars    exec prefix

User · Answer

There are a lot of great methods posted here already  but just adding one more   import site site getsitepackages     tells you where pip installed the packages

User · Answer

This is an old question  but too many examples above are over-complicated   Keep It Simple    in Jupyter Notebook or Python 3 7 1 terminal on Windows 10     import sys print sys executable        example output   gt  gt   C  Anaconda3 envs quantecon python exe   OR     sys base prefix       Example output   gt  gt   C   Anaconda3  envs  quantecon

[python] Determine if Python is running inside virtualenv

Examples related to python

Examples related to virtualenv