I’m using ari-py to listen to channel events successfully but I was wondering if I can also receive an event when a sip client registers with asterisk? Is it something to do with devices?
There is no ability to receive an event when a SIP client registers, the only thing that comes close is subscribing to device state for the device and you will then receive an event when the device becomes reachable and unreachable.
How exactly would that work? I already have an ARI application in place and I want to get notified when clients become available.
ARI provides the ability to subscribe to receive device state[1]. Once subscribed DeviceStateChange events[2] are sent to indicate changes. This can be used to know when a device becomes available.
[1] https://wiki.asterisk.org/wiki/display/AST/Asterisk+18+Applications+REST+API#Asterisk18ApplicationsRESTAPI-subscribe
[2] https://wiki.asterisk.org/wiki/display/AST/Asterisk+18+ManagerEvent_DeviceStateChange