Digi Connect IT 4 User Manual page 625

Applications
2. Determine the path to the serial port:
# ls /dev/serial/
by-id by-path
#
3. At the shell prompt, use the python command with no parameters to enter an interactive
Python session:
# python
Python 3.10.1 (main, Mar 30 2023, 23:47:13) [GCC 11.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>
4. Import the serial module:
>>> import serial
>>>
5. You can now perform operations on the serial port. For example, to write a message to the
serial port:
>>> s = serial.Serial("/dev/serial/port1", 115200)
>>> s.write(b"Hello from serial port")
26
>>>
6. Use Ctrl-D to exit the Python session. You can also exit the session using exit() or quit().
Use the Paho MQTT python library
Your Connect IT 4 device includes support for the Paho MQTT python library. MQTT is a lightweight
messaging protocol used to communicate with various applications including cloud-based applications
such as Amazon Web Services and Microsoft Azure. The following is example code that reads CPU and
RAM usage on the device, updates the device firmware, then publishes information about DHCP
clients and system information to the MQTT server at 192.168.1.100. The MQTT server IP is
configurable.
"""
MQTT client example:
- Reporting some device metrics from runt
- Reporting DHCP clients
- Firmware update feature (simple implementation, read TODO in cmd_fwupdate)
"""
import sys
import time
import paho.mqtt.client as mqtt
import json
from acl import runt, config
from http import HTTPStatus
import urllib.request
import tempfile
import os
from digidevice import cli
Digi Connect IT® 4 User Guide
by-usb port1
Develop Python applications
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