ChargeSync EV Charging Station

Presented at PGMeetup Helsinki on January 28, 2026

• Meetup Event: https://www.meetup.com/helsinki-postgresql-meetup/events/312404579/
• Slides: https://docs.google.com/presentation/d/1uW7cfhSDwW7BLjbrP_by7eFtcU_5sFm4GDUK98tpUVE/edit?slide=id.p1#slide=id.p1

This document provides instructions on how to run and test the ChargeSync application.

Prerequisites

This project requires the following tools:

• uv: For managing Python dependencies and running the worker.
• Docker: For running the PostgreSQL database.

Prepare the Database

Ensure you have Docker installed and running.

1. Start the PostgreSQL Database:

   docker run --name chargesync-db -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 -d postgres:latest

2. Initialize the Database Schema:

   docker exec -i chargesync-db psql -U postgres -d postgres < init.sql

3. Seeding the Database

   docker exec -i chargesync-db psql -U postgres -d postgres < seed.sql

4. Start the Hardware Controller Worker:

   uv run worker.py

   The worker will start listening for database notifications from new reservations.

How to Demonstrate

1. Start a psql prompt:

   docker exec -ti chargesync-db psql -U postgres -d postgres

2. Search for a charger:

   -- Show the auto generated search vector
   SELECT name, search_vector 
   FROM stations 
   WHERE name = 'ChargePoint A';

   -- Search for stations with "coffee"
   SELECT name, location_name, amenities
   FROM stations
   WHERE search_vector @@ to_tsquery('english', 'coffee');
   
   -- Search for "wifi" AND "food" using logic operators
   SELECT id, name, amenities
   FROM stations
   WHERE search_vector @@ to_tsquery('english', 'wifi & food');

3. Book a charger:

   INSERT INTO reservations (charger_id, user_email, booking_period)
   VALUES (
       3, 
       'helsinki.developer@example.com', 
       tsrange('2026-01-27 17:30:00', '2026-01-27 18:30:00')
   );

4. Attempt to double-book same charger:

   INSERT INTO reservations (charger_id, user_email, booking_period)
   VALUES (
       3, 
       'helsinki.hacker@example.com', 
       tsrange('2026-01-27 18:05:00', '2026-01-27 18:20:00')
   );

5. Log usage for a reservation:

   INSERT INTO usage_logs (reservation_id, kwh_used) VALUES (1, 45.50);