This program has been designed to alert administrators if environmental variables cross certain thresholds, using a Yocto-Meteo station device.

First, install the Yoctopuce SDK for Python available in PyPi repositories :

pip install yoctopuce

Depending on your needs, you might want to install the following dependency in order to send log messages to a Graylog server :

pip install graypy

Clone the repository in a target folder, e.g. /opt, and give ownership to the user whose identity will be used to run the program.

You can launch it by hand, in which case execute a Python3 interpreter targeting main.py.

A skeleton of systemd service descriptor is provided under yoctometeo-alerting.service. You might want to edit the following parameters to suit your install :

• User/Group : must match the aforementionned
• WorkingDirectory/ExecStart : depending on the program path
• StandardOutput/StandardOutput : where the outputs should be directed to, defaults to syslog

The configuration is stored in a JSON-syntax file config.json. A sample skeleton may be found in the repository : sample-config.json. This section will briefly summarize the available options.

The program will automatically perform a check sequence after the expiry of the delay since the last sequence completed. To be expressed in milliseconds.

This section defines the parameters required to send alerts through e-mails.

"mail-server": {
    "host": "smtp.example.tld",
    "port": "465",
    "tls": "yes", // whether using TLS encryption
    "username": "ano.nymous", //leave blank if no authentication is required
    "password": "Azerty",
    "from-address": "yocto@example.tld" // Originating e-mail address, will appear to the recipient
}

This section defines the parameters required to send alerts to a Graylog server. Optional.

"log-server": {
    "host": "log.example.tld",
    "port": 12201
}

This section defines the people who will receive the alerts, with their contact infos. It is an array of objects defined as follow :

"addressees": [
    {
      "name": "****", // Name of the addressee
      "mail": "**@***", // Email address
      "phone-number": "+336XXXXXXXXX" // Phone number
    }
]

This section defines the YoctoMeteo devices used by the program. Here are the different components of this section.

These objects define a module, as a hardware piece of equipment, with the following parameters :

• The hardware ID, which can be found using YoctoPuce SDKs or demo softwares, it is used to uniquely identify a module.
• The host identifier
  • [hostname]:[port] for VirtualHub intallations
  • usb for direct access through USB port (specific instructions to be found thereafter)
• An array of sensor objects, whose description can be found in the next section

{
  "hardware-id": "****",
  "host": "***",
  "sensors": []
}

These objects define a sensor, meaning an environmental variable (not necessarily a separate physical equipment). One must be defined for each variable to be monitored, for each module, with the following parameters :

• The sensor type, to be chosed among the following :
  • temperature
  • humidity
  • pressure
• An array of alert objects, whose description can be found in the next section

{
    "type": "temperature|humidity|pressure",
    "alerts": []
}

These objects define an alert, meaning a threshold which, if crossed, will trigger an alerting action. Sensors can handle multiple alerts, for instance lowlevel e-mail alert for a small overheating, and a hurry SMS alert for a fire-like problem. It must be defined with the following parameters :

• An identifier to remain unique among the program instance
• The vector used to transmit the alert (if a log server has been defined, each and every alert will be forwarded to it), currently supported :
  • E-mail
  • SMS (to be implemented depending on your platform)
• The alert level (used for the logging system), to be chosed among the following, by increasing degree of harm :
  • warning
  • error
  • critical
• The variable can pass below or over the threshold
• The trigger threshold : crossing it in the aforementioned direction will trigger the alert
• The reset threshold : crossing it in the direction opposite to the aforementioned will reset the alert

The interest of this double-threshold mechanism is to introduce a hysteresis, thus avoiding endless alert/end-of-alert messages when the value bounces arround the threshold.

{
    "alert-id": 1,
    "alert-vector": "email",
    "level": "warning",
    "direction": "over",
    "trigger": 25,
    "reset": 22
}

In order for USB access to work for users other than root, you should copy the file 51-yoctopuce_all.rules in the /etc/udev/rules.d directory.