It is possible to send messages from your kervi app when certain conditions occurs. The main concept is that a message can be send to one or more message channels like e-mail and user log. The user log is accessible in the UI and error and warning messages are shown as pop up notifications.

Value messages

You can set warning and error ranges on sensors and other kervi values.

from kervi.application import Application
app = Application()

from kervi.sensors import Sensor
from kervi.devices.sensors.dummy_sensor import DummySensorDeviceDriver

sensor = Sensor("sensor","CPU", DummySensorDeviceDriver())


sensor.add_error_range((0, 10), "low error message", channels=["user_log", "email"])
sensor.add_warning_range((10, 20), "low warning message")
sensor.add_warning_range((80, 90), "high warning message",channels=["user_log", "email"])
sensor.add_error_range((90, 100), "high error message", channels=["user_log", "email"])
sensor.add_normal_range((20, 80), "normal ", channels=["user_log", "email"])

In the example above a series of error and warning ranges are defined. It is the channels parameter that controls where the range messages are send to. Default value for the channels parameter is user_log if the parameter is omitted.

Sending custom messages

You use the Messaging class to send your own messages.

from kervi.messaging import Messaging

Messaging.send_message("My message", level=1)
  • level 1 is error.
  • level 2 is warning.
  • level 3 is normal info.


The message channels are activated via via Kervi configuration. The user log channel is always enabled.


Below is the required configuration for the email message plugin. The plugin will be loaded if enabled is True.

from kervi.application import Application
app = Application({
            "": {
                "enabled": False,
                "smtp": {
                    "sender_name": "Kervi",
                    "sender_address": "",
                    "server": "localhost",
                    "port": "25",
                    "user": "mail_user_name",
                    "password": "mail_user_password",
                    "tls": False