Fix MQTT re-subscription logic (#18953)

* Fix MQTT re-subscription logic

* Cleanup

* Lint

* Fix
This commit is contained in:
Otto Winter 2018-12-03 19:16:58 +01:00 committed by GitHub
parent 111a3254fb
commit c8d92ce907
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@ -5,45 +5,90 @@ For more details about this component, please refer to the documentation at
https://home-assistant.io/components/mqtt/
"""
import logging
from typing import Any, Callable, Dict, Optional
import attr
from homeassistant.components import mqtt
from homeassistant.components.mqtt import DEFAULT_QOS
from homeassistant.loader import bind_hass
from homeassistant.components.mqtt import DEFAULT_QOS, MessageCallbackType
from homeassistant.helpers.typing import HomeAssistantType
from homeassistant.loader import bind_hass
_LOGGER = logging.getLogger(__name__)
@attr.s(slots=True)
class EntitySubscription:
"""Class to hold data about an active entity topic subscription."""
topic = attr.ib(type=str)
message_callback = attr.ib(type=MessageCallbackType)
unsubscribe_callback = attr.ib(type=Optional[Callable[[], None]])
qos = attr.ib(type=int, default=0)
encoding = attr.ib(type=str, default='utf-8')
async def resubscribe_if_necessary(self, hass, other):
"""Re-subscribe to the new topic if necessary."""
if not self._should_resubscribe(other):
return
if other is not None and other.unsubscribe_callback is not None:
other.unsubscribe_callback()
if self.topic is None:
# We were asked to remove the subscription or not to create it
return
self.unsubscribe_callback = await mqtt.async_subscribe(
hass, self.topic, self.message_callback,
self.qos, self.encoding
)
def _should_resubscribe(self, other):
"""Check if we should re-subscribe to the topic using the old state."""
if other is None:
return True
return (self.topic, self.qos, self.encoding) != \
(other.topic, other.qos, other.encoding)
@bind_hass
async def async_subscribe_topics(hass: HomeAssistantType, sub_state: dict,
topics: dict):
async def async_subscribe_topics(hass: HomeAssistantType,
new_state: Optional[Dict[str,
EntitySubscription]],
topics: Dict[str, Any]):
"""(Re)Subscribe to a set of MQTT topics.
State is kept in sub_state.
State is kept in sub_state and a dictionary mapping from the subscription
key to the subscription state.
Please note that the sub state must not be shared between multiple
sets of topics. Every call to async_subscribe_topics must always
contain _all_ the topics the subscription state should manage.
"""
cur_state = sub_state if sub_state is not None else {}
sub_state = {}
for key in topics:
topic = topics[key].get('topic', None)
msg_callback = topics[key].get('msg_callback', None)
qos = topics[key].get('qos', DEFAULT_QOS)
encoding = topics[key].get('encoding', 'utf-8')
topic = (topic, msg_callback, qos, encoding)
(cur_topic, unsub) = cur_state.pop(
key, ((None, None, None, None), None))
current_subscriptions = new_state if new_state is not None else {}
new_state = {}
for key, value in topics.items():
# Extract the new requested subscription
requested = EntitySubscription(
topic=value.get('topic', None),
message_callback=value.get('msg_callback', None),
unsubscribe_callback=None,
qos=value.get('qos', DEFAULT_QOS),
encoding=value.get('encoding', 'utf-8'),
)
# Get the current subscription state
current = current_subscriptions.pop(key, None)
await requested.resubscribe_if_necessary(hass, current)
new_state[key] = requested
if topic != cur_topic and topic[0] is not None:
if unsub is not None:
unsub()
unsub = await mqtt.async_subscribe(
hass, topic[0], topic[1], topic[2], topic[3])
sub_state[key] = (topic, unsub)
# Go through all remaining subscriptions and unsubscribe them
for remaining in current_subscriptions.values():
if remaining.unsubscribe_callback is not None:
remaining.unsubscribe_callback()
for key, (topic, unsub) in list(cur_state.items()):
if unsub is not None:
unsub()
return sub_state
return new_state
@bind_hass