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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.

Variable

Description

Purpose

HYDRA_URI

Full Hydra (PostgreSQL-compatible) connection string from the Elestio service overview

Provides all credentials and connection details in a single URI

A typical URI format looks like:

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

You can find thesethe valuesdetails needed in the URI from the Elestio dashboardservice foroverview yourdetails. HydraCopy service.and replace the variables carefully in the URI example provided above.

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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

Create a file called hydra.py and paste the following code:

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

Navigate to the folder where hydra.py is saved and run:

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
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