import os
import psycopg2.pool

connection_pool = psycopg2.pool.ThreadedConnectionPool(0, 50,
    dbname='foobar',
    user='foobar',
    password='foobar',
    host=HOST,
    )

class db_conn(object):
    def execute(self, query, params=()):
        self.cur.execute(query, params)
    def execute_fetch(self, query, params=()):
        self.cur.execute(query, params)
        return self.cur.fetchall()
    def execute_fetchone(self, query, params=()):
        self.cur.execute(query, params)
        return self.cur.fetchone()
    def execute_fetch_dict(self, query, params=()):
        self.cur.execute(query, params)
        rows = self.cur.fetchall()
        columns = [d[0] for d in self.cur.description]
        dict_rows = [dict(zip(columns, row)) for row in rows]
        return dict_rows
    def execute_fetchone_dict(self, query, params=()):
        self.cur.execute(query, params)
        row = self.cur.fetchone()
        if row:
            columns = [d[0] for d in self.cur.description]
            dict_row = dict(zip(columns, row))
            return dict_row
    def row_count(self):
        return self.cur.rowcount

    def __enter__(self):
        self.conn = connection_pool.getconn()
        self.cur = self.conn.cursor()
        return self

    def __exit__(self, type, value, traceback):
        if type is None:
            self.conn.commit()
        self.cur.close()
        self.conn.rollback()
        connection_pool.putconn(self.conn)