tessw-publisher

Serial TESS-W MQTT Publisher daemon

Reads TESS-W data though serial port and publishes to an MQTT broker To be used in special environments with little or null radio emissions (no WiFi)

Installation

We will follow an installation example in a virtual environment for a RespberryPi. Using a virtual environment ensures that we don't mess with system Python libraries should we ever mess it up.

Make sure that:

• Raspberry Pi OS (32-bit) Lite is installed,
• You've got a ssh connection and Internet access
• You have Python3 installed.

1. Install Python3 virtual environment support

pi@astroserver:~ $ sudo apt-get install python3-venv

1. Create a virtual environment named env_tessw

pi@astroserver:~ $ python3 -m venv /home/pi/venv_tessw
pi@astroserver:~ $ ls venv_tessw
bin  include  lib  pyvenv.cfg  share

1. Activate the virtual environment

pi@astroserver:~ $ . venv_tessw/bin/activate
(venv_tessw) pi@astroserver:~ $ 

1. Install the tessw-publisher software within the environment with pip3

(venv_tessw) pi@astroserver:~ $  pip3 install --user tessw-publisher

Configuration

The configuration file

1. First, create a subidirectory where to keep the configuration file:

pi@astroserver:~ $ mkdir /home/pi/venv_tessw/etc

1. Then, create a /home/pi/venv_tessw/etc/config.ini file taking the contets below as a template

# ------------------------------------------------------------------------------
# Copyright (c) 2020 Rafael Gonzalez.
#
# See the LICENSE file for details
# ------------------------------------------------------------------------------

#==============================================================================#
#                            Global configuration Data                         #
#==============================================================================#

[global]

# Transmission period, in seconds
# Not reloadable property
T = 60

# Number of photometers sections below (from 1 to 4)
# Sections below are called [phot1] to [phot4]
# Not reloadable property
nphotom = 1

# Number of supervision cycles to declare a photometer offline
# if the photometer does not delvier any data in all of these cycles
# Not reloadable property
ncycles = 3

# component log level (debug, info, warn, error, critical)
# reloadable property
log_level = info

#------------------------------------------------------------------------------#
#                     TESS-W #1 specific configuration Data                    #
#------------------------------------------------------------------------------#

[phot1]

# Write here the true TESS-W MAC address
# Not reloadable property
mac_address = AA:BB:CC:DD:EE:FF

# If old firmware is used, 
# then we need to fill the name and zero point
# parameters below
# Not reloadable property
old_firmware = no

# Unit name. Must match the name assigned by STARS4ALL. 
# Once set, do not change it !!!
# Not reloadable property
name = test1

# Factory-calibrated Zero Point
# if 20.50 is probably uncalibrated
# This is only needed if old_firmware option = yes
# Not reloadable property
zp = 20.50

# Baud rate supported: only 9600
# Not reloadable property
endpoint = serial:/dev/ttyUSB0:9600

# component log level (debug, info, warn, error, critical)
# reloadable property
log_level = info

# log serial protocol messages from/to TESS ?
# reloadable property
log_messages = warn

#==============================================================================#
#                             MQTT configuration Data                          #
#==============================================================================#

[mqtt]

# MQTT Client config

# Broker to connect. Twisted-style endpoint
# Not reloadable property
broker = tcp:test.mosquitto.org:1883

# Username/password credentials
# leave blank if not needed
# non reloadable properies
username = 
password = 

# Keepalive connection (in seconds)
# Not reloadable property
keepalive = 60

# Base topic to publish on
topic = STARS4ALL

# namespace log level (debug, info, warn, error, critical)
# Reloadable property
log_level = info

# MQTT PDUs log level. 
# See all PDU exchanges with 'debug' level. Otherwise, leave it to 'info'
# Reloadable property
log_messages = debug

Running the software

The software can be run in foreground mode in a console for testing purposes. With the virtual environment active just type:

(venv_tessw) pi@astroserver:~ $ tessw --config venv_tessw/etc/config.ini 

And the prpogram will show on console some similar to this. In this case, there was no photometer attached, so it quits.

2020-07-22T07:56:52+0000 [mqtt#info] MQTT Client library version 0.3.9
2020-07-22T07:56:52+0000 [global#info] tessw 0.1.1 on Twisted 20.3.0, Python 3.5
2020-07-22T07:56:52+0000 [supvr#info] starting Supervisor Service
2020-07-22T07:56:52+0000 [phot1#info] starting Photometer Service 1
2020-07-22T07:56:52+0000 [phot1#critical] [Errno 2] could not open port /dev/ttyUSB0: [Errno 2] No such file or directory: '/dev/ttyUSB0'
2020-07-22T07:56:52+0000 [phot1#warn] stopping Photometer Service 1
2020-07-22T07:56:52+0000 [supvr#warn] Will stop the reactor asap.
2020-07-22T07:56:52+0000 [mqttS#info] starting MQTT Client Service
2020-07-22T07:56:52+0000 [mqtt.client.factory.MQTTFactory#info] Starting factory <mqtt.client.factory.MQTTFactory object at 0x75e9c9b0>
2020-07-22T07:56:52+0000 [supvr#info] Getting info from all photometers
2020-07-22T07:56:53+0000 [-] Main loop terminated.

However, it has been designed to run as a systemd service. The following section describes how to create this systemd service.

The systemd file

Place a file named tesswd.service under /lib/systemd/system with the following contents:

[Unit]
Description=Serial TESS-W MQTT Publisher daemon
Documentation=https://github.com/STARS4ALL/tessw-publisher

[Service]
Type=simple
User=pi
KillMode=process
ExecStart=/home/pi/venv_tessw/bin/python3 -m tessw --config /home/pi/venv_tessw/etc/tessw/config.ini --log-file /home/pi/venv_tessw/log/tessw.log
ExecReload=/bin/kill -s HUP -- $MAINPID
EnvironmentFile=/home/pi/tessw.env

[Install]
WantedBy=multi-user.target

The environment file

Create a /home/pi/tessw.env file with the following contents:

PATH=/home/pi/venv_tessw/bin:/usr/local/bin:/usr/bin:/bin
PYTHONIOENCODING=utf-8
VIRTUAL_ENV=/home/pi/venv_tessw/

The logrotate file

1. Create a subidirectory in the virtual environment where to keep log files:

pi@astroserver:~ $ mkdir /home/pi/venv_tessw/log

1. As user root, create a /etc/logrotate.d/tessw file with a log rotation specification in order to manage daily log files that rotate automatically with the logrotate utility, keeping the last 30 days.

/home/pi/venv_tessw/log/tessw.log {
	daily
	dateext
	rotate 30
	missingok
	notifempty
	copytruncate
}