# Setup python, pip, virtualenv and virtualwrapper, with zsh on a new machine

Strongly inspired by <https://gist.github.com/heymonkeyriot/9a2f429caff5c091d5429666fa080403>.

## Installing Python & Pip

On Ubuntu :

```bash
sudo apt install python3 python3-pip
```

or on Fedora < 31 :

```bash
sudo dnf install python3 python3-pip
```

That'll install both Python and PIP.

(Side note that you should install multiple versions of Python via Pyenv rather than Brew/apt/dnf to avoid any bad Python conflicts)

## Installing Virtualenv & Virtualenvwrapper

Install all your python env into local.

```bash
pip3 install --user virtualenv virtualenvwrapper
```

You'll need to tell ZSH where virtualenvs scripts are located

In ~/.zshrc add the bin folder to the path **before** the plugins part :

```bash
# Add the bin folder to $PATH before the plugins load
PATH=$HOME/.local/bin:$PATH
```

Also, add the `virtualenvwrapper` to the *plugin* array :

```bash
plugins=(
        git
        ...
        virtualenvwrapper
    )
```

Then you can load your shell with this new config :

```bash
source .zshrc
```

You might get into errors :

- Virtualenvwrapper plugin doesn't find the path of `virtualenvwrapper.sh` :

    ```bash
    [oh-my-zsh] virtualenvwrapper plugin: Cannot find virtualenvwrapper.sh.
    Please install with `pip install virtualenvwrapper`
    ```

    To fix it, you can put the correct path in the *virtualenvwrapper* plugin. **Note: I don't find these very elegant, you'v probably forgot to update your PATH before.**
    For example, change all the lines of `~/.oh-my-zsh/plugins/virtualenvwrapper/virtualenvwrapper.plugin.zsh` from `/usr/local/` to `$HOME/.local` (if you've installed locally the modules).

    You can do it with one commande line with

    ```bash
    sed -i "s/\/usr\/local/\$HOME\/.local/g" ~/.oh-my-zsh/plugins/virtualenvwrapper/virtualenvwrapper.plugin.zsh
    ```

- The `virtualenvwrapper.sh` script throws an error like :

    ```bash
    virtualenvwrapper_run_hook:12: permission denied:-
    virtualenvwrapper.sh: There was a problem running the initialization hooks.
    ```

    It's probably your system use `python3` command and not `python`. Adding `alias python=python3` doesn't seem to work.

    You need to add in `.zshrc`, before the plugins line :

    ```bash
    export VIRTUALENVWRAPPER_PYTHON=$(which python3)
    ```
    
- `ERROR: Environment '/home/john_doe/.virtualenvs/test-env' does not contain an activate script.` on a Raspberry Pi
    
    First check your version of virtualenvwrapper with `pip freeze | grep virtualenv`, it should be `4.x.x` and not `5.0.0`. If necessary downgrade your version with `pip uninstall virtualenvwrapper` and `pip install --user virtualenvwrapper=="4.8.4"` (check the last version at [PyPi](https://pypi.org/project/virtualenvwrapper/#history)).
    
    Then you can have the same issue is the as above, so just add `export VIRTUALENVWRAPPER_PYTHON=$(which python3)` to your `.zshrc` (or `.bashrc`) **before** loading the plugin.

## Use virtualenvwrapper

When the `source` doesn't throw any errors, you can test if *virtualenvwrapper* works.

```bash
workon
mkvirtualenv test
```

Here you should see

```bash
New python executable in /home/john_doe/.virtualenvs/test/bin/python2.7
Also creating executable in /home/john_doe/.virtualenvs/test/bin/python
Installing setuptools, pip, wheel...done.
virtualenvwrapper.user_scripts creating /home/john_doe/.virtualenvs/test/bin/predeactivate
virtualenvwrapper.user_scripts creating /home/john_doe/.virtualenvs/test/bin/postdeactivate
virtualenvwrapper.user_scripts creating /home/john_doe/.virtualenvs/test/bin/preactivate
virtualenvwrapper.user_scripts creating /home/john_doe/.virtualenvs/test/bin/postactivate
virtualenvwrapper.user_scripts creating /home/john_doe/.virtualenvs/test/bin/get_env_details
```

You should see a `(test)` somewhere in you shell, but it might depend of the theme. (By default the ZSH virtualenv plugin hides the virtualenv name with `export VIRTUAL_ENV_DISABLE_PROMPT=1`. That's why I didn't add it to plugins, it doesn't seem very useful but migh be linked with the theme I use.)

If you obtain the error `ERROR: virtualenvwrapper could not find virtualenv in your path`, check if you've add the `bin` folder to *$PATH* (see above).

Do whatever you want in your *venv*. Then to quit and delete.

```bash
deactivate
rmvirtualenv test
```

If the zsh plugin works correctly, you can link a venv to a **git** folder (auto `workon` and `deactivate` when you navigate in and out the folder. First create the folder `test` (usually a `git clone`). Then `mkvirtualenv test`. It should work, hopefully.