当数据库只能通过jumphost访问时，如何通过Python连接到MySQL

Question

我有一个MySQL数据库，只能通过一个跳转主机访问。我们尝试访问MySQL的拓扑如下所示

客户端主机-> jumphost -> MySQL

通过使用以下命令ssh -At -L 3306的SSL端口转发来访问用户: MySQL :3306user@jumphost

创建隧道后，在主机为本地主机、端口为3306的情况下，从运行在客户机主机上的工作台成功连接到MySQL。

但是，如果我试图通过MySQL的pymysql模块使用相同的连接属性(主机:本地主机，端口: 3306)访问MySQL，则会出现以下错误：(2003，"Can't connect to mysql server on ' localhost‘(Errno99 Cannot assign requested )“)

代码详细信息：

import pymysql
import pandas

def getQueryResult(query):
    host = 'localhost';
    password = 'something';
    database = 'test';

    conn = pymysql.connect(host=host, port=int(3306), user="someuser", passwd=password, db=database);
    df = pandas.read_sql_query(query, conn);
    conn.close();
    return df;

我们希望连接能够成功建立，但是我们得到了一个跟踪错误

OSErrorTraceback (most recent call last)
/opt/conda/lib/python3.6/site-packages/pymysql/connections.py in connect(self, sock)
    957                                 (self.host, self.port), self.connect_timeout,
--> 958                                 **kwargs)
    959                             break

/opt/conda/lib/python3.6/socket.py in create_connection(address, timeout, source_address)
    723     if err is not None:
--> 724         raise err
    725     else:

/opt/conda/lib/python3.6/socket.py in create_connection(address, timeout, source_address)
    712                 sock.bind(source_address)
--> 713             sock.connect(sa)
    714             # Break explicitly a reference cycle

OSError: [Errno 99] Cannot assign requested address

During handling of the above exception, another exception occurred:

My Code callstack:省略这些框架

/opt/conda/lib/python3.6/site-packages/pymysql/__init__.py in Connect(*args, **kwargs)
     88     """
     89     from .connections import Connection
---> 90     return Connection(*args, **kwargs)
     91 
     92 from . import connections as _orig_conn

/opt/conda/lib/python3.6/site-packages/pymysql/connections.py in __init__(self, host, user, password, database, port, unix_socket, charset, sql_mode, read_default_file, conv, use_unicode, client_flag, cursorclass, init_command, connect_timeout, ssl, read_default_group, compress, named_pipe, no_delay, autocommit, db, passwd, local_infile, max_allowed_packet, defer_connect, auth_plugin_map, read_timeout, write_timeout, bind_address, binary_prefix)
    702             self._sock = None
    703         else:
--> 704             self.connect()
    705 
    706     def _create_ssl_ctx(self, sslp):

/opt/conda/lib/python3.6/site-packages/pymysql/connections.py in connect(self, sock)
   1003                 exc.traceback = traceback.format_exc()
   1004                 if DEBUG: print(exc.traceback)
-> 1005                 raise exc
   1006 
   1007             # If e is neither DatabaseError or IOError, It's a bug.

OperationalError: (2003, "Can't connect to MySQL server on 'localhost' ([Errno 99] Cannot assign requested address)")

Answer 1

也许您可以使用python中的SSH隧道，如下所示：https://medium.com/@amirziai/query-your-database-over-an-ssh-tunnel-with-pandas-603ce49b35a1