I have a Lopy board that collects the sensor's data over serial and logs them to the local SD card and then publishes the data to the database using the MQTT protocol. Most of the time the mqtt works properly, but sometimes it was errored out (I don't know what does exactly the error message mean.). Below is the error message, I print the raw data on REPL every second and log the 5-min average. The error often happened after logging the data to the SD card.
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Raw:b'000.010,2.0,+27.2,031,1016.3,00,*01528\r\n', length:45
Raw:b'000.010,2.0,+27.2,031,1016.3,00,*01528\r\n', length:45
LOGGED: 2019-11-26 16:30:00,EST,9,0,2.0,27.2,31,1016.3,00,V
Traceback (most recent call last):
File "main.py", line 223, in <module>
File "/flash/lib/mqtt.py", line 122, in publish
OSError: [Errno 104] ECONNRESET
Pycom MicroPython 1.20.0.rc13 [v1.9.4-94bb382] on 2019-08-22; LoPy4 with ESP32
Type "help()" for more information.
>>>
>>>
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self.sock.write(pkt, i + 1)
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0x4 b'30:4f:00:00'
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0x4 b'30:52:00:00'
I had tried to add 50 ms delay to see if it solve the issue, but no help.
If you have any clues or instructions that can address this issue, please let me know! Thank you in advance.
I also copy the MQTT library that I used for my project.
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#!/usr/bin/env python
#
# Copyright (c) 2019, Pycom Limited.
#
# This software is licensed under the GNU GPL version 3 or any
# later version, with permitted additional terms. For more information
# see the Pycom Licence v1.0 document supplied with this file, or
# available at https://www.pycom.io/opensource/licensing
#
import usocket as socket
import ustruct as struct
import time
from ubinascii import hexlify
class MQTTException(Exception):
pass
class MQTTClient:
def __init__(self, client_id, server, port=0, user=None, password=None, keepalive=0,
ssl=False, ssl_params={}):
if port == 0:
port = 8883 if ssl else 1883
self.client_id = client_id
self.sock = None
self.addr = socket.getaddrinfo(server, port)[0][-1]
self.ssl = ssl
self.ssl_params = ssl_params
self.pid = 0
self.cb = None
self.user = user
self.pswd = password
self.keepalive = keepalive
self.lw_topic = None
self.lw_msg = None
self.lw_qos = 0
self.lw_retain = False
def _send_str(self, s):
self.sock.write(struct.pack("!H", len(s)))
self.sock.write(s)
def _recv_len(self):
n = 0
sh = 0
while 1:
b = self.sock.read(1)[0]
n |= (b & 0x7f) << sh
if not b & 0x80:
return n
sh += 7
def set_callback(self, f):
self.cb = f
def set_last_will(self, topic, msg, retain=False, qos=0):
assert 0 <= qos <= 2
assert topic
self.lw_topic = topic
self.lw_msg = msg
self.lw_qos = qos
self.lw_retain = retain
def connect(self, clean_session=True):
self.sock = socket.socket()
self.sock.connect(self.addr)
if self.ssl:
import ussl
self.sock = ussl.wrap_socket(self.sock, **self.ssl_params)
msg = bytearray(b"\x10\0\0\x04MQTT\x04\x02\0\0")
msg[1] = 10 + 2 + len(self.client_id)
msg[9] = clean_session << 1
if self.user is not None:
msg[1] += 2 + len(self.user) + 2 + len(self.pswd)
msg[9] |= 0xC0
if self.keepalive:
assert self.keepalive < 65536
msg[10] |= self.keepalive >> 8
msg[11] |= self.keepalive & 0x00FF
if self.lw_topic:
msg[1] += 2 + len(self.lw_topic) + 2 + len(self.lw_msg)
msg[9] |= 0x4 | (self.lw_qos & 0x1) << 3 | (self.lw_qos & 0x2) << 3
msg[9] |= self.lw_retain << 5
self.sock.write(msg)
#print(hex(len(msg)), hexlify(msg, ":"))
self._send_str(self.client_id)
if self.lw_topic:
self._send_str(self.lw_topic)
self._send_str(self.lw_msg)
if self.user is not None:
self._send_str(self.user)
self._send_str(self.pswd)
resp = self.sock.read(4)
assert resp[0] == 0x20 and resp[1] == 0x02
if resp[3] != 0:
raise MQTTException(resp[3])
return resp[2] & 1
def disconnect(self):
self.sock.write(b"\xe0\0")
self.sock.close()
def ping(self):
self.sock.write(b"\xc0\0")
def publish(self, topic, msg, retain=False, qos=0):
pkt = bytearray(b"\x30\0\0\0")
pkt[0] |= qos << 1 | retain
sz = 2 + len(topic) + len(msg)
if qos > 0:
sz += 2
assert sz < 2097152
i = 1
while sz > 0x7f:
pkt[i] = (sz & 0x7f) | 0x80
sz >>= 7
i += 1
pkt[i] = sz
#print(hex(len(pkt)), hexlify(pkt, ":"))
#time.sleep_ms(50) # add sleep for test
self.sock.write(pkt, i + 1)
#time.sleep_ms(50) # add sleep for test
self._send_str(topic)
if qos > 0:
self.pid += 1
pid = self.pid
struct.pack_into("!H", pkt, 0, pid)
self.sock.write(pkt, 2)
self.sock.write(msg)
if qos == 1:
while 1:
op = self.wait_msg()
if op == 0x40:
sz = self.sock.read(1)
assert sz == b"\x02"
rcv_pid = self.sock.read(2)
rcv_pid = rcv_pid[0] << 8 | rcv_pid[1]
if pid == rcv_pid:
return
elif qos == 2:
assert 0
def subscribe(self, topic, qos=0):
assert self.cb is not None, "Subscribe callback is not set"
pkt = bytearray(b"\x82\0\0\0")
self.pid += 1
struct.pack_into("!BH", pkt, 1, 2 + 2 + len(topic) + 1, self.pid)
#print(hex(len(pkt)), hexlify(pkt, ":"))
self.sock.write(pkt)
self._send_str(topic)
self.sock.write(qos.to_bytes(1, 'little'))
while 1:
op = self.wait_msg()
if op == 0x90:
resp = self.sock.read(4)
#print(resp)
assert resp[1] == pkt[2] and resp[2] == pkt[3]
if resp[3] == 0x80:
raise MQTTException(resp[3])
return
# Wait for a single incoming MQTT message and process it.
# Subscribed messages are delivered to a callback previously
# set by .set_callback() method. Other (internal) MQTT
# messages processed internally.
def wait_msg(self):
res = self.sock.read(1)
self.sock.setblocking(True)
if res is None:
return None
if res == b"":
raise OSError(-1)
if res == b"\xd0": # PINGRESP
sz = self.sock.read(1)[0]
assert sz == 0
return None
op = res[0]
if op & 0xf0 != 0x30:
return op
sz = self._recv_len()
topic_len = self.sock.read(2)
topic_len = (topic_len[0] << 8) | topic_len[1]
topic = self.sock.read(topic_len)
sz -= topic_len + 2
if op & 6:
pid = self.sock.read(2)
pid = pid[0] << 8 | pid[1]
sz -= 2
msg = self.sock.read(sz)
self.cb(topic, msg)
if op & 6 == 2:
pkt = bytearray(b"\x40\x02\0\0")
struct.pack_into("!H", pkt, 2, pid)
self.sock.write(pkt)
elif op & 6 == 4:
assert 0
# Checks whether a pending message from server is available.
# If not, returns immediately with None. Otherwise, does
# the same processing as wait_msg.
def check_msg(self):
self.sock.setblocking(False)
return self.wait_msg()