# Python

## Package Caching Proxy

Instead of accessing pypi.org directly PSI provides a caching proxy for pypi packages. There are several advantages in using this instead of directly accessing pypi.org:

1. Speed - the caching proxy might/will improve the dependency resolution and download speed for installing packages
2. Once downloaded/installed packages will still be available even if they are not accessible on the internet again.
3. Accessibility - pypi.psi.ch is accessible from all PSI networks (including the onces without internet access)

###  Usage
The url to use the CachingProxy is: https://pypi.psi.ch/simple:

You can manually specify the url while using the `pip` command as follows:
pip install --index-url=https://pypi.psi.ch/simple pandas


To fix the default url for your user to the proxy you can create the following config file within your users home directory:

```bash
% cat ~/.config/pip/pip.conf 
[global]
timeout = 60
index-url = https://pypi.psi.ch/simple
```

To change the default for the whole system edit: `/etc/pip.conf`
(also see: https://pip.pypa.io/en/stable/topics/configuration/#location) 

To check whether your pip client is using this address you can simply issue a:
```
pip install -h
```

Check whats written in the descripiton of the option --index-url:

```
% pip install -h | grep -A5 index-url 
  -i, --index-url <url>       Base URL of the Python Package Index (default
                              https://pypi.psi.ch/simple). This should point
                              to a repository compliant with PEP 503 (the
                              simple repository API) or a local directory laid
                              out in the same format.
...
```

or do a `pip config list`
```
% pip config list
global.index-url='https://pypi.psi.ch/simple'
global.timeout='60'

```