通过 Python 发布 MQTT：[Errno 101] 网络不可达

Question

我已使用此脚本在本地网络中的 MQTT 代理上测试了我的脚本：

import paho.mqtt.publish as publish

publish.single('some_topic, 'some message', hostname="192.168.1.123")

一切正常。现在我想发布到我获得凭据的实际服务器。遗憾的是，paho MQTT 脚本的所有示例都发布到本地服务器，因此我无法真正模拟我的脚本。我提供的凭据包括用户名、密码和主题。作为“主机名”，我进入了公司服务器的网站。

脚本现在说

import paho.mqtt.publish as publish
import paho.mqtt.client as mqtt

client = mqtt.Client()

client.username_pw_set("given_username",password="given_password")

publish.single("some_topic",'some message',hostname="example.com")

很遗憾，我收到了一个错误。

  File "get_datas.py", line 18, in handle_data
    publish.single("some_topic",msg,hostname="example.com")
  File "/usr/local/lib/python3.6/site-packages/paho/mqtt/publish.py", line 223, in single
    protocol, transport)
  File "/usr/local/lib/python3.6/site-packages/paho/mqtt/publish.py", line 159, in multiple
    client.connect(hostname, port, keepalive)
  File "/usr/local/lib/python3.6/site-packages/paho/mqtt/client.py", line 839, in connect
    return self.reconnect()
  File "/usr/local/lib/python3.6/site-packages/paho/mqtt/client.py", line 962, in reconnect
    sock = socket.create_connection((self._host, self._port), source_address=(self._bind_address, 0))
  File "/usr/local/lib/python3.6/socket.py", line 722, in create_connection
    raise err
  File "/usr/local/lib/python3.6/socket.py", line 713, in create_connection
    sock.connect(sa)
OSError: [Errno 101] Network is unreachable

我写错了吗？

编辑： 好像主机名有问题。我可以通过插入服务器的 IP 地址来解决这个问题，我通过

[11:26:39] $ ping example.com
PING example.com (xx.xxx.xxx.xxx) 56(84) bytes of data.
64 bytes from example.com (xx.xxx.xxx.xxx): icmp_seq=1 ttl=53 time=43.3 ms

Answer 1

1. 您可能错过了提及 url 中的协议部分，例如 tcp://website.io。 websocket tcp 或 ssl 应该正确提及这一点。
2. 还要检查防火墙中的出站流量规则。 sudo ufw status 添加您允许无处不在的通信协议。

Answer 2

我测试了到 website.io:1883 的连接（默认 MQTT 端口）

PS C:\> Test-NetConnection website.io -port 1883                                                                        WARNING: TCP connect to (3.220.104.187 : 1883) failed                                                                   WARNING: Ping to 3.220.104.187 failed with status: TimedOut                                                             

ComputerName           : website.io
RemoteAddress          : 3.220.104.187
RemotePort             : 1883
InterfaceAlias         : Ethernet
SourceAddress          : 192.168.123.165
PingSucceeded          : False
PingReplyDetails (RTT) : 0 ms
TcpTestSucceeded       : False

TCP ping 测试失败。那你确定地址和端口是对的吗？

另外，带有 SSL 的 MQTT（默认 MQTT SSL 端口是 8883）不提供 TCP 响应：

PS C:\> Test-NetConnection website.io -port 8883
WARNING: TCP connect to (3.220.104.187 : 8883) failed
WARNING: Ping to 3.220.104.187 failed with status: TimedOut


ComputerName           : website.io
RemoteAddress          : 3.220.104.187
RemotePort             : 8883
InterfaceAlias         : Ethernet
SourceAddress          : 192.168.123.165
PingSucceeded          : False
PingReplyDetails (RTT) : 0 ms
TcpTestSucceeded       : False

https://www.hivemq.com/public-mqtt-broker/ 是一个公共 MQTT 服务器。那个是可ping通的：

PS C:\> Test-NetConnection broker.hivemq.com -port 1883                                                                                                                                                                                                                                                                                                                 ComputerName     : broker.hivemq.com
RemoteAddress    : 52.29.71.7
RemotePort       : 1883
InterfaceAlias   : Ethernet
SourceAddress    : 192.168.123.165
TcpTestSucceeded : True