[mqtt from getting started to improving series | 01] quickly build an mqtt test environment from 0 to 1

This is the third of the future of machines 24 An article

The original address ：https://blog.csdn.net/RobotFutures/article/details/125532208

1. mosquitto summary

Eclipse mosquitto It's open source (EPL/EDL Permitted ) The message broker , It has achieved MQTT Protocol version 5.0、3.1.1 and 3.1.mosquito It's lightweight , For all equipment , From low-power single board computer to complete server .

MQTT The protocol provides for the use of publishing / The subscription model is a lightweight way to perform messaging . This makes it suitable for Internet of things messaging , Such as low-power sensors or mobile devices , Such as mobile phone 、 Embedded computer or microcontroller .

mosquito to The project also provides an implementation for MQTT Of the client C library , And very popular mosquito to_pub and mosquito to_sub Command line MQTT The client .

2. download MQTT Deploy software

Download address ： Portal

3. Quick start mosquitto

3.1 start-up mqtt broker

Start the command line tool , Switch to mosquitto The installation directory , Execute the following command , start-up broker

mosquitto.exe -v

The default open port is 1883.

The details of the order are as follows ：

mosquitto [-c config file] [ -d | --daemon ] [-p port number] [-v]

-c Specify the profile path , The default configuration path is... Under the installation directory mosquitto.conf
-d Start up and run in the background
-p Designated port , The default is 1883
-v Turn on log output

matters needing attention ： If you don't specify a profile , Only... Is supported by default 127.0.0.1 Local loopback network card connection , If you want to connect LAN or extranet clients , Then be sure to specify the configuration file mosquitto.conf:

listener 1883
allow_anonymous true  #  Allow anonymous access 

The start command is as follows ：

mosquitto.exe -c mosquitto.conf -v

Due to computer configuration problems , Here we use the custom port test

#mosquitto.exe -v -p 6969
1647942133: mosquitto version 2.0.14 starting
1647942133: Using default config.
1647942133: Starting in local only mode. Connections will only be possible from clients running on this machine.
1647942133: Create a configuration file which defines a listener to allow remote access.
1647942133: For more details see https://mosquitto.org/documentation/authentication-methods/
1647942133: Opening ipv4 listen socket on port 6969.
1647942133: Opening ipv6 listen socket on port 6969.
1647942133: mosquitto version 2.0.14 running

3.2 Subscribe to topics

mosquitto_sub.exe -t sensors/temperature -q 1 -p 6969

-t Appoint topic, Here is the sensor temperature value sensors/temperature
-q Appoint qos quality , Here for 1
-p Designated port , Here for 6969

After the execution of the command ,broker The log of is described as follows ：

1647942590: New connection from 127.0.0.1:1746 on port 6969.
1647942590: New client connected from 127.0.0.1:1746 as auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0 (p2, c1, k60).
1647942590: No will message specified.
1647942590: Sending CONNACK to auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0 (0, 0)
1647942591: Received SUBSCRIBE from auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0
1647942591:     sensors/temperature (QoS 1)
1647942591: auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0 1 sensors/temperature
1647942591: Sending SUBACK to auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0

auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0 - After successful connection ,broker Assigned session ID
CONNACK： Yes Connect Command response
SUBSCRIBE ： Subscription requests initiated by clients
SUBACK ：broker Client side auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0 Of SUBSCRIBE Command feedback

3.3 Release theme

mosquitto_pub.exe -t sensors/temperature -m 32 -q 1 -p 6969

-t Appoint topic, Here is the sensor temperature value sensors/temperature
-q Appoint qos quality , Here for 1
-p Designated port , Here for 6969
-m Specify the message , The message here is 32

After the execution of the command ：

• broker The log output of is as follows

1647942676: New connection from 127.0.0.1:1914 on port 6969.
1647942676: New client connected from 127.0.0.1:1914 as auto-BADB5BE4-8FF4-C9F8-DD05-955CEC58CA3D (p2, c1, k60).
1647942676: No will message specified.
1647942676: Sending CONNACK to auto-BADB5BE4-8FF4-C9F8-DD05-955CEC58CA3D (0, 0)
1647942676: Received PUBLISH from auto-BADB5BE4-8FF4-C9F8-DD05-955CEC58CA3D (d0, q1, r0, m1, 'sensors/temperature', ... (2 bytes))
1647942676: Sending PUBLISH to auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0 (d0, q1, r0, m1, 'sensors/temperature', ... (2 bytes))
1647942676: Sending PUBACK to auto-BADB5BE4-8FF4-C9F8-DD05-955CEC58CA3D (m1, rc0)
1647942676: Received PUBACK from auto-651BD76A-09A1-67FD-1DF9-AF36BEADB2D0 (Mid: 1, RC:0)
1647942676: Received DISCONNECT from auto-BADB5BE4-8FF4-C9F8-DD05-955CEC58CA3D
1647942676: Client auto-BADB5BE4-8FF4-C9F8-DD05-955CEC58CA3D disconnected.

• The output of the subscribed client log is as follows ：

PS E:\Tools\mosquitto> mosquitto_sub.exe -t sensors/temperature -q 1 -p 6969
32

You can see , The subscription client has received the message published by the publisher ： Temperature value 32

3.4 Simple subscription / Publish workflow

4. Problems encountered during the test

4.1 Record mosquitto Port access failure debugging record

• By order mosquitto -v start-up MQTT broker The port opening of is as follows ：

PS X:> netstat -an |findstr "1883"
  TCP    127.0.0.1:1883        0.0.0.0:0              LISTENING
  TCP    [::1]:1883            [::]:0                 LISTENING

• By order mosquitto -c .\mosquitto.conf -v start-up MQTT broker The port opening of is as follows ：

PS C:\Users\25267> netstat -an |findstr "1883"
  TCP    0.0.0.0:1883         0.0.0.0:0              LISTENING
  TCP    192.168.149.108:1883 192.168.149.162:59826  ESTABLISHED
  TCP    [::]:1883             [::]:0                 LISTENING

You can see that when the configuration file is not loaded , Only loopback network card is supported by default .

Write at the end ：

• Blog profile ： focus AIoT field , Chasing the pulse of the future era , Record the technological growth on the way ！
• Column Introduction ： from 0 To 1 Master distributed messaging middleware MQTT Use .
• Face the crowd ： A programmer with basic embedded development experience or above
• Column plan ： Next, we will gradually publish a series of blog posts into artificial intelligence , Coming soon
• Python Zero foundation quick start series
  • Quick start Python Data Science Series
  • Artificial intelligence development environment building series
  • Machine learning series
  • Object detection quick start series
  • Autopilot Simulator AirSim Introductory series
  • Automatic driving object detection series
  • …