I'm trying to connect to two MySQL databases (one local, one remote) at the same time using Python 3.4 but I'm really struggling. Splitting the problem into three:
- Step 1: connect to the local DB. This is working fine using PyMySQL. (MySQLdb isn't compatible with Python 3.4, of course.)
- Step 2: connect to the remote DB (which needs to use SSH). I can get it to work from the Linux command prompt but not from Python... see below.
- Step 3: connect to both at the same time. I think I'm supposed to use a different port for the remote database so that I can have both connections at the same time but I'm out of my depth here! If it's relevant then the two DBs will have different names. And if this question isn't directly related, please tell me and I'll post it separately.
Unfortunately I'm not really starting in the right place for a newbie... once I can get this working I can happily go back to basic Python and SQL but hopefully someone will take pity on me and give me a hand to get started!
For Step 2, my code is below. It seems to be quite close to the sshtunnel example which answers this question Python - SSH Tunnel Setup and MySQL DB Access
import dropbox, pymysql, shlex, shutil, subprocess from sshtunnel import SSHTunnelForwarder import iot_config as cfg def CloseLocalDB(): localcur.close() localdb.close() def CloseRemoteDB(): # Disconnect from the database # remotecur.close() # remotedb.close() # Close the SSH tunnel # ssh.close() print("end of CloseRemoteDB function") def OpenLocalDB(): global localcur, localdb localdb = pymysql.connect(host=cfg.localdbconn['host'], user=cfg.localdbconn['user'], passwd=cfg.localdbconn['passwd'], db=cfg.localdbconn['db']) localcur = localdb.cursor() def OpenRemoteDB(): global remotecur, remotedb with SSHTunnelForwarder( ('my_remote_site', 22), ssh_username = "my_ssh_username", ssh_private_key = "/etc/ssh/my_private_key.ppk", ssh_private_key_password = "my_private_key_password", remote_bind_address = ('127.0.0.1', 3308)) as server: remotedb = None #Following line gives an error if uncommented # remotedb = pymysql.connect(host='127.0.0.1', user='remote_db_user', passwd='remote_db_password', db='remote_db_name', port=server.local_bind_port) #remotecur = remotedb.cursor() # Main program starts here OpenLocalDB() CloseLocalDB() OpenRemoteDB() CloseRemoteDB() This is the error I'm getting:
2016-04-21 19:13:33,487 | ERROR | Secsh channel 0 open FAILED: Connection refused: Connect failed 2016-04-21 19:13:33,553 | ERROR | In #1 <-- ('127.0.0.1', 60591) to ('127.0.0.1', 3308) failed: ChannelException(2, 'Connect failed') ---------------------------------------- Exception happened during processing of request from ('127.0.0.1', 60591) Traceback (most recent call last): File "/usr/local/lib/python3.4/dist-packages/sshtunnel.py", line 286, in handle src_address) File "/usr/local/lib/python3.4/dist-packages/paramiko/transport.py", line 834, in open_channel raise e paramiko.ssh_exception.ChannelException: (2, 'Connect failed') During handling of the above exception, another exception occurred: Traceback (most recent call last): File "/usr/lib/python3.4/socketserver.py", line 613, in process_request_thread self.finish_request(request, client_address) File "/usr/lib/python3.4/socketserver.py", line 344, in finish_request self.RequestHandlerClass(request, client_address, self) File "/usr/lib/python3.4/socketserver.py", line 669, in __init__ self.handle() File "/usr/local/lib/python3.4/dist-packages/sshtunnel.py", line 296, in handle raise HandlerSSHTunnelForwarderError(msg) sshtunnel.HandlerSSHTunnelForwarderError: In #1 <-- ('127.0.0.1', 60591) to ('127.0.0.1', 3308) failed: ChannelException(2, 'Connect failed') ---------------------------------------- Traceback (most recent call last): File "/home/pi/Documents/iot_pm2/iot_ssh_example_for_help.py", line 38, in <module> OpenRemoteDB() File "/home/pi/Documents/iot_pm2/iot_ssh_example_for_help.py", line 32, in OpenRemoteDB remotedb = pymysql.connect(host='127.0.0.1', user='remote_db_user', passwd='remote_db_password', db='remote_db_name', port=server.local_bind_port) File "/usr/local/lib/python3.4/dist-packages/pymysql/__init__.py", line 88, in Connect return Connection(*args, **kwargs) File "/usr/local/lib/python3.4/dist-packages/pymysql/connections.py", line 678, in __init__ self.connect() File "/usr/local/lib/python3.4/dist-packages/pymysql/connections.py", line 889, in connect self._get_server_information() File "/usr/local/lib/python3.4/dist-packages/pymysql/connections.py", line 1190, in _get_server_information packet = self._read_packet() File "/usr/local/lib/python3.4/dist-packages/pymysql/connections.py", line 945, in _read_packet packet_header = self._read_bytes(4) File "/usr/local/lib/python3.4/dist-packages/pymysql/connections.py", line 981, in _read_bytes 2013, "Lost connection to MySQL server during query") pymysql.err.OperationalError: (2013, 'Lost connection to MySQL server during query') Thanks in advance.