公司有一个demo的后端是我用python flask框架写的,出现过几次后端崩了的情况,一开始我以为是参数的问题,写了个异常抛出,没有去查看日志。后面继续崩,我发现事情并不简单,然后就留意了一下日志,发现报错是 pymysql.err.InterfaceError 。好家伙,就是数据库连接的问题啊,后面就百度了一下,发现是数据库长时间连接会自动断开,问题找到了,接下来就是解决问题了。
报错详情
117.171.190.84 - - [22/May/2021 23:02:01] "[35m[1mPOST /vs HTTP/1.1[0m" 500 - Traceback (most recent call last): File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 2464, in __call__ return self.wsgi_app(environ, start_response) File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 2450, in wsgi_app response = self.handle_exception(e) File "/home/admin/python3/lib/python3.6/site-packages/flask_cors/extension.py", line 165, in wrapped_function return cors_after_request(app.make_response(f(*args, **kwargs))) File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 1867, in handle_exception reraise(exc_type, exc_value, tb) File "/home/admin/python3/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise raise value File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 2447, in wsgi_app response = self.full_dispatch_request() File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 1952, in full_dispatch_request rv = self.handle_user_exception(e) File "/home/admin/python3/lib/python3.6/site-packages/flask_cors/extension.py", line 165, in wrapped_function return cors_after_request(app.make_response(f(*args, **kwargs))) File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 1821, in handle_user_exception reraise(exc_type, exc_value, tb) File "/home/admin/python3/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise raise value File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 1950, in full_dispatch_request rv = self.dispatch_request() File "/home/admin/python3/lib/python3.6/site-packages/flask/app.py", line 1936, in dispatch_request return self.view_functions[rule.endpoint](**req.view_args) File "/home/admin/demo.py", line 72, in json_vs cursor.execute("select * from t_vs") File "/home/admin/python3/lib/python3.6/site-packages/pymysql/cursors.py", line 148, in execute result = self._query(query) File "/home/admin/python3/lib/python3.6/site-packages/pymysql/cursors.py", line 310, in _query conn.query(q) File "/home/admin/python3/lib/python3.6/site-packages/pymysql/connections.py", line 547, in query self._execute_command(COMMAND.COM_QUERY, sql) File "/home/admin/python3/lib/python3.6/site-packages/pymysql/connections.py", line 793, in _execute_command raise err.InterfaceError(0, "") pymysql.err.InterfaceError: (0, '')
问题找到了,该解决了
def json_vs(): # 访问量接口 global coon coon.ping() cursor = coon.cursor() cursor.execute("select * from t_vs") data = cursor.fetchall() cursor = coon.cursor() sql = "update t_vs set vs=%s where id=1" cursor.execute(sql,data[0][1]+1) data1 = cursor.fetchall() return jsonify(data)
coon = pymysql.connect(host) ## host是你连接数据库的语句 coon 需要替换成你定义的变量 coon.ping() # 在执行sql语句之前加上这个就可以了
这个只是临时解决一下,确保项目能够正常运行。这种方式消耗性能,可以写一个try抛出异常,当有问题的时候再执行coon.ping 或者自己写一个连接池,连接池相对这个方式而已是不会有这个消耗性能的,这个只是临时解决的方案。后面回更新连接池的代码。