MQTT-System-Monitor (MSM)

MSM is a daemon that periodically reads PC sensors values and publishes them on an MQTT broker. Its main feature is the modularity, obtained with the dynamic loading of sensors: a sensor is simply a Lua script that parses sensors' data.

Building from source

cargo build

The executable will be placed in build/src/msm.

To manually install msm, the systemd service, the default sensors and the default config.yml:

sudo cp msm.service /usr/lib/systemd/system/
sudo mkdir /etc/msm
sudo cp -r default/* /etc/msm/

sudo systemctl enable msm
sudo systemctl start msm

Configuration

The configuration is stored in /etc/msm/config.yml by default, but it is possible to use another path passing it as the first argument of the executable.

A default config.yml is provided in default/config.yml.

The only required setting is mqtt-broker, that must be the address of the MQTT broker.

Other options are described in the default config.yml.

Building a sensor

It is possible to add new sensors simply writing their Lua scripts. For this kind of sensors it is needed to provide the absolute path in the sensors field of the config.

A sensor script have a prebuilt sensor table that must be filled with data that will be published on MQTT. In particular:

sensor.value = "..." --The sensor actual value that will directly published
sensor.debug_message = "..." --A debug message that will be published
sensor.name = "Sensor name" --The sensor extended name
sensor.id = "sensor_id" --The sensor id, cannot contain spaces
sensor.unit = "..." --The unit of the sensor (like %, °C, ...)
sensor.class = "..." --The sensor class, important if you are using an MQTT subscriber

For this sensor the value will be published on the topic:

prefix/client_id/sensor.class/sensor.id

And the debug message on:

prefix/client_id/sensor.class/sensor.id-debug

prefix is read from the config, the default value is mqtt-system-monitor

client_id is read from the config, the default value is the current system hostname

If the homeassistant flag in the config is set to true, a JSON Home Assistant config for this sensor will be periodically published on the topic:

homeassistant/sensor.class/client_id_sensor.id/config

The JSON will be:

{
    "name": "sensor.name",
    "unit_of_measurement": "sensor.unit",
    "device":
    {
        "name": "client_id",
        "model": "client_id",
        "identifiers": "client_id"
    },
    "expire_after": 60,
    "state_topic": "prefix/client_id/sensor.class/sensor.id",
    "unique_id": "client_id_sensor.id"
}

The expire_after value makes sensors unavailable if the system is unreachable.

For sensor.class possible values refere to the Home Assistant documentation.

State

When the daemon goes online, it publishes on

prefix/client_id/state

The value Online, with the relative JSON configuration for Home Assistant, if needed.

When SIGINT or SIGKILL is received the Offline state is published.

License

msm is distributed with a MIT License. You can see LICENSE.md for more info.