Update wsgi, add venv

web/wsgi.markdown

@@ -2,16 +2,47 @@
 
 Please first read our documentation about [[/web/webshares]].
 
-We allow to host Python 3 web applications using [WSGI](https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface), which is enabled on demand only (please [[contact us|services/contact]]).
+We allow to host Python 3 web applications using [WSGI](https://en.wikipedia.org/wiki/Web_Server_Gateway_Interface),
+which is enabled on demand only (please [[contact us|services/contact]]).
 
-- The WSGI app lives at: `/home/wwwshare/public`
-- The WSGI entry point is usually at: `/home/wwwshare/public/wwwshare.wsgi`
+## Basic usage
 
-If you make changes to the source code, you have to tell the webserver to restart the WSGI app by modifying the file time stamp on the WSGI entry point:
+- WSGI app directory: `/home/wwwshare/public`
+- WSGI entry point: `/home/wwwshare/public/wwwshare.wsgi`
+
+All new WSGI webshares will come with a dummy app in `wwwshare.wsgi`.
+Edit this file to load your application.
+
+If you make changes to the source code, you have to tell the webserver to
+restart the WSGI app by modifying the file time stamp on the WSGI entry point:
 
 ```bash
 touch /home/wwwshare/public/wwwshare.wsgi
 ```
 
-Our WSGI uses a [virtual environment](https://compenv.phys.ethz.ch/python/ecosystem_1/30_virtual_environments/) at `.venv/`, which contains any custom python modules.
-Some python modules may be installed system wide if they are used on multiple websites (like for example Django).
+## Static content
+
+If your app hosts static content, please inform us about the relative path(s)
+to the location(s) in `/home/wwwshare/public`, that contains static content.
+
+## Virtual environment
+
+Our WSGI uses a [virtual environment](https://compenv.phys.ethz.ch/python/ecosystem_1/30_virtual_environments/) (venv),
+which contains any custom python modules and is activated by our webserver configuration.
+
+- Location: `/home/wwwshare/private/venv`
+- Requirements: `/home/wwwshare/private/requirements.txt`
+- Freeze: `/home/wwwshare/private/freeze.txt`
+
+If your app needs custom python modules, please specify them in the
+[requirements file](https://pip.pypa.io/en/stable/reference/requirements-file-format/).
+We will have to generate a new venv should there be any changes,
+so please [[contact us|services/contact]] in that case.
+
+In the future we might provide a way for you to re-generate the venv yourself.
+But this should not be needed often, since development should happen on your local machine
+and your app should only be deployed to our server once it is stable.
+
+The freeze file will be automatically generated and contains all installed modules and versions
+in the venv. It is needed to reproducibly re-generate the exact current state of the venv later,
+please do not modify this file.