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Configure TCP socket to reduce latency #1683

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merged 6 commits into from
Oct 30, 2023
Merged

Configure TCP socket to reduce latency #1683

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b73fc87
Configure TCP socket to reduce latency
faisal-shah Oct 19, 2023
3aa9047
Make tune TCP for low latency optional
faisal-shah Oct 25, 2023
9bd4b8c
Move os check into __init__
faisal-shah Oct 27, 2023
306051c
Add docstrings
faisal-shah Oct 27, 2023
405fdf3
Add Bus class documentation to docs/interfaces
faisal-shah Oct 28, 2023
b0af0da
Update changelog
faisal-shah Oct 29, 2023
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15 changes: 14 additions & 1 deletion can/interfaces/socketcand/socketcand.py
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
http://www.domologic.de
"""
import logging
import os
import select
import socket
import time
Expand Down Expand Up @@ -75,10 +76,13 @@ def connect_to_server(s, host, port):


class SocketCanDaemonBus(can.BusABC):
def __init__(self, channel, host, port, can_filters=None, **kwargs):
def __init__(self, channel, host, port, tcp_tune=False, can_filters=None, **kwargs):
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It would be nice if you could add a proper docstring like

python-can/can/interfaces/socketcan/socketcan.py

Line 621 in 38c4dc4

"""Creates a new socketcan bus.

The socketcand interface API is not really well documented in doc/interfaces/socketcand.rst

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Alrighty, added docstrings to public methods of the Bus object.

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Awesome, thanks! You can see the docs for your PR here, your changes do not show up yet.

You need to update socketcand.rst.

Add something like

.. autoclass:: can.interfaces.socketcand.SocketCanDaemonBus
   :show-inheritance:
   :member-order: bysource
   :members:

You can build the docs locally with python -m sphinx -Wan --keep-going doc build.

self.__host = host
self.__port = port
self.__tcp_tune = tcp_tune
self.__socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
if self.__tcp_tune:
self.__socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
self.__message_buffer = deque()
self.__receive_buffer = "" # i know string is not the most efficient here
self.channel = channel
Expand Down Expand Up @@ -120,6 +124,9 @@ def _recv_internal(self, timeout):
ascii_msg = self.__socket.recv(1024).decode(
"ascii"
) # may contain multiple messages
if os.name != "nt":
if self.__tcp_tune:
self.__socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_QUICKACK, 1)
self.__receive_buffer += ascii_msg
log.debug(f"Received Ascii Message: {ascii_msg}")
buffer_view = self.__receive_buffer
Expand Down Expand Up @@ -173,9 +180,15 @@ def _recv_internal(self, timeout):
def _tcp_send(self, msg: str):
log.debug(f"Sending TCP Message: '{msg}'")
self.__socket.sendall(msg.encode("ascii"))
if os.name != "nt":
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You could move the OS check into __init__ and warn the user, if the parameter was set on windows. Set self.__tcp_tune = False on Windows and ignore the user input.

if self.__tcp_tune:
self.__socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_QUICKACK, 1)

def _expect_msg(self, msg):
ascii_msg = self.__socket.recv(256).decode("ascii")
if os.name != "nt":
if self.__tcp_tune:
self.__socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_QUICKACK, 1)
if not ascii_msg == msg:
raise can.CanError(f"{msg} message expected!")

Expand Down