MQTT Logger (tested on Ubuntu 18.04.1)

Install dependencies

• Python 3.7 (needed for time.time_ns()); make sure this is the default python, or start env with it
• Paho python library: pip3 install paho-mqtt

Create the topic handlers

Edit topic_handlers to add the functions that will receive the messages on the subscribed topics and convert them to the format you want to log.

The function handler name for a topic is derived from the topic name by replacing '/' by '_'. E.g.:

• topic /topic/vio/camera_pixel_pixel should have a handler named _topic_vio_camera_pixel_pixel()

Message topic handlers receive two arguments: the logger handle and the message received (see example handlers).

Start the logger

To start the logger, make sure to give execute permissions to logger.py.

Usage:

./logger.py [-h] [-s MQTTSERVER] [-f LOGFILE] [-t TOPICS]

optional arguments:
  -h, --help     show this help message and exit
  -s MQTTSERVER  MQTT Server; default=oz.andrew.cmu.edu
  -f LOGFILE     Log file; default=vio.log
  -t TOPICS      Subscribe topics; multiple -t are allowed;
                 default=['/topic/vio/camera_pixel_pixel']

Note: multiple topics can be given as argument. e.g.: -t topic1 -t topic2 -t topic3

Startup script

The script log_fixed_camera_solver.sh