Load data local in file fails with AttributeError: 'NoneType' object has no attribute 'settimeout' on connection reset #989
Description
Describe the bug
When loading data into a MariaDB database server using the LOAD DATA LOCAL INFILE syntax, if the database server resets the connection with a ConnectionResetError, the PyMySQL client will re-raise it as an OperationalError, and also attempt to send an empty packet to let the server know we're done sending data. When sending that empty packet, PyMySQL encounters the following exception: AttributeError: 'NoneType' object has no attribute 'settimeout'.
Here's the relevant code from connections.py
class LoadLocalFile:
def __init__(self, filename, connection):
self.filename = filename
self.connection = connection
def send_data(self):
"""Send data packets from the local file to the server"""
if not self.connection._sock:
raise err.InterfaceError(0, "")
conn = self.connection
try:
with open(self.filename, "rb") as open_file:
packet_size = min(
conn.max_allowed_packet, 16 * 1024
) # 16KB is efficient enough
while True:
chunk = open_file.read(packet_size)
if not chunk:
break
conn.write_packet(chunk) # DEBUG: raises ConnectionResetError, force closes connection, sets socket to None
except IOError:
raise err.OperationalError(1017, f"Can't find file '{self.filename}'")
finally:
# send the empty packet to signify we are done sending data
conn.write_packet(b"") # DEBUG: raises AttributeError, attempts to call socket.settimeout on a None reference
I added comments in-line prefaced with DEBUG to help explain the situation.
Here's a snippet where we can see the connection is force closed on a ConnectionResetError (which inherits ConnectionError, which is an alias for IOError)
def _write_bytes(self, data):
self._sock.settimeout(self._write_timeout)
try:
self._sock.sendall(data)
except IOError as e:
self._force_close()
raise err.OperationalError(
CR.CR_SERVER_GONE_ERROR, "MySQL server has gone away (%r)" % (e,)
)
Here's force close
def _force_close(self):
"""Close connection without QUIT message"""
if self._sock:
try:
self._sock.close()
except: # noqa
pass
self._sock = None
self._rfile = None
To Reproduce
I'll put this together soon.
Schema:
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Code:
I'll put this together soon.
Expected behavior
Instead of an AttributeError, an OperationalError should be raised. This allows clients to attempt to retry the failure.
Environment
- OS: Ubuntu 18.04 w/ Python 3.8.11
- Server and version: MariaDB 10.3.23 on AWS RDS
- PyMySQL version: 1.0.2
Additional context
Traceback (most recent call last):
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 756, in _write_bytes
self._sock.sendall(data)
ConnectionResetError: [Errno 104] Connection reset by peer
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 1362, in send_data
conn.write_packet(chunk)
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 680, in write_packet
self._write_bytes(data)
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 759, in _write_bytes
raise err.OperationalError(
pymysql.err.OperationalError: (2006, "MySQL server has gone away (ConnectionResetError(104, 'Connection reset by peer'))")
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 1209, in _read_load_local_packet
sender.send_data()
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 1367, in send_data
conn.write_packet(b"")
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 680, in write_packet
self._write_bytes(data)
File "/root/foreman/venv/lib/python3.8/site-packages/pymysql/connections.py", line 754, in _write_bytes
self._sock.settimeout(self._write_timeout)
AttributeError: 'NoneType' object has no attribute 'settimeout'