Strange re-connection problem with python-bitcoinrpc

Question

I am using https://github.com/jgarzik/python-bitcoinrpc to access the bitcoin core rpc. I have found a very strange re-connection problem.

from bitcoinrpc.authproxy import AuthServiceProxy, JSONRPCException

# rpc_user and rpc_password are set in the bitcoin.conf file
1. rpc_connection = AuthServiceProxy("http://%s:%s@127.0.0.1:8332"%(rpc_user, rpc_password))
2. best_block_hash = rpc_connection.getbestblockhash()
3. print(rpc_connection.getblock(best_block_hash))

The above code runs well in the python interactive window. However, after a while (for instance 10s), when I run the line2 again, it crashs with following info:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/fangjun/.local/lib/python3.5/site-packages/bitcoinrpc/authproxy.py", line 136, in __call__
    'Content-type': 'application/json'})
  File "/usr/lib/python3.5/http/client.py", line 1106, in request
    self._send_request(method, url, body, headers)
  File "/usr/lib/python3.5/http/client.py", line 1151, in _send_request
    self.endheaders(body)
  File "/usr/lib/python3.5/http/client.py", line 1102, in endheaders
    self._send_output(message_body)
  File "/usr/lib/python3.5/http/client.py", line 936, in _send_output
    self.send(message_body)
  File "/usr/lib/python3.5/http/client.py", line 908, in send
    self.sock.sendall(data)
BrokenPipeError: [Errno 32] Broken pipe

if I reconnect the server again by running line1, then line2 runs well.

It seems I need to run line1 from time to time, but it doesn't make sense. Can some tell me the reason? Thanks.

Answer 1

Both the RPC client and the RPC server have timeouts, if no request or response has been received for X seconds, they will close the connection. By default the timeout is 30 seconds. I believe you are running into the timeout since you wait a while before trying to send another command. By that point, one end has timed out and thus the connection is closed resulting in Broken pipe errors.