CO2 tracker app

Purpose

This app is a script intended to be run daily to gather the previous day French energetic mix CO2 emission data.

Design decisions

Architecture

The CO2 tracker script is designed with a modular and extensible architecture to facilitate future enhancements and adaptability. The main components include a records fetcher, responsible for obtaining CO2 data from external APIs, and a records writer, managing the output of CO2 records either to files or the console. The use of dependency injection allows for dynamic configuration of these components, making it easy to swap out implementations or extend functionality without modifying the core logic. The script employs a command-line interface, making it easy to configure the source of data and output preferences.

Usage of UTC times

The script uses UTC as the standard timezone. This choice is aimed at streamlining operations and minimizing potential issues related to time zone conversions. The responsibility for displaying localized datetime information should be delegated to the frontend.

Requirements

• click: a CLI builder tool
• httpx: a performant alternative to requests supporting both synchronous and asynchronous requests
• pydantic: a fast and extensible data validation library

Extending the script functionalities

Adding a fetcher

It is easy to add a new fetcher (e.g. fetching data from a different API):

• write a fetcher class implementing to the RecordsFetcherInterface
• add it as a new strategy in the records_fetcher_builder function in main.py

Adding a writer

It is easy to add a new writer (e.g. writing the records to a database):

• write a fetcher class implementing to the RecordsWriterInterface
• add it as a new strategy in the records_writer_builder function in main.py

How to run

Running manually

Use the --help command to show the different parameters

❯ python3.11 -m venv venv && source venv/bin/activate
❯ python main.py --help
Usage: main.py [OPTIONS]

Options:
  --fetcher [ecoco2mix]    API from which to fetch C02 data
  --writer [file|console]  Writer to which records are outputed
  --folder TEXT            Folder to which files are stored (if writer=file)
  --prefix TEXT            Filename prefix (if writer=file)
  --help                   Show this message and exit.


❯  python main.py --writer=console  # Outputs the records to the console
❯  python main.py --writer=file  --folder="~"  # Outputs the records to a file in the HOME directory

Running with Docker

The following commands will run the script and output the CO2 records in a file in an /output folder in the current working directory.

❯ mkdir output
❯ docker build -t co2-tracker-docker .
❯ docker run -v "$(pwd)"/output:/app/output co2-tracker-docker

Potential next steps

• Fetch data from another API for redundancy
• Allow for a more frequent run frequency (e.g. fetching data every hour instead of every day)
• Implement new writer classes (e.g. write to a DB) so the data is more easily usable