Script que utiliza psycopg2 para conectarse a una base de datos postgres.

postgres_conn.py

import traceback
import munch
import psycopg2
import sys

DEBUG_QUERYS = False

def row_to_dict(cursor, row):
    x = {}
    for key, col in enumerate(cursor.description):
        x[col[0]] = row[key]
    return x

def dict_to_object(d):
    return munch.munchify(d)

def get_connection(**kwargs):
    host = kwargs['host']
    port = kwargs['port']
    dbname = kwargs['dbname']
    user = kwargs['user']
    password = kwargs['password']
    conn_string = "host='%s' port='%s' dbname='%s' user='%s' password='%s'" % (host, port, dbname, user, password)
    return psycopg2.connect(conn_string)

def fetch_all(conn, query):
    cursor = conn.cursor()
    try:
        print(query) if DEBUG_QUERYS else None
        cursor.execute(query)
        rows = cursor.fetchall()
        D = [row_to_dict(cursor, row) for row in rows]
        D = [dict_to_object(d) for d in D]
        return D
    except:
        traceback.print_exc()
        return []
    finally:
        cursor.close()

def fetch_first(conn, query):
    D = fetch_all(conn, query)
    if len(D) != 0:
        return D[0]
    else:
        return None
        
if __name__ == '__main__':
    conn = get_connection(host='x.x.x.x', port='xxxx', dbname='xxx', user='xxx', password='xxx')
    if conn is None:
        print('No se pudo conectar a la base de datos')
        exit(-1)

    conn.autocommit = False
    try:
        # Realizar trabajo.
        conn.commit()
    except:
        # Error.
        sys.stderr.write('rollback ...')
        traceback.print_exc()
        conn.rollback()
    finally:
        conn.close()