ConnectionResetError on Pipeline calls

[FodderMK]

Version:
redis-py: 3.3.6
redis server: 4.0.12

Platform:
Linux 4.14.94+ x86_64 (Google Cloud Memorystore)

Description:
After upgrading from v3.2.1 to 3.3.6 I started to get ConnectionResetError exceptions on longer-running instances of my app.

  [...]
  File "/env/local/lib/python3.7/site-packages/redis/client.py", line 3671, in execute
    self.shard_hint)
  File "/env/local/lib/python3.7/site-packages/redis/connection.py", line 1065, in get_connection
    if connection.can_read():
  File "/env/local/lib/python3.7/site-packages/redis/connection.py", line 682, in can_read
    return self._parser.can_read(timeout)
  File "/env/local/lib/python3.7/site-packages/redis/connection.py", line 295, in can_read
    return self._buffer and self._buffer.can_read(timeout)
  File "/env/local/lib/python3.7/site-packages/redis/connection.py", line 205, in can_read
    raise_on_timeout=False)
  File "/env/local/lib/python3.7/site-packages/redis/connection.py", line 173, in _read_from_socket
    data = recv(self._sock, socket_read_size)
  File "/env/local/lib/python3.7/site-packages/redis/_compat.py", line 58, in recv
    return sock.recv(*args, **kwargs)
ConnectionResetError: [Errno 104] Connection reset by peer

I'm initializing my connection with health checks:

redis_client = redis.Redis(
  host=host,
  port=port,
  socket_timeout=10,
  socket_keepalive=True,
  socket_connect_timeout=10,
  retry_on_timeout=True,
  health_check_interval=10,
)

p = redis_client.pipeline()
[...]
result = p.execute()

From what I can tell the path for execute() does a sock.recv() on a stale connection before it tries to do the health check, causing the exception to occur first. Should execute be trying a health check first?

[andymccurdy]

The problem here is that socket.error (or in this case, a subclass of socket.error) is being raised rather than a redis.exceptions.ConnectionError. This translation was lost during the 3.3.0 changes. ConnectionErrors (in the case of testing the health of the socket as this is trying to do) are automatically resolved by the ConnectionPool.

I've re-added the translation and have released 3.3.7. If for some reason you're still seeing issues, please re-open this issue.

[FodderMK]

I'm not seeing these errors any more. Thanks for the fix!

[andymccurdy]

Great, thanks for reporting back!