用过ＭySQL的应该都知道，ＭySQL默认长链接只能保持8小时，超过后就会自动断开。

在peewee中如何维持长连接呢？

解决方法比较晦涩，需要自定义一个支持重试的mixin，然后自定义一种RetryMySQLDatabase混入mixin

from peewee import * 
from peewee import __exception_wrapper__

class RetryOperationalError(object):

    def execute_sql(self, sql, params=None, commit=True):
        try:
            cursor = super(RetryOperationalError, self).execute_sql(
                sql, params, commit)
        except OperationalError:
            if not self.is_closed():
                self.close()
            with __exception_wrapper__:
                cursor = self.cursor()
                cursor.execute(sql, params or ())
                if commit and not self.in_transaction():
                    self.commit()
        return cursor

class RetryMySQLDatabase(RetryOperationalError, MySQLDatabase):
    pass

之后当作MySQLDatabase正常使用就可以了

XXX_DB = RetryMySQLDatabase(
    'dbname',
    host=MYSQL_HOST,
    port=MYSQL_PORT,
    user='user',
    passwd='pass')