# 推薦目錄格式, ThemisPool.py & db.cnf 只需要在同級目錄下即可
[your python project]
    |
    |
    |-- util
         |
         |-- db.cnf
         |
         |-- ThemisPool.py

# 導入依賴
# mysql連接基本庫
import pymysql

# 讀取配置文件所需要的庫
import configparser
import os

# 線程管理所需要的庫
import threading


# 創(chuàng)建配置類用戶讀取配置文件
class Config(object):
    def __init__(self, configFileName='db.cnf'):
        file = os.path.join(os.path.dirname(__file__), configFileName)
        self.config = configparser.ConfigParser()
        self.config.read(file)

    def getSections(self):
        return self.config.sections()

    def getOptions(self, section):
        return self.config.options(section)

    def getContent(self, section):
        result = {}
        for option in self.getOptions(section):
            value = self.config.get(section, option)
            result[option] = int(value) if value.isdigit() else value
        return result
 
# 將連接所需要的參數封裝在對象中 
# 依次為: 數據庫密碼、需要連接的庫名、主機地址[默認 localhost]、端口號[默認 3306]、初始化連接數[默認 3]、最大連接數[默認 6]
class parameter(object):
    def __init__(self, password, database, host="localhost",port="3306" user="root", initsize=3, maxsize=6):
        self.host = str(host)
        self.port = int(port)
        self.user = str(user)
        self.password = str(password)
        self.database = str(database)
        self.maxsize = int(maxsize)
        self.initsize = int(initsize)

# 連接池
class ThemisPool(parameter):
    def __init__(self, fileName='db.cnf', configName='mysql'):
        # 加載配置文件, 配置文件名默認為 'db.cnf', 配置標簽默認為 'mysql'
        self.config = Config(fileName).getContent(configName)
        super(ThemisPool, self).__init__(**self.config)
        # 創(chuàng)建隊列作為 池
        self.pool = queue.Queue(maxsize=self.maxsize)
        self.idleSize = self.initsize
        # 創(chuàng)建線程鎖
        self._lock = threading.Lock()
        # 初始化連接池
        for i in range(self.initsize):
            # 創(chuàng)建 初始化連接數 數量的連接放入池中
            self.pool.put(self.createConn())
        # 啟動日志
        print('\033[1;32m ThemisPool connect database {database}, login is {user} \033[0m'.format(database=self.database,
                                                                                 user=self.user))
                                                                          
    # 生產連接
    def createConn(self):
        # 使用mysql基本類 
        # pymysql.connect 參數這里不做解釋,具體請查閱官網 https://pypi.org/project/PyMySQL/
        return pymysql.connect(host=self.host,
                               port=self.port,
                               user=self.user,
                               password=self.password,
                               database=self.database,
                               charset='utf8')
    
    # 獲取連接
    def getConn(self):
        self._lock.acquire()
        try:
            # 如果池中連接夠直接獲取
            if not self.pool.empty():
                self.idleSize -= 1
            else:
                # 否則重新添加新連接
                if self.idleSize < self.maxsize:
                    self.idleSize += 1
                    self.pool.put(self.createConn())
        finally:
            self._lock.release()
            return self.pool.get()
     
    # 釋放連接
    def releaseCon(self, conn=None):
        try:
            self._lock.acquire()
            # 如果池中大于初始值就將多余關閉，否則重新放入池中
            if self.pool.qsize() < self.initsize:
                self.pool.put(conn)
                self.idleSize += 1
            else:
                try:
                    # 取出多余連接并關閉
                    surplus = self.pool.get()
                    surplus.close()
                    del surplus
                    self.idleSize -= 1
                except pymysql.ProgrammingError as e:
                    raise e
        finally:
            self._lock.release()
      
      
    # 拉取數據（查詢）
    # 可用語句類型 (select)
    def fetchone(self, sql):
        themis = None
        cursor = None
        try:
            themis = self.getConn()
            cursor = themis.cursor()
            cursor.execute(sql)
            return cursor.fetchall()
        except pymysql.ProgrammingError as e:
            raise e
        except pymysql.OperationalError as e:
            raise e
        except pymysql.Error as e:
            raise e
        finally:
            cursor.close()
            self.releaseCon(themis)
     
    # 更新
    # 可用語句類型 (insert, update, delete)
    def update(self, sql):
        themis = None
        cursor = None
        try:
            themis = self.getConn()
            cursor = themis.cursor()
            cursor.execute(sql)
            return cursor.lastrowid
        except pymysql.ProgrammingError as e:
            raise e
        except pymysql.OperationalError as e:
            raise e
        except pymysql.Error as e:
            raise e
        finally:
            themis.commit()
            cursor.close()
            self.releaseCon(themis)
            
     # 釋放連接池本身
     def __del__(self):
        try:
            while True:
                conn = self.pool.get_nowait()
            if conn:
                conn.close()
        except queue.Empty:
            pass

[mysql]
host = localhost
user = root
password = 12345678
database = practice
initsize = 3
maxsize = 6

from util.ThemisPool import ThemisPool

# 初始化ThemisPool連接池 (Initialize the ThemisPool connection pool)
db = ThemisPool()

# 查詢拉取數據,函數會直接返回數據 (Query pull data.It returns data directly)
selectSql = "select * from user;"
data = db.fetchone(selectSql)

# 增、刪、改語句, 如果有使用mysql自增長插入的值函數會返回自增長的數據 (insert,upate delete and alter. If there is a value function inserted using mysql self-growth, it will return self-growth data)
insertSql = "insert into user values(null,'user001','123456')"
id = db.update(selectSql)

# myDB.cnf

[mysqlConfig]
host = localhost
user = root
password = 12345678
database = practice
initsize = 3
maxsize = 6

# 使用時
...
db = ThemisPool(fileName='myDB.cnf', configName='mysqlConfig')
...