How to run virtual environment from shell script? - linux

I am trying to setup my project environment from a shell script on ubuntu so that I can skip basic setup every time.
I use my virtual environmet cv using the command workon cv.
But I am having trouble doing so using a shell script. I tried the the script
#!/bin/bash
workon cv
But I get the error
workon: command not found
I try to list all the venv I have
pran#pran-HP-65-Notebook-PC:~$ lsvirtualenv
cv
==
virtual-py2
===========
Also, I thought of locating it
(cv) pran#pran-HP-65-Notebook-PC:~/.virtualenvs$ l
cv/ postdeactivate preactivate* prermvirtualenv*
get_env_details* postmkproject* predeactivate virtual-py2/
initialize postmkvirtualenv premkproject*
postactivate postrmvirtualenv* premkvirtualenv*
How can I do it?

You cannot execute workon command outside of Python virtual environment.
If you are interested, check out this article that will walk you through all of the steps required to set up your virutal env.
If it is not what you need then please clarify your requirements for a project environment.

I found the solution:
My venv was located in .virtualenvs. So, I put the command in the bash file start.sh (meant to be executed before working on my project).
#start.sh
source ~/.virtualenvs/cv/bin/activate
And run it using
$ source start.sh
It works perfectly 👍

Related

pipenv shell working but an error is displayed

If I run the command:
pipenv shell
in my Mac shell, everything works fine and a new virtual environment is created and activated:
.../django_celery_rabbit_flower$ pipenv shell
Launching subshell in virtual environment...
bash: parse_git_branch: command not found
.../django_celery_rabbit_flower$ . /.../django_celery_rabbit_flower-rEt8HW1V/bin/activate
bash: parse_git_branch: command not found
(django_celery_rabbit_flower) .../django_celery_rabbit_flower$
but a bash error is displayed:
bash: parse_git_branch: command not found
I do not understand where it come from. Any idea?
UPDATE
Jen answer trigger a little thought. I have checked my ./bash_profile and I can see the line:
export PS1="\[\033[36m\]\u\[\033[m\]#\[\033[32m\]\h:\[\033[33;1m\]\w\[\033[m\]\$(parse_git_branch)\$ "
This shows the git branch on the bash prompt. So I believe vscode uses this settings. The folder I am working on is not a git folder. Can I write an if statement to avoid the error being displayed when running the python virtual environment?
Instead make sure that the command does actually exists before running it.
PS1="...."'$(if hash parse_git_branch >/dev/null 2>&1; then parse_git_branch; fi)'"..."

Activating virtual environment environment

please for a while now i've been trying to activate virtual environment for my windows 7 machine; I've run commands like env\Scripts\activate where env is the installed virtual environment folder in the project, but each time i run the command, it gives me an error like: activate is not recognized as an internal or external command, operable program or batch file. Please what could be the problem, what should i do?
Do you have activate.bat inside Scripts folder? If yes, run that. If not, delete everything and run python -m venv env again and let me know what happens. Please note that you may change env to whatever you want.
Here it is (just google it, there are a lot of post explaining that):
https://programwithus.com/learn-to-code/Pip-and-virtualenv-on-Windows/

How to switch virtualenv in shell script?

For my personal project, I'm trying to analyze the technical debt of various python libraries. For this, I made python script which downloads the library, checks out to each merged commit and runs the analysis. One part of the analysis is to get the test coverage.
The easiest way I found to get it is to run
coverage run --source={library}/ setup.py test
However, I want to have this automated so I'm trying to run this command in a shell script from the python script mentioned above.
The script shall change the dir to the library, switch to virtualenv (automatically created in the previous steps of the analysis) and run the coverage. However, it fails on Requirement error which indicates that it does not actually switch the virtualenv and stays in the virtualenv of the analysis project.
The shell script looks like this:
#!/usr/bin/env bash
# Args
# $1 proj_path
# $2 proj_name
# $3 venv_name
cd $1
source `which virtualenvwrapper.sh`
workon $3
coverage run --source=$2/ setup.py test
coverage report
And it's called from the python script like this:
subprocess.call(["analyzer/run_coverage.sh", self.repo_path, self.repo_name, self.venv_name])
Could you please help me how to switch the venv in the shell script? Thanks!
Script 'activate' activates virtual env, and 'deactivate' deactivates virtual env:
https://virtualenv.pypa.io/en/stable/userguide/
Example of the loop over two virtual environments stored in bash array:
venvs=(~/venvs/py3.6.4 ~/venvs/py3.7.0)
$ for i in "${venvs[#]}"
do
source "$i"/bin/activate
which python
python --version
deactivate
done
/home/gbajson/venvs/py3.6.4/bin/python
Python 3.6.4
/home/gbajson/venvs/py3.7.0/bin/python
Python 3.7.0

Activate virtualenv using alias

I can activate my python virtual environment from it's folder by entering . bin/activate. I'd like to instead type a single word alias, such as shazam, from the home folder (or anywhere else) that activates the environment, changes to my master project folder, and lists my projects.
I tried creating an alias in .bashrc that pointed to an .sh file containing:
cd ~/path-to-virtual-environment
. bin/activate
cd ~/path-to-master-project-folder
ls -a
I was getting a permission denied error, so I ran chmod u+x <script file>. The script now runs, but the VE does not activate and while the project folders are listed, the shell is not in the master project folder. I would appreciate some guidance. Thanks.
Recreate all your environments in ~/.virtualenvs and install virtualenvwrapper. The command to activate an env is workon shazam. Command line completion is supported.
Now about your problem: you've tried to activate an environment in a shell script. That doesn't work because shell scripts run with another shell and env activation change their environments, not the current. I.e., the environment briefly activated but then at the end of the script the new shell exits and the environment deactivated.
There are two ways to overcome this.
Use aliases or shell functions instead of scripts — they are the only way to change the current shell's environment.
Run interactive shell at the end of your script (exec $SHELL). It inherits activated environment and gives you a command prompt. To deactivate simply exit the shell (exit or [Ctrl]+[D].).

Run a python script in virtual environment from windows task scheduler

I'm trying to set up a recurring Python task through windows task scheduler.
I have had success when I input the path to 'python.exe' and provide the script's path as a parameter to windows task scheduler (see screenshot below)
However, I want to be able to choose a particular virtual environment in which to run the script. I don't have much knowledge of venv, and I typically use it by opening cmd and running Scripts\activate.bat in the desired virtual environment directory.
How can I accomplish 'run task x in venvxxx every 24 hours' using windows task scheduler?
Create batch file with these commands:
c:\__full_path_to_virtualenv__\Scripts\activate.bat && python __full_path_to_python_script__.py
&& means run command2 if command1 completed successfully.
Then set that batch file as script to run. You don't need to set any additional arguments in task scheduler (or you can set them in batch file anyway) and can set Start in if script has to read/write from specific directory and uses relative paths.
Though the answer by mx0 above seems to work, I have set up Task Scheduler to run a flask web app on bootup. In this case, manual starting works fine, but manual ending does not. Ending the task kills the cmd.exe task that sets up the virtual environment, but the python.exe continues to run.
The solution that I found worked was from this reddit post which skips the virtual environment activation to call the python executable directly:
path\to\venv\Scripts\python.exe path\to\script.py
I'm not sure how robust this will be, but at least this way ending the task will end the python.exe
This is more verbose but very easy to understand, and - I found the most important - much easier than using Windows Task Scheduler settings when you have lots of scripts. To create another you just copy the .bat file and change one line.
Save this as a .bat file and point to it under Actions > Start a Program > Program/Script:, with no arguments or "Start in" necessary.
set original_dir=%CD%
set venv_root_dir="C:\Python-Venvs\env-name"
cd %venv_root_dir%
call %venv_root_dir%\Scripts\activate.bat
python your_script.py <arg1> <arg2>
call %venv_root_dir%\Scripts\deactivate.bat
cd %original_dir%
exit /B 1
For an installed command-line program, you can replace python your_script.py <arg1> <arg2> ... with <program name> <arg1> <arg2> ....
In addition it's simple to add another script on the following line, rather than attempting to parse sequential scripts into a one-liner for Task Scheduler.
I tried with mx0's answer and it works fine as long as your script does not take too long to finish.
I use a different approach in the task scheduler instead using batch files:
In "Program/script" textbox you set the path to Python executable (in my case is inside the virtualenv folder).
"Add arguments" => Just the name of your Python script (name.ppy).
"Start in" => The full path of your Python script (without the name.py).
This way the script runs and wait until the end.
My solution is almost identical to mx0, but I've added an extra step to ensure environment parameters each time. Edit the path/to/app for the app_path variable.
It may be a little redundant to check the environment setup every time, but I like ensuring my environment is set.
Simply schedule the execute_app.bat file or run in the cmd prompt. Deactivate command is not needed unless running from an Anaconda prompt. If you use a full path for path/to/app this file can be executed from any directory. I also have a Linux solution using execute_app.sh file below from a terminal.
This answer has been edited to simplify, and to use variables to make this easier to adapt to new projects.
App structure:
app/bin/app.py
app/bin/execute_app.bat
app/env/requirements.txt
# execute_app.bat file
# windows solution
SETLOCAL
set app_path=path/to/app
set env_path=%app_path%/env
set activ=%env_path%/Scripts/activate.bat
set req=%env_path%/requirements.txt
set app=%app_path%/bin/app.py
py -m venv %env_path% && %activ% && python -m pip install --upgrade pip && pip install -r %req% && python %app%
ENDLOCAL
#!/bin/bash
# execute_app.sh file
# Linux solution
app_path='path/to/app'
env_path=$app_path'/env'
activ=$env_path'/bin/activate'
req=$env_path'/requirements.txt'
app=$app_path'/bin/app.py'
python3 -m venv $env_path &&
. $activ &&
python3 -m pip install --upgrade pip &&
pip install -r $req &&
python $app &&
deactivate
The selected answer for this question is not correct. If you review the comments, you'll see the problem.
My answer builds off of #Nick P's answer (the #2 answer currently). His batch file will work, but you'll want to change the exit code from 1 to 0 if you want Windows Task Scheduler to report the task completed successfully. Also, simply calling the .bat file on the "Program/Script" line will not work. Instead, you need to put the name of your shell as the "Program/Script" to run (for instance, cmd), then put "/c name-of-batch-file.bat" goes in the "Add arguments (optional):" field. And finally, put the path to the batch file (minus the file name) in the "Start in (optional):" field.
It should look something like this:
REM Windows batch script to run 1+ Python program/scripts, sequentially, within
REM their virtual environment. This can be called from Windows Task Scheduler.
set original_dir=%CD%
set venv_root_dir="C:\Users\myUsername\myProjects\nameOfProject"
cd %venv_root_dir%
call %venv_root_dir%\Scripts\activate.bat
python nameOfPythonProgram.py
call %venv_root_dir%\Scripts\deactivate.bat
cd %original_dir%
exit /B 1
Copied this from nmpowell on github and it works fine. Run from task scheduler
Solution
Patching the path is all necessary.
The quick way would be a bat script that source environment activation script at the beginning
#call PATH_TO_MY_VENV/bin/activate.bat
python app.py
Proceeding Problem
Later you will realize that the python job starts fine, but won't stop when Windows Scheduler stop it.
When taskengine.exe decides to stop the job, the intermediate cmd.exe (bat script) process is killed and the Python.exe will be left straw. since the cmd.exe(bat script) won't signal python.exe to stop on exit.
Final Solution
Let Windows Task Scheduler or taskengine.exe launch python.exe directly without a middle-man script.
Previous answers launch python.exe directly with py script, this works for simple modules, but not for some binary module in conda environment.
For binary modules in conda to work, you can create a utility module named e.g. patch_conda_path to patch PATH variable in os.environ based on sys.base_exec_prefix. Copy the patching work that activate.bat does, just in python.
below example has been tested for conda virtual environment:
import is, sys
conda_base = sys.base_exec_prefix
subps = [";", "library\\mingw-w64\\bin;", "library\\usr\\bin;", "library\\bin;", "scripts;", "bin;", "condabin;"]
conda_paths = ""
for p in subps :
_p = os.path.join(conda_base, p)
if _p in os.environ["PATH"]:
continue
else:
conda_paths += _p
os.environ["PATH'"] = conda_paths + os.environ["PATH"]
Import this module at the beginning of your main script.
import patch_conda_path
... original main script ...
In task scheduler set
program to ... conda environment path...\python.exe,
arguments to your py script file name and
start in to your py script folder.

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