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No way to use async service listeners #1286
Description
The problem is demonstrated with this code:
import asyncio
from zeroconf import Zeroconf, ServiceStateChange
from zeroconf.asyncio import AsyncServiceBrowser
def on_service_state_change(zeroconf, service_type, name, state_change):
if state_change == ServiceStateChange.Added:
info = zeroconf.get_service_info(service_type, name)
print(info)
async def browse_services():
zeroconf = Zeroconf()
service_type = "_http._tcp.local." # Replace with the service type you want to browse
browser = AsyncServiceBrowser(zeroconf, service_type, handlers=[on_service_state_change])
try:
await asyncio.Event().wait()
finally:
zeroconf.close()
if __name__ == "__main__":
asyncio.run(browse_services())
This produces this output:
Exception in callback _SelectorDatagramTransport._read_ready()
handle: <Handle _SelectorDatagramTransport._read_ready()>
Traceback (most recent call last):
File "/usr/lib/python3.10/asyncio/events.py", line 80, in _run
self._context.run(self._callback, *self._args)
File "/usr/lib/python3.10/asyncio/selector_events.py", line 1035, in _read_ready
self._protocol.datagram_received(data, addr)
File "src/zeroconf/_listener.py", line 80, in zeroconf._listener.AsyncListener.datagram_received
File "src/zeroconf/_listener.py", line 161, in zeroconf._listener.AsyncListener.datagram_received
File "src/zeroconf/_handlers/record_manager.py", line 162, in zeroconf._handlers.record_manager.RecordManager.async_updates_from_response
File "src/zeroconf/_handlers/record_manager.py", line 71, in zeroconf._handlers.record_manager.RecordManager.async_updates_complete
File "src/zeroconf/_services/browser.py", line 441, in zeroconf._services.browser._ServiceBrowserBase.async_update_records_complete
File "src/zeroconf/_services/browser.py", line 451, in zeroconf._services.browser._ServiceBrowserBase.async_update_records_complete
File "src/zeroconf/_services/browser.py", line 454, in zeroconf._services.browser._ServiceBrowserBase._fire_service_state_changed_event
File "src/zeroconf/_services/browser.py", line 454, in zeroconf._services.browser._ServiceBrowserBase._fire_service_state_changed_event
File "src/zeroconf/_services/browser.py", line 464, in zeroconf._services.browser._ServiceBrowserBase._fire_service_state_changed_event
File "/home/tkcook/.virtualenvs/veeahub/lib/python3.10/site-packages/zeroconf/_services/__init__.py", line 56, in fire
h(**kwargs)
File "/home/tkcook/Scratch/zeroconf_test.py", line 7, in on_service_state_change
info = zeroconf.get_service_info(service_type, name)
File "/home/tkcook/.virtualenvs/veeahub/lib/python3.10/site-packages/zeroconf/_core.py", line 270, in get_service_info
if info.request(self, timeout, question_type):
File "src/zeroconf/_services/info.py", line 752, in zeroconf._services.info.ServiceInfo.request
RuntimeError: Use AsyncServiceInfo.async_request from the event loop
But it is not possible to use async_request (and by implication async_get_service_info) because the handler is not async. There doesn't seem to be any way to register an async handler. I've tried this:
import asyncio
from zeroconf import Zeroconf, ServiceStateChange
from zeroconf.asyncio import AsyncServiceBrowser
class Foo:
async def add_service(self, *args, **kwargs):
print("add_service")
async def remove_service(self, *args, **kwargs):
print("remove_service")
async def update_service(self, *args, **kwargs):
print("update_service")
async def browse_services():
zeroconf = Zeroconf()
service_type = "_http._tcp.local." # Replace with the service type you want to browse
browser = AsyncServiceBrowser(zeroconf, service_type, listener=Foo())
try:
await asyncio.Event().wait()
finally:
zeroconf.close()
if __name__ == "__main__":
asyncio.run(browse_services())
but this still results in:
/home/tkcook/.virtualenvs/veeahub/lib/python3.10/site-packages/zeroconf/_services/__init__.py:56: RuntimeWarning: coroutine 'Foo.add_service' was never awaited
h(**kwargs)
So there doesn't seem to be any way to use zeroconf from within a service listener.
Am I missing something? Is this a defect?
Activity
tomkcook commentedon Oct 19, 2023
For anyone else who comes along, this works:
bdraco commentedon Oct 30, 2023
python-zeroconf/src/zeroconf/_core.py
Line 263 in 461e6c1
get_service_infois the sync version.use
AsyncServiceInfoinsteadfeat: Make async_get_service_info available on the Zeroconf object
feat: make async_get_service_info available on the Zeroconf object