ampli/py/util.py

import psycopg2 as pg
from configparser import ConfigParser
import pandas.io.sql as psql

def config(filename='database.ini', section='postgresql'):
    """Config parser from http://www.postgresqltutorial.com/postgresql-python/connect/"""
    # create a parser
    parser = ConfigParser()
    # read config file
    parser.read(filename)
 
    # get section, default to postgresql
    db = {}
    if parser.has_section(section):
        params = parser.items(section)
        for param in params:
            db[param[0]] = param[1]
    else:
        raise Exception('Section {0} not found in the {1} file'.format(section, filename))
 
    return db

def getQuery(query, qparams = []):
    """
    Get single query
    """
    conn = False

    try:
        params = config()

        print("Connecting to database")

        conn = pg.connect(**params)
        cur = conn.cursor()

        # Get table
        dataframe = psql.read_sql(query, conn, params = qparams)

        cur.close()

        return dataframe

    except (Exception, pg.DatabaseError) as error:
        print(error)
        return None

    finally:
        if conn is not False:
            conn.close()
            print('Database connection closed')

if __name__ == "__main__":
    dv = getQuery('SELECT version()').version[0]
    print('PostgreSQL database version:')
    print(dv)