I'm attempting to find a set of steps necessary to make a virtual environment of python 3.6 on windows relocatable.
1st I created a virtual environment on virtualenv 15.1.0 with the following command:
virtualenv
--always-copy
-a "path\to\project\dir"
-r "path\to\requirements.txt"
venv_name
After this, I run the following command to use the built in 'make paths relative ' functionality of virtualenv:
virtualenv --relocatable venv_name
Part of my requirements.txt is pypiwin32 library which, at least when installed via pip, wont work until the:
python Scripts/pywin32_postinstall.py -install
script is run (See here for details).
At this point, if I search the venv directory for clues of hardcoding, I see them in scripts\activate.bat, which I can make relative by changing this:
set "VIRTUAL_ENV=C:\path\to\venv"
into this:
pushd %~dp0..
set VIRTUAL_ENV=%CD%
popd
There are some other other places where I had to make slight adjustments to make them relative (I used the search in folder feature of sublime with my username as the search parameter - it brought up all the path\to\username\then\some\more style lines in the directory.
There are 2 hardcoded paths which are not so simple:
1. "path\to\venv\Lib\orig-prefix.txt"
I understand that orig-prefix.txt is a record of which is the source python installation on which the venv was based and so cannot really be relative but may need to be left blank if moving the venv to another machine (it's absence may crash the python launcher but its emptiness is fine.)
2. "path\to\venv\Lib\site-packages\virtualenv_path_extensions.pth"
This is trickier. As it is a hard-coded path which is then added to sys.path as a location to look for modules, when I move the venv to another machine where this path doesn't exist, the module load will fail.
Is there a way I can add relative paths to the configuration files such as virtualenv_path_extensions.pth
Normally environments are tied to a specific path. That means that you cannot move an environment around or copy it to another computer. You can fix up an environment to make it relocatable with the command:
$ virtualenv --relocatable ENV
This will make some of the files created by setuptools use relative paths, and will change all the scripts to use activate_this.py instead of using the location of the Python interpreter to select the environment.
Note: scripts which have been made relocatable will only work if the virtualenv is activated, specifically the python executable from the virtualenv must be the first one on the system PATH. Also note that the activate scripts are not currently made relocatable by virtualenv --relocatable.
Note: you must run this after you’ve installed any packages into the environment. If you make an environment relocatable, then install a new package, you must run virtualenv --relocatable again.
Also, this does not make your packages cross-platform. You can move the directory around, but it can only be used on other similar computers. Some known environmental differences that can cause incompatibilities: a different version of Python, when one platform uses UCS2 for its internal unicode representation and another uses UCS4 (a compile-time option), obvious platform changes like Windows vs. Linux, or Intel vs. ARM, and if you have libraries that bind to C libraries on the system, if those C libraries are located somewhere different (either different versions, or a different filesystem layout).
I have downloaded a python package to install, on my ubuntu machine. The package has already a setup.py file to use, but I want to change the default python installation address to something else, for this package specifically (and not for good). So what I tried is:
First in the terminal, I export that address of the new folder:
export PYTHONPATH=${PYTHONPATH}:${HOME}/Documents/testfolder/lib/python2.7/site-packages
Then I add this exported address as prefix to the installation command:
python setup.py install --prefix=~/Documents/testfolder
The installation goes through. Now to make python always look for this new path as well (next to the default installation path), I export the address in bashrc file:
export PYTHONPATH="${PYTHONPATH}:~/Documents/testfolder/lib/python2.7/site-packages"
But now whenever I open a terminal and try to import the installed package, it cannot see ("no module named..."). Only when I open a terminal in the folder where I had the installation files (namely setup.py), and run python, can it then see the package, and it works there.
Why isn't my export in bashrc making the package available from anywhere?
Is there something I have done wrong in the above?
To answer your question about the export path. Do you have $PYTHONPATH as a part of your $PATH? If not you should add it to path.
The best way to handle this scenario in my opinion is to use a virtual python environment. There are a couple to choose from, but I like virtualenv the best. The reason to take this approach is because you can manage different versions of python in separate folders. And have separate packages installed in these folders. I recommend looking into it as it is a very useful tool. If you want an examole of how to use it i can provide that https://virtualenv.pypa.io/en/stable/
Trying to install python from the link here does not seem to give access to the python command in Msysgit... following the instructions here, does not actually say how to get python to work as needed.
Current error when running parse new project_name is:
/bin/env: python: No such file or directory
I believe it's likely because it installed it at C:\Python... anyone know how to fix this?
This error means that Git Bash does not know where your python.exe is. It searches your normal windows search path, the PATH environment variable. You're probably failing the 4th step on the instructions already "Make sure Python is working in the Git Bash":
$ python --version
sh.exe: python: command not found
To fix that, append C:\Python (or wherever you installed python) to your PATH environment variable in windows (instructions here). You need to restart the bash after this for the change to take effect. This will allow you to run python from the windows command prompt as well.
C:\> python --version
Python 2.7.2
If you don't want to alter your windows PATH variable or make python only available to git bash, you could create a .bashrc file in your %USERPROFILE% directory and set the variable there:
C:\>notepad %USERPROFILE%\.bashrc
and add
export PATH=/c/Python:$PATH
to the file. That script is executed every time you start the git bash and prepends C:\Python to git bash's PATH variable, leaving the system-wide PATH variable untouched.
Now that you know what has to be done, you can use this shortcut on the bash instead (appends the export command to your .bashrc)
$ echo export PATH=/c/Python:\$PATH >> ~/.bashrc
Hmmm. If you're using Python 2.7 like the instructions say to, you could try instead of that doing "C:/Python27/python.exe" insted of "python".
I think you can add the location of the python.exe in the PATH environment variable. Follow the steps: Go to My Computer->Right click->Properties->Advanced System Settings->Click Environmental Variables. Now click PATH and then click EDIT. In the variable value field, go to the end and append ';' (without quotes) and then add the absolute path of the .exe file which you want to run via Git-Bash.
don't know if this could be your issue, but its always worth a check.
check your python path is set correctly?
computer->properties->advanced system settings-> environment variables->system variables->PYTHONPATH, value = C:\PYTHON20;C:\PYTHON20\DLLS;C:\PYTHON20\LIB;C:\PY THON20\LIB\LIB-TK
I have been programming in Python for a while now, and have created some utilities that I use a lot. Whenever I start a new project, I start writing, and as I need these utilities I copy them from where ever I think the latest version of the particular utility is. I have enough projects now that I am losing track of where the latest version is. And, I will upgrade one of these scripts to fix a problem in a specific situation, and then wish it had propagated back to all of the other projects that use that script.
I am thinking the best way to solve this problem is to create a directory in the site-packages directory, and put all of my utility modules in there. And then add this directory to the sys.path directory list.
Is this the best way to solve this problem?
How do modify my installation of Python so that this directory is always added to sys.path, and I don't have to explicitly modify sys.path at the beginning of each module that needs to use these utilities?
I'm using Python 2.5 on Windows XP, and Wing IDE.
The site-packages directory within the Python lib directory should always be added to sys.path, so you shouldn't need to modify anything to take care of that. That's actually just what I'd recommend, that you make yourself a Python package within that directory and put your code in there.
Actually, something you might consider is packaging up your utilities using distutils. All that entails is basically creating a setup.py file in the root of the folder tree where you keep your utility code. The distutils documentation that I just linked to describes what should go in setup.py. Then, from within that directory, run
python setup.py install
to install your utility code into the system site-packages directory, creating the necessary folder structure automatically. Or you can use
python setup.py install --user
to install it into a site-packages folder in your own user account.
Add your directory to the PYTHONPATH environment variable. For windows, see these directions.
If it's not in site-packages then you can add a file with the extension .pth to your site-packages directory.
The file should have one path per line, that you want included in sys.path
Whenever I use sys.path.append, the new directory will be added. However, once I close python, the list will revert to the previous (default?) values. How do I permanently add a directory to PYTHONPATH?
If you're using bash (on a Mac or GNU/Linux distro), add this to your ~/.bashrc
export PYTHONPATH="${PYTHONPATH}:/my/other/path"
You need to add your new directory to the environment variable PYTHONPATH, separated by a colon from previous contents thereof. In any form of Unix, you can do that in a startup script appropriate to whatever shell you're using (.profile or whatever, depending on your favorite shell) with a command which, again, depends on the shell in question; in Windows, you can do it through the system GUI for the purpose.
superuser.com may be a better place to ask further, i.e. for more details if you need specifics about how to enrich an environment variable in your chosen platform and shell, since it's not really a programming question per se.
Instead of manipulating PYTHONPATH you can also create a path configuration file. First find out in which directory Python searches for this information:
python -m site --user-site
For some reason this doesn't seem to work in Python 2.7. There you can use:
python -c 'import site; site._script()' --user-site
Then create a .pth file in that directory containing the path you want to add (create the directory if it doesn't exist).
For example:
# find directory
SITEDIR=$(python -m site --user-site)
# create if it doesn't exist
mkdir -p "$SITEDIR"
# create new .pth file with our path
echo "$HOME/foo/bar" > "$SITEDIR/somelib.pth"
This works on Windows
On Windows, with Python 2.7 go to the Python setup folder.
Open Lib/site-packages.
Add an example.pth empty file to this folder.
Add the required path to the file, one per each line.
Then you'll be able to see all modules within those paths from your scripts.
In case anyone is still confused - if you are on a Mac, do the following:
Open up Terminal
Type open .bash_profile
In the text file that pops up, add this line at the end:
export PYTHONPATH=$PYTHONPATH:foo/bar
Save the file, restart the Terminal, and you're done
You could add the path via your pythonrc file, which defaults to ~/.pythonrc on linux. ie.
import sys
sys.path.append('/path/to/dir')
You could also set the PYTHONPATH environment variable, in a global rc file, such ~/.profile on mac or linux, or via Control Panel -> System -> Advanced tab -> Environment Variables on windows.
To give a bit more explanation, Python will automatically construct its search paths (as mentioned above and here) using the site.py script (typically located in sys.prefix + lib/python<version>/site-packages as well as lib/site-python). One can obtain the value of sys.prefix:
python -c 'import sys; print(sys.prefix)'
The site.py script then adds a number of directories, dependent upon the platform, such as /usr/{lib,share}/python<version>/dist-packages, /usr/local/lib/python<version>/dist-packages to the search path and also searches these paths for <package>.pth config files which contain specific additional search paths. For example easy-install maintains its collection of installed packages which are added to a system specific file e.g on Ubuntu it's /usr/local/lib/python2.7/dist-packages/easy-install.pth. On a typical system there are a bunch of these .pth files around which can explain some unexpected paths in sys.path:
python -c 'import sys; print(sys.path)'
So one can create a .pth file and put in any of these directories (including the sitedir as mentioned above). This seems to be the way most packages get added to the sys.path as opposed to using the PYTHONPATH.
Note: On OSX there's a special additional search path added by site.py for 'framework builds' (but seems to work for normal command line use of python): /Library/Python/<version>/site-packages (e.g. for Python2.7: /Library/Python/2.7/site-packages/) which is where 3rd party packages are supposed to be installed (see the README in that dir). So one can add a path configuration file in there containing additional search paths e.g. create a file called /Library/Python/2.7/site-packages/pip-usr-local.pth which contains /usr/local/lib/python2.7/site-packages/ and then the system python will add that search path.
On MacOS, Instead of giving path to a specific library. Giving full path to the root project folder in
~/.bash_profile
made my day, for example:
export PYTHONPATH="${PYTHONPATH}:/Users/<myuser>/project_root_folder_path"
after this do:
source ~/.bash_profile
On linux you can create a symbolic link from your package to a directory of the PYTHONPATH without having to deal with the environment variables. Something like:
ln -s /your/path /usr/lib/pymodules/python2.7/
For me it worked when I changed the .bash_profile file. Just changing .bashrc file worked only till I restarted the shell.
For python 2.7 it should look like:
export PYTHONPATH="$PYTHONPATH:/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python"
at the end of the .bash_profile file.
Adding export PYTHONPATH="${PYTHONPATH}:/my/other/path" to the ~/.bashrc might not work if PYTHONPATH does not currently exist (because of the :).
export PYTHONPATH="/my/other/path1"
export PYTHONPATH="${PYTHONPATH}:/my/other/path2"
Adding the above to my ~/.bashrc did the trick for me on Ubuntu 16.04
This is an update to this thread which has some old answers.
For those using MAC-OS Catalina or some newer (>= 10.15), it was introduced a new Terminal named zsh (a substitute to the old bash).
I had some problems with the answers above due to this change, and I somewhat did a workaround by creating the file ~/.zshrc and pasting the file directory to the $PATH and $PYTHONPATH
So, first I did:
nano ~/.zshrc
When the editor opened I pasted the following content:
export PATH="${PATH}:/Users/caio.hc.oliveira/Library/Python/3.7/bin"
export PYTHONPATH="${PYTHONPATH}:/Users/caio.hc.oliveira/Library/Python/3.7/bin"
saved it, and restarted the terminal.
IMPORTANT: The path above is set to my computer's path, you would have to adapt it to your python.
The script below works on all platforms as it's pure Python. It makes use of the pathlib Path, documented here https://docs.python.org/3/library/pathlib.html, to make it work cross-platform. You run it once, restart the kernel and that's it. Inspired by https://medium.com/#arnaud.bertrand/modifying-python-s-search-path-with-pth-files-2a41a4143574. In order to run it it requires administrator privileges since you modify some system files.
from pathlib import Path
to_add=Path(path_of_directory_to_add)
from sys import path
if str(to_add) not in path:
minLen=999999
for index,directory in enumerate(path):
if 'site-packages' in directory and len(directory)<=minLen:
minLen=len(directory)
stpi=index
pathSitePckgs=Path(path[stpi])
with open(str(pathSitePckgs/'current_machine_paths.pth'),'w') as pth_file:
pth_file.write(str(to_add))
Just to add on awesomo's answer, you can also add that line into your ~/.bash_profile or ~/.profile
The add a new path to PYTHONPATH is doing in manually by:
adding the path to your ~/.bashrc profile, in terminal by:
vim ~/.bashrc
paste the following to your profile
export PYTHONPATH="${PYTHONPATH}:/User/johndoe/pythonModule"
then, make sure to source your bashrc profile when ever you run your code in terminal:
source ~/.bashrc
Hope this helps.
I added permanently in Windows Vista, Python 3.5
System > Control Panel > Advanced system settings > Advanced (tap) Environment Variables > System variables > (if you don't see PYTHONPATH in Variable column) (click) New > Variable name: PYTHONPATH > Variable value:
Please, write the directory in the Variable value. It is details of Blue Peppers' answer.
Fix Python Path issues when you switch from bash to zsh
I ran into Python Path problems when I switched to zsh from bash.
The solution was simple, but I failed to notice.
Pip was showing me, that the scripts blah blah or package blah blah is installed in ~/.local/bin which is not in path.
After reading some solutions to this question, I opened my .zshrc to find that the solution already existed.
I had to simply uncomment a line:
Take a look
I found a solution to do this in a anaconda environment here: https://datacomy.com/python/anaconda/add_folder_to_path/
Just:
conda develop /your_path
In Python 3.6.4 you can persist sys.path across python sessions like this:
import sys
import os
print(str(sys.path))
dir_path = os.path.dirname(os.path.realpath(__file__))
print(f"current working dir: {dir_path}")
root_dir = dir_path.replace("/util", '', 1)
print(f"root dir: {root_dir}")
sys.path.insert(0, root_dir)
print(str(sys.path))
I strongly suggest you use virtualenv and virtualenvwrapper otherwise you will clutter your path
Inspired by andrei-deusteanu answer, here is my version. This allows you to create a number of additional paths in your site-packages directory.
import os
# Add paths here. Then Run this block of code once and restart kernel. Paths should now be set.
paths_of_directories_to_add = [r'C:\GIT\project1', r'C:\GIT\project2', r'C:\GIT\project3']
# Find your site-packages directory
pathSitePckgs = os.path.join(os.path.dirname(os.__file__), 'site-packages')
# Write a .pth file in your site-packages directory
pthFile = os.path.join(pathSitePckgs,'current_machine_paths.pth')
with open(pthFile,'w') as pth_file:
pth_file.write('\n'.join(paths_of_directories_to_add))
print(pthFile)
After multiple bashing into wall. Finally resolved, in my CentOS 8 the pip3 was old, which was showing error to install the recent packages.
Now, I had downloaded the Python source package, which is Python-3.10.4 and installed the usual way, however the post-installation check generated errors in bash.
And I could not remove the existing Python, because that would break the CentOS desktop features.
Solution:
For building
./configure //don't not add --prefix=/usr, which you need to set proper care
make -j8
sudo make install
Now, as you have multiple Python installed, you can set alias python=python3
And for setting PYTHONPATH
export PYTHONPATH="/usr/local/bin/python3.10:/usr/local/lib/python3.10/lib-dynload:/usr/local/lib/python3.10/site-packages"
Don't add PYTHONHOME
For those who (like me) don't want to get too deeply involved in Python file management (which seems hopelessly overcomplicated), creating a .pth file works perfectly on my Windows 11 laptop (I'm using Visual Studio Code in Windows). So just go to the folder for your virtual environment site packages - there's mine:
Create a text file with a .pth extension - I called mine wheal.pth:
Add paths to it:
The best thing about this in VS Code is that import statements recognise this path (I had to exit VS Code and go back in), so now more typing # type: ignore to suppress linting warning messages!
on Mac :
user#terminal$ env PYTHONPATH=module_path python3
>>> import sys
>>> sys.path
['module_path', 'plus_other_python3_paths',...]
Shortest path between A <-> B is a straight line;
import sys
if not 'NEW_PATH' in sys.path:
sys.path += ['NEW_PATH']