ferret 0.4.0

a snake that runs. execute python files without packaging or installation

ferret
======

python, but with running.

``ferret`` provides a new shebang line for your python script that will install dependencies into a fresh ``venv`` - saving you the hassle of packaging and distribution. ``ferret`` lets you focus on writing just the code you need without sacrificing libraries.

usage
-----

* Install ``ferret`` on the target environment with either:
.. code-block::

pipsi install ferret
# or
pip install --user ferret

* Replace your shebang line with this:
.. code-block::
#! /usr/bin/env ferret

* Declare your dependencies in your module's docstring:
.. code-block:: python
"""
A helpful description about your module

ferret:
- requests == 2.18.4
"""


When you run a script with ``ferret``, it parses the file for dependency declarations, and prepares a ``venv`` to match. The environments are kept under ``~/.local/ferret/venvs`` (you can safely delete the entire contents of that folder).

example
-------

Once you've installed ``ferret``, take it for a spin:

.. code-block:: python

cat > just_a_script.py << EOF
#! /usr/bin/env ferret
"""
Gets my IP from icanhazip.com

ferret:
- requests == 2.18.4

"""

import requests

response = requests.get('http://icanhazip.com')
response.raise_for_status()
print(response.text())
EOF
chmod +x just_a_script.py
./just_a_script.py


The first time you run the script, ``ferret`` will set up a ``venv`` and install ``requests`` in it. Subsequent runs will re-use that environment.