import psycopg2
conn = psycopg2.connect(database="ET",
                        user="et_user",
                        password="Serenitas1",
                        host="debian")

def with_connection(f):
    def with_connection_(*args, **kwargs):
        # or use a pool, or a factory function...
        try:
            rv = f(conn, *args, **kwargs)
        except Exception as e:
            conn.rollback()
            raise

        return rv

    return with_connection_

@with_connection
def query_db(conn, sqlstr, params=None, one=True):
    c = conn.cursor()
    if params:
        c.execute(sqlstr, params)
    else:
        c.execute(sqlstr)
    if one:
        return c.fetchone()
    else:
        return c.fetchall()
    c.close()