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()

        print("Table recieved")

        return dataframe

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

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


def pickleQuery(query, path, qparams=[]):
    dq = getQuery(query, qparams)
    dq.to_pickle(path)
    print("Table pickled")


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