使用 mysql 和烧瓶登录的 Flask-sqlalchemy 损坏管道错误 32

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【中文标题】使用 mysql 和烧瓶登录的 Flask-sqlalchemy 损坏管道错误 32【英文标题】：Flask-sqlalchemy broken pipe error 32 with mysql and flask-login 【发布时间】：2019-10-30 13:45:36 【问题描述】：

在初始页面加载（使用 flask-login 登录屏幕）时，从 mysql 到 flask-sqlalchemy 的管道损坏（错误 32），第二个请求有效。网站将继续工作几个小时，然后再次失败。

通过mysql+pymysql url连接

数据库是 ubuntu 18.04 机器上的本地 mysql 5.7 服务器 网站通过 gunicorn 托管

网站正在使用蓝图。

Flask==1.0.2
Flask-SQLAlchemy==2.4.0
Flask-Login==0.4.1

网站是从： https://blog.miguelgrinberg.com/post/the-flask-mega-tutorial-part-i-hello-world

在 config.py 中 SQLALCHEMY_POOL_RECYCLE=300

来自 mysql 数据库： wait_timeout = 28800

来自/etc/mysql/mysql.conf.d/mysqld.cnf max_allowed_pa​​cket = 100M

从这里的其他线程来看，sqlalchemy 正在执行会话关闭，所以我在 after_request 函数中没有任何内容。

我已经通过以下搜索进入了谷歌的第三页：

flask-sqlalchemy 断管 mysql sqlalchemy 断管

flask-login mysql 破管

2019-06-15 10:48:43,061 错误：/user/login [POST] [in /srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py:1761 出现异常] 11 Traceback（最近一次调用最后一次）： 12 文件“/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py”，第 713 行，在 _write_bytes 13 self._sock.sendall(数据) 14 BrokenPipeError: [Errno 32] 断管

简化网站：

from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager

db = SQLAlchemy()
login = LoginManager()
login.login_view = 'user.login'

def create_app(config_class=Config):
    app = Flask(__name__)
    app.config.from_object(config_class)

    db.init_app(app)
    login.init_app(app)

    from app.main import mod_main
    app.register_blueprint(mod_main, url_prefix='/')

    from app.user import mod_user
    app.register_blueprint(mod_user, url_prefix='/user')

我在 AWS 上的这个网站在 16.04 的 VM 上运行了 2 年，然后我最近迁移到了 18.04 的服务器并升级了我所有的 flask/python 模块。

我还没有通过每个模块版本来确认为什么现在会发生这种行为。

编辑

完整的堆栈跟踪（删除了“ABC”和“XYZ”所在的电子邮件地址和哈希）

2019-06-15 10:48:43,061 ERROR: Exception on /user/login [POST] [in /srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py:1761]
Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py", line 713, in _write_bytes
    self._sock.sendall(data)
BrokenPipeError: [Errno 32] Broken pipe

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1244, in _execute_context
    cursor, statement, parameters, context
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/default.py", line 552, in do_execute
    cursor.execute(statement, parameters)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/cursors.py", line 170, in execute
    result = self._query(query)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/cursors.py", line 328, in _query
    conn.query(q)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py", line 516, in query
    self._execute_command(COMMAND.COM_QUERY, sql)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py", line 771, in _execute_command
    self._write_bytes(packet)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py", line 718, in _write_bytes
    "MySQL server has gone away (%r)" % (e,))
pymysql.err.OperationalError: (2006, "MySQL server has gone away (BrokenPipeError(32, 'Broken pipe'))")

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/srv/troopnet/app/user/routes.py", line 519, in login
    user = User().authenticate(form.email.data, form.password.data).first()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3215, in first
    ret = list(self[0:1])
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3007, in __getitem__
    return list(res)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3317, in __iter__
    return self._execute_and_instances(context)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3342, in _execute_and_instances
    result = conn.execute(querycontext.statement, self._params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 988, in execute
    return meth(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 287, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1107, in _execute_clauseelement
    distilled_params,
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1248, in _execute_context
    e, statement, parameters, cursor, context
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1466, in _handle_dbapi_exception
    util.raise_from_cause(sqlalchemy_exception, exc_info)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 383, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 128, in reraise
    raise value.with_traceback(tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1244, in _execute_context
    cursor, statement, parameters, context
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/default.py", line 552, in do_execute
    cursor.execute(statement, parameters)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/cursors.py", line 170, in execute
    result = self._query(query)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/cursors.py", line 328, in _query
    conn.query(q)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py", line 516, in query
    self._execute_command(COMMAND.COM_QUERY, sql)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py", line 771, in _execute_command
    self._write_bytes(packet)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/pymysql/connections.py", line 718, in _write_bytes
    "MySQL server has gone away (%r)" % (e,))
sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (2006, "MySQL server has gone away (BrokenPipeError(32, 'Broken pipe'))")
[SQL: SELECT users.id AS users_id, users.email AS users_email, users.password AS users_password 
FROM users 
WHERE users.email = %(email_1)s AND users.password = %(password_1)s 
 LIMIT %(param_1)s]
[parameters: 'email_1': 'ABC', 'password_1': 'XYZ', 'param_1': 1]
(Background on this error at: http://sqlalche.me/e/e3q8)
2019-06-15 10:48:47,064 ERROR: Exception on /user/login [POST] [in /srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py:1761]
Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1177, in _execute_context
    conn = self._revalidate_connection()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 463, in _revalidate_connection
    "Can't reconnect until invalid "
sqlalchemy.exc.InvalidRequestError: Can't reconnect until invalid transaction is rolled back

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/srv/troopnet/app/user/routes.py", line 519, in login
    user = User().authenticate(form.email.data, form.password.data).first()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3215, in first
    ret = list(self[0:1])
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3007, in __getitem__
    return list(res)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3317, in __iter__
    return self._execute_and_instances(context)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3342, in _execute_and_instances
    result = conn.execute(querycontext.statement, self._params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 988, in execute
    return meth(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 287, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1107, in _execute_clauseelement
    distilled_params,
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1182, in _execute_context
    e, util.text_type(statement), parameters, None, None
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1466, in _handle_dbapi_exception
    util.raise_from_cause(sqlalchemy_exception, exc_info)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 383, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 128, in reraise
    raise value.with_traceback(tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1177, in _execute_context
    conn = self._revalidate_connection()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 463, in _revalidate_connection
    "Can't reconnect until invalid "
sqlalchemy.exc.StatementError: (sqlalchemy.exc.InvalidRequestError) Can't reconnect until invalid transaction is rolled back
[SQL: SELECT users.id AS users_id, users.email AS users_email, users.password AS users_password
FROM users 
WHERE users.email = %(email_1)s AND users.password = %(password_1)s 
 LIMIT %(param_1)s]
[parameters: []]
2019-06-15 10:48:50,638 ERROR: Exception on /user/login [POST] [in /srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py:1761]
Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1177, in _execute_context
    conn = self._revalidate_connection()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 463, in _revalidate_connection
    "Can't reconnect until invalid "
sqlalchemy.exc.InvalidRequestError: Can't reconnect until invalid transaction is rolled back

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/srv/troopnet/app/user/routes.py", line 519, in login
    user = User().authenticate(form.email.data, form.password.data).first()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3215, in first
    ret = list(self[0:1])
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3007, in __getitem__
    return list(res)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3317, in __iter__
    return self._execute_and_instances(context)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3342, in _execute_and_instances
    result = conn.execute(querycontext.statement, self._params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 988, in execute
    return meth(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 287, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1107, in _execute_clauseelement
    distilled_params,
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1182, in _execute_context
    e, util.text_type(statement), parameters, None, None
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1466, in _handle_dbapi_exception
    util.raise_from_cause(sqlalchemy_exception, exc_info)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 383, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 128, in reraise
    raise value.with_traceback(tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1177, in _execute_context
    conn = self._revalidate_connection()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 463, in _revalidate_connection
    "Can't reconnect until invalid "
sqlalchemy.exc.StatementError: (sqlalchemy.exc.InvalidRequestError) Can't reconnect until invalid transaction is rolled back
[SQL: SELECT users.id AS users_id, users.email AS users_email, users.password AS users_password
FROM users 
WHERE users.email = %(email_1)s AND users.password = %(password_1)s 
 LIMIT %(param_1)s]
[parameters: []]
2019-06-15 10:48:56,354 ERROR: Exception on /user/login [POST] [in /srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py:1761]
Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1177, in _execute_context
    conn = self._revalidate_connection()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 463, in _revalidate_connection
    "Can't reconnect until invalid "
sqlalchemy.exc.InvalidRequestError: Can't reconnect until invalid transaction is rolled back

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/srv/troopnet/app/user/routes.py", line 519, in login
    user = User().authenticate(form.email.data, form.password.data).first()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3215, in first
    ret = list(self[0:1])
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3007, in __getitem__
    return list(res)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3317, in __iter__
    return self._execute_and_instances(context)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/orm/query.py", line 3342, in _execute_and_instances
    result = conn.execute(querycontext.statement, self._params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 988, in execute
    return meth(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/sql/elements.py", line 287, in _execute_on_connection
    return connection._execute_clauseelement(self, multiparams, params)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1107, in _execute_clauseelement
    distilled_params,
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1182, in _execute_context
    e, util.text_type(statement), parameters, None, None
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1466, in _handle_dbapi_exception
    util.raise_from_cause(sqlalchemy_exception, exc_info)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 383, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb, cause=cause)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/util/compat.py", line 128, in reraise
    raise value.with_traceback(tb)
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 1177, in _execute_context
    conn = self._revalidate_connection()
  File "/srv/troopnet/venv/lib/python3.6/site-packages/sqlalchemy/engine/base.py", line 463, in _revalidate_connection
    "Can't reconnect until invalid "
sqlalchemy.exc.StatementError: (sqlalchemy.exc.InvalidRequestError) Can't reconnect until invalid transaction is rolled back
[SQL: SELECT users.id AS users_id, users.email AS users_email, users.password AS users_password
FROM users 
WHERE users.email = %(email_1)s AND users.password = %(password_1)s 
 LIMIT %(param_1)s]
[parameters: []]

【问题讨论】：

connections.py", line 713 正在读取查询结果，奇怪的是这里失败了。什么 PyMYSQL 版本，什么 MySQL 版本？它是一个缓慢的查询吗？你能包括完整的回溯吗？ MySQL 服务器的错误日志中是否有任何内容（也就是它崩溃了）？在没有 SQLAlchemy 或 PyMYSQL 的情况下直接进入 mysql 的相同查询是否可以正常工作？ 添加了完整的堆栈跟踪。明天晚上将尝试手动查询，然后再次使用 pymysql。 MySQL 错误日志：读取通信数据包超时 查询并不慢（实际上在第二篇文章中很好） MySQL 版本：5.7，PyMySQL 版本：0.9.3 这个问题你解决了吗？ 【参考方案1】：

根据您对最近升级依赖项的评论，我认为问题出在 Flask-Login 的版本上。

我在不同但类似的 Flask 构建中遇到了同样的问题（使用相同的依赖项）。 flask_login 0.4.1 版如何处理用户会话存在问题（问题跟踪器here）。

当我升级到以下问题时，问题就消失了：

Flask-Login==0.5.0
Flask==1.1.2

请注意，您可能还需要以下内容（不要安装最新的 1.0.1，因为它在我的情况下不起作用）：

Werkzeug==0.16.1

如果上述方法没有帮助，您可能需要查看以下列表（在我的情况下不起作用）：

https://www.cnblogs.com/lesliexong/p/8654615.html

祝你好运！

【讨论】：

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