#!/usr/bin/python
# -*- coding: utf-8 -*-
from __future__ import print_function
import Queue
import pymysql
import logging


LOG = logging.getLogger(__name__)

class ConnectionPool(object):
    # 例項化類的時候建立連線池
    def __init__(self,**kwargs):
        self.rowSize = kwargs.get('size',10)
        self.kwargs = kwargs
        self.conn_queue = Queue.Queue.maxsize(self.rowSize) # 建立一個固定長度的queue佇列
 

        for i in range(self.rowSize):
            # todo 建立連線
            conn = self._create_new_conn(self.kwargs)
            self._put_conn(conn)


    # 連線資料庫 這裡不做上下文管理，因為需要在保持資料庫連線
    def _create_new_conn(self):
        return pymysql.connect(
            host=self.kwargs.get('host','127.0.0.1'
 
),user=self.kwargs.get('user'),
            passwd=self.kwargs.get('password'),port=self.kwargs.get('port',3306),
            db=self.kwargs.get('db')
        )


    # 把資源放入佇列
    def _put_conn(self,conn):
        if conn:
            self.conn_queue.put(conn)


    # 獲取資源
    def _get_conn(self):
        conn = self.conn_queue.get();
        if
 
 conn is None:
            self._create_new_conn()
        return conn

    def exec_sql(self,sql):
        conn = self._get_conn();
        try:
            with conn as cur:
                cur.execute(sql)
                return cur.fetchall()
        except pymysql.ProgrammingError as e:
            LOG.error('execute sql ({0}) error {1}'.format(sql,e))
        except pymysql.OperationalError as e:
            self._create_new_conn()
            raise e
        finally:
            self._put_conn(conn)

    def __del__(self):
        try:
            while True:
                conn = self.conn_queue.get_nowait()
                if conn:
                    conn.close()
        except Queue.Empty:
            pass