Connecting with Python

This guide explains how to connect a Python application to a Hydra database using the psycopg2-binary package. It covers environment setup, configuration, and execution of a simple query to test connectivity.

Variables

To connect to a Hydra database, you only need one environment variable — the connection URI.

A typical URI format looks like:

postgresql://<USER>:<PASSWORD>@<HOST>:<PORT>/<DATABASE>

You can find the details needed in the URI from the Elestio service overview details. Copy and replace the variables carefully in the URI example provided above.

Prerequisites

Install Python

Check if Python is installed:

python --version

If not installed, download it from https://python.org.

Install psycopg2-binary

Install the PostgreSQL driver for Python:

pip install psycopg2-binary

Code

Once all prerequisites are set up, create a new file named hydra.py and add the following code and replace the HYDRA_URI with actual link or in environment setup as you wish:

import psycopg2
import os

def get_db_version():
    try:
        # Use the Hydra URI from environment variable
        connection_uri = os.getenv('HYDRA_URI', 'POSTGRESQL_URI')
        db_connection = psycopg2.connect(connection_uri)
        db_cursor = db_connection.cursor()
        db_cursor.execute('SELECT VERSION()')
        db_version = db_cursor.fetchone()[0]
        return db_version

    except Exception as e:
        print(f"Database connection error: {e}")
        return None

    finally:
        if 'db_cursor' in locals():
            db_cursor.close()
        if 'db_connection' in locals():
            db_connection.close()

def display_version():
    version = get_db_version()
    if version:
        print(f"Connected to Hydra: {version}")

if __name__ == "__main__":
    display_version()

🔐 Tip: Save your URI in an .env file or set it in your terminal session like this:

export HYDRA_URI=postgresql://user:password@host:port/database

To execute the script, open the terminal or command prompt and navigate to the directory where hydra.py. Once in the correct directory, run the script with the command

python hydra.py

If the connection is successful, you’ll see:

Connected to Hydra: PostgreSQL 14.13 (Debian 14.13-1.pgdg120+1) on x86_64-pc-linux-gnu, compiled by gcc (Debian 12.2.0-14) 12.2.0, 64-bit