python/README.md

In TWJolly/CivilServiceR: What the Package Does (One Line, Title Case)

Python

Using version 3.8.3 (the version I happened to have locally)

Local development

Dependencies

While developing locally, I'm using a virtual environment to help manage the dependencies without mixing them up with any other local Python projects. See https://docs.python.org/3/tutorial/venv.html

You should 'activate' the virtual environment before installing dependencies, so that they are installed in the virtual environment.

# be in the python folder
cd python

# create a virtual environment in the directory .venv
python3 -m venv .venv

# activate it
source .venv/bin/activate

With an activated environment you can then run

• pip install to install any new dependencies in the activated environment
• python -m pip freeze > requirements.txt to create a record of the dependencies and their versions
• And crucially, you can tell pip to read the requirements.txt to install all the correct dependencies, using python -m pip install -r requirements.txt. This makes life easier because you verify that you're working in a similar/identical environment as your collaborators/the deployment, reducing the likelihood of unreproducable bugs; and it means we can have a single source of truth when we want to programmatically install all the correct versions of things.

Environment variables

I am using the dotenv library to manage environment variables locally and avoid them conflicting with environment variables in other projects. I don't know how well this translates to the deployment environment.

.env.example shows which environment variables you'll need. You can copy this file into a new file .env and fill in the values.

How to access an environment variable in python:

from dotenv import load_dotenv
load_dotenv()
import os
MY_SECRET_KEY = os.getenv("NAME_OF_KEY")

For AWS

To access AWS programmatically, you'll be directed by their documentation to (either automatically or manually) update your ~/.aws/credentials. But the default way of doing this will cause conflicts with any other AWS projects you are doing. Although you can store more than one profile in ~/.aws/credentials, as here, it's going to be simplest to store these keys as regular environment variables like above.

TWJolly/CivilServiceR documentation built on May 16, 2022, 5:45 a.m.