Python Virtual Environment Shebang for Window and Linux - python

I have a python file that I'd like to execute using the virtual environment (venv) in the same directory as the file. I'd like it to use this venv regardless of whether the user has activated it or not to avoid accidentally running it without the proper environment. I'd like this to work on both Linux and Windows (via Git Bash).
The issue is that venv puts python under the "bin" directory on Linux but under "Scripts" on Windows and I can't seem to find a way to change this behavior when creating it. I tried creating it with Git Bash in hopes that it would "trick" python into using a bin directory instead of Scripts, but that didn't work.
The following shebang works well on Linux:
#!.venv3/bin/python
And this one works well on Windows:
#!.venv3/Scripts/python
But what will work on both? I know that one option would be to create a shell script that activates the environment based on the detected os (using $OSTYPE), but I'd like to avoid this if possible as it isn't otherwise necessary.

You could use the Windows version of the shebang:
#!.venv3/Scripts/python
and then create a symbolic link on the Linux side:
.venv3/Scripts -> .venv3/bin
I just tried this with one of my virtual envs. It worked fine for me. I didn't test the Windows case, but of course, that has to work as we're using the correct shebang for Windows to begin with.

Related

Make VS Code terminal match debug environment on a Mac

I'm teaching a beginners python class, the environment is Anaconda, VS Code and git (plus a few extras from a requirements.txt).
For the windows students this runs perfectly, however the mac students have an existing python (2.7) to contend with.
The windows students (i.e. they have a windows computer), their environment when they debug matches their console environment. However the mac students seem to be locked to their 2.7 environment.
I've tried aliasing, as suggested here and here
alias python2='python'
alias python='python3'
alias pip2='pip'
alias pip='pip3'
I've modified the .bash_profile file
echo 'export PATH="/Users/$USER/anaconda3/bin:$PATH"' >>.bash_profile
Both of these seem to work perfectly to modify their Terminal environments, when launched externally to VS Code. Neither seem to do anything to the environment launched from [cmd]+[`].
I've also tried conda activate base in the terminal, which seems to have no effect on a python --version or a which python
They can run things using python 3, but that means that they need to remember that they are different to the other 2/3 of the students. It's othering for them, and more work for me!
The students are doing fine, launching things from their external terminal, but it would streamline things greatly if the environments could be as consistent as possible across the OSs.
Whilst they are complete beginners, they can run a shell script. They currently have one that installs pip requirements and vs code extensions.
Is there a configuration that will keep the terminal in line with the debug env?
In my opinion the best practice is to create Python virtual environments (personally I love using conda environments, especially on Mac where you stuck with unremovable old Python version). Then VSCode will automatically (after installing very powerful Python extension) find all your virtual environments. This way you will teach your students a good practice of handling Python zoo a.k.a. package incompatibilities. Terminal environments settings will be consistent with VSCode, without being dependent on unneeded any more aliases. Obviously, virtual environments are OS independent, so you will be more consistent and remove unnecessary confusion between different students.
The additional bonus of the virtenvs is that you can create one exactly according to your requirements.txt and switch from one to another with a single click (in terminal it takes two commands: deactivate -> activate).
You can read more about how to handle Python virtual environments on VSCode site
Given the aliases are run just once and are not persistent in .bash_profile, python targets the default interpreter rather than the expected conda python3 interpreter.
Try to symlink conda's python3 executable to capture the python namespace
ln -sf /Users/$USER/anaconda3/bin/python3 /Users/$USER/anaconda3/bin/python
This will create or update the symlink. Use the same approach for pip and pip3.
Python in vscode let's you select which interpreter will be used to run the scripts.
It is in settings under "python.pythonPath", just set it to point to the interpreter of choice.
It can be set on a project basis as well (which is how you ensure that a project that has a virtual environment will execute using that interpreter and packages), you just select Workspace in the settings pane and add the desired python interpreter there.

Emacs and conda workaround

I'm using emacs and anaconda.
I have this in my init.el:
(setenv "WORKON_HOME" "/home/user/anaconda3/envs/")
And conda on my path:
# added by Anaconda3 installer
export PATH="/home/user/anaconda3/bin:$PATH"
but emacs can't find my conda environments, which I understand it is supposed to be able to do..
So, when I run C-c C-p to start a new session, and C-c C-c, it fails to import my packages which are installed in a conda environment, with ModuleNotFoundError.
Since I have added this to my path and it still doesn't work, I am trying to work around this, and still be able to run my conda applications from emacs.
I can open a shell in emacs with M-x shell, then source activate myenv, and run python.
I now want C-c C-c to copy into /this/ shell. How do I mark this shell buffer as a python process to send my file.py's text to on C-c C-c, rather than just a shell shell?
Update1
I've also looked at the following references:
https://emacs.stackexchange.com/questions/20092/using-conda-environments-in-emacs
How does conda-env list / conda info --envs find environments?
But neither package works for me. I still get, when I try:
conda-env-list
*Conda envs*
Produces a blank buffer.
And this for pyvenv-workon:
pyvenv-workon
Work on: (empty)
These environments very much exist, and it makes it impossible to use emacs as a python IDE if I can't run my code.
What I found works for me is to use the conda package from ELPA and set two of its configuration variables to point to my Conda directory. The following snippet does the trick in my .emacs:
(use-package conda
:ensure t
:init
(setq conda-anaconda-home (expand-file-name "~/miniconda3"))
(setq conda-env-home-directory (expand-file-name "~/miniconda3")))
conda-anaconda-home is the equivalent to the ANACONDA_HOME environment variable (i.e. contains all files of your Anaconda installation)
conda-env-home-directory - is the directory where your virtual environments get stored (within the envs subdirectory)
With this configuration I'm able to run M-x conda-env-activate and have access to all previously created envs.
Programs inherit the environment variables from the shell that spawned them. The way conda and virtualenv work is by overriding the shell's PATH variable. They do this so that the OS finds the new version of the app (conda's or virtualenv's) instead of the default one installed with the OS (Macs come with an ancient version of python).
So, what is happening here? If you start Emacs by double clicking on the OS icon it will inherit the default shell environment variables. So when you try to call a library that you installed with conda (or equivalently with virtualenv and pip), because you are using the default OS path, the OS is finding the default version of python (and crucially the default version's libraries). The default version of python is going to respond "I have no idea what library that is."
How to fix? One reliable way is to not start Emacs by double clicking on the OS Icon. Here is what I do most days:
1) start a console/terminal
2) switch to the conda environment `activate py37`
(or with virtualenv: `source .py37dev/bin/activate`)
3) start Emacs from that same shell that has the modified environment variables.
On a Mac its: `/Applications/Emacs.app/Contents/MacOS/Emacs`
(I use a installed version of Emacs on the Mac because the one that
comes with Mac is ancient).
On Linux and Windows the path to EMacs will be different but the idea is the same.
4) start a shell inside Emacs and you should see the shell looks the way it does
in your conda shell (or virtualenv shell)
here it what it looks like for me:
see how the version of python is not the default OS python? Its the one from the virtualenv + pip environment (conda works the exact same way, just the start envirmonment is a different command)
I tested the solutions given in the answers of Wojciech Gac, of Mittenchops and James Anderson.
While solution of James Anderson's solution is by far the easiest, it comes with a few problems:
First, you have to reactivate the environment in each shell process you spawn in emacs. There is also the possibility that emacs has a different pythonpath, therefor reluctantly using system python and not venv python.
The solution with conda.el is somehow weird. In Melpa it is listed as obsolete and with instructions of https://github.com/necaris/conda.el it won't recognize the environments on my certain machine.
On the same machine the solution with pyenv as mentioned in https://emacs.stackexchange.com/a/20093/28567 is working like a charm.
Therefor you only need to install with M-x package-install search for pyenv and then insert following two lines into .emacs:
(setenv "WORKON_HOME" "~/anaconda3/envs") ; /anaconda3 || /miniconda || wathever path your conda installation is located at
(pyvenv-mode 1)
This is my minimal solution to this problem:
create a batch file like this
conda activate <yourEnv>
python -i
set (local) python-shell-interpreter pointing to the batch-file
run-python as always (C-c C-p ...)
I know this is not exactly an answer to your question. But If you JUST want to run your code, open the directory in the terminal where your files are located (e.g. cd /Downloads/Chapter01/yourfile.py) . Then, activate the environment (conda activate *your env*) and pass this command (python yourfile.py). Your code will be executed within that environment by python.
I edit remote files with emacs and run code like this in another terminal window. You may wanna open the two terminal windows side by side while debugging your code.

How to customise a virtual environment in Python correctly?

I have to develop software with the use of several programs together, like Python 3.6 (with specific packages), WKHtmlToPdf and an embedded browser (based on CEF). I should be able to share all this together in one directory, so with a virutal environment of Python 3.6...
My question to you all is: how can I make the paths of a Python virtual env relative.
A second question I have is: is it possible to just activate the virtual env without changing cmd prompts and things? I tried to write a batch file which 1) starts the environment, 2) executes a Py script and 3) runs the embedded browser. That batch file failed after it started the virtual environment...
I should be able to share all this together in one directory, so with a virtual environment
Virtual environments are not portable (they must reside in the same directory on a computer where exist global Python), hence you cannot share a virtual environment.
My question to you all is: how can I make the paths of a Python virtual env relative.
No, and you certainly don't need to do it.
A second question I have is: is it possible to just activate the virtual env without changing cmd prompts
Yes, it's regulated in bin/activate script which you can edit to your taste.
and things?
What "things"? Activating virtual environment means changing PATH, PYTHONPATH and so on, you certainly cannot use virtual environment without changing these and other things.
That batch file failed
If you want us to help you should show us the essential parts of the batch and in what way it failed.
May be you need a different solution like a Docker image. Docker can be installed on Windows though it must be installed on the target computers.
There are also simpler solutions: py2exe, PyInstaller, cx_Freeze. They "compile" python scripts to .exe and accompany that .exe with Python interpreter (in a .dll) and library (in a .zip file). But if your program needs more DLLs you have to copy them to the target computer.
You can also take a look at RVirtualEnv. It allows to create relocatable virtual environments. I don't know if such envs can be copied to a different host, though.

Using linux console in pycharm

I'm new to pycharm, virtualenv, linux and git.
I've recently begun a journey of using djangoto make webapps. Before I used sublime to make scripts however now a more complex project management system such as pycarm was needed. I actually wanted to get a linux VM and go down that road but was advised that windows python IDE such as pycharm would be suitable
I recently learnt the importance of dependencies and how to use virtualenv. However in this tutorial, under the 'How do I use my shiny new virtual environment?' it starts using commands such as:
ls env
and
which python
Neither of which my pycharm console would understand.
I could use a console emulator such cmder to use the commands but then I would remove the convience of using the IDE's integrated one.
Should I upgrade to a linux VM ? Or can I install a package that allows me to use such commands in PyCharm.
As a bonus question, what are the commands in that tutorial ? are they linux commands? when ever i see $ .... is that the linux console ?
You can accomplish this using Vagrant: https://www.vagrantup.com/
You can use Vagrant and VirtualBox to setup a Linux VM (distro of your choice) and then install all of your Python dependencies in the VM. Once you have that setup, you can tell PyCharm to use the Python interpreter in your VM by following these steps:
Open the project settings dialog box in PyCharm.
Expand Project: (your project name) on the left side.
Click on Project Interpreter.
Click on the cog icon on the upper right side of the window and select Add Remote.
Click on the Vagrant radio button.
In the Vagrant Instance Folder box, select the directory your Vagrantfile is located in.
In the Vagrant Host URL box, make sure ssh://vagrant#127.0.0.1:2222 is specified.
Click OK.
Since Vagrant is compatible with Windows this solution should work for you. I have done it successfully using macOS and it works great. Good luck!
You might find this tutorial useful: https://developer.rackspace.com/blog/a-tutorial-on-application-development-using-vagrant-with-the-pycharm-ide/
I got this to work on Windows 10 with Anaconda Prompt. This terminal which comes with Anaconda, creates a "base" environment with a linux-like virtual machine and your Windows file system (C:\\) mounted to /c, and has bash installed with common Unix commands like cd, ls, chmod, echo, cat, ... Running programs from bash with access to environment variables is much nicer than Windows Powershell etc.
Now to get your Terminal in Pycharm to use Anaconda Prompt instead of cmd.exe, I followed this answer. After installing Anaconda and/or Anaconda Prompt, right-click -> Open File Location -> right-click the shortcut -> Properties -> copy file path. Then use your file path instead.
Conda is great for package environment management. Learn more about it here. For Django + Conda specifically, read here. You can also use pip to install from Python package indexes, github repos, and requirements.txt files instead. Unless you know how Anaconda Prompt works, I don't recommend creating your own environments from scratch. What worked for me was:
(base) C:\Users\wassadamo> conda create -n mynewenvironment --copy base
...
(base) C:\Users\wassadamo> conda activate mynewenvironment
(mynewenvironment) C:\Users\wassadamo> ls
folderA folderB file.txt
Works!
Whenever I try running conda deactivate to leave the base environment, my bash commands would stop working. So clone base as above.
Another tip: if you want to run shell scripts from Terminal within PyCharm with Anaconda Prompt this way, then execute them (e.g. "run.sh") on command line with
bash run.sh
I tried putting this on the first line of my run.sh
#!/usr/bin/bash
And running it with
./run.sh
But this had the effect of running it in an external Anaconda Prompt instance (add sleep, or some user input command to force it to wait and see for yourself). Explicitly running my .sh files with bash had the desired effect of running them in the same shell as I started them in PyCharm Terminal configured with Anaconda Prompt.

Running python from the mac terminal

I have installed the new python release and would like to run .py files from the terminal.
How is this done from the terminal? I dont want to include the path in each command to run a .py file.
If you want to override the python command, you can set your PATH variable correctly, e.g. in your ~/.bash_profile:
export PATH=/path/to/python/:$PATH
That said, for managing different versions of components that are also provided by Mac OS X, I suggest to use a package manager such as Homebrew.
if you add a shebang at the start of the python file then you can run a python file by just its name from terminal
add #!/usr/bin/python
for mac(others add your respective path for python)
at the top of your python program and from your terminal you can run it just by filename(if it has executable permissions).
Have a look at the Python package under Applications. There is a shell script there called Update Shell Profile.command
Run this and it should set your path up properly.
Unless you mark you script as executable with chmod +x, you'll need to run python over it first. e.g. `python myscript.py'
I installed all of my python through macports, which has pros and cons. One of the benefits is that you don't have to worry about stuff like this, it just works. You can install python 2.6 and python 2.7 (and others), and then use the python_select utility to set up which python is run when you call "python blah.py"
Since you have installed a working python, the easiest way to run python files from the terminal is to cd your terminal to the directory where the file is located and then just type python my_code.py in the terminal.

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