Component Discovery
This option is only available for built-in components.
Home Assistant has a discovery service running in the background to discover new devices. Whenever a new device is discovered, a SERVICE_DISCOVERED
event will be fired with the found service and the information. The discovery
component has some knowledge about which components handle which type of services and will ensure those are loaded and listening before firing the SERVICE_DISCOVERED
event.
Add discovery instructions
Device discovery for Home Assistant has been extracted into an external library called NetDisco. This library is integrated using the discovery
component and scans the network in intervals for uPnP and zeroconf/mDNS services.
To have your device be discovered, you will have to extend the NetDisco library to be able to find your device. This is done by adding a new discoverable. See the repository for examples of existing discoverable.
Listening to SERVICE_DISCOVERED
events
From your component, you will have to set up the listening for specific services. Given below is an example how one would listen for a discovered AwesomeDevice:
from homeassistant.components.discovery import SERVICE_AWESOMEDEVICE
from homeassistant.helpers import discovery
DOMAIN = 'awesomedevice'
DEPENDENCIES = ['http']
def setup(hass, config):
cfg = config.get(DOMAIN)
def device_discovered(service, info):
""" Called when a Awesome device has been discovered. """
print("Discovered a new Awesome device: {}".format(info))
discovery.listen(
hass, SERVICE_AWESOMEDEVICE, device_discovered)
return True
Auto-loading your component upon discovery
The discovery
component is capable of setting up your components before firing the EVENT_PLATFORM_DISCOVERED
event. To do this you will have to update the SERVICE_HANDLERS
constant in the discovery
component:
SERVICE_AWESOMEDEVICE = 'awesomedevice'
SERVICE_HANDLERS = {
...
SERVICE_AWESOMEDEVICE: ('awesomedevice', None),
}