From ab17b4ab70eee5b4fada5f3d22477df972616c90 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Fri, 2 Oct 2020 07:27:39 -0500
Subject: [PATCH] Simplify template tracking and make it easier to follow
(#41030)
---
homeassistant/helpers/event.py | 134 ++++++++++++++++++++-------------
1 file changed, 81 insertions(+), 53 deletions(-)
diff --git a/homeassistant/helpers/event.py b/homeassistant/helpers/event.py
index 52a43fca3ff..d143ed1d106 100644
--- a/homeassistant/helpers/event.py
+++ b/homeassistant/helpers/event.py
@@ -774,16 +774,65 @@ class _TrackTemplateResultInfo:
"""Force recalculate the template."""
self._refresh(None)
- @callback
- def _event_triggers_template(self, template: Template, event: Event) -> bool:
- """Determine if a template should be re-rendered from an event."""
- entity_id = event.data.get(ATTR_ENTITY_ID)
- return (
- self._info[template].filter(entity_id)
- or event.data.get("new_state") is None
- or event.data.get("old_state") is None
- and self._info[template].filter_lifecycle(entity_id)
- )
+ def _render_template_if_ready(
+ self,
+ track_template_: TrackTemplate,
+ now: datetime,
+ event: Optional[Event],
+ ) -> Union[bool, TrackTemplateResult]:
+ """Re-render the template if conditions match.
+
+ Returns False if the template was not be re-rendered
+
+ Returns True if the template re-rendered and did not
+ change.
+
+ Returns TrackTemplateResult if the template re-render
+ generates a new result.
+ """
+ template = track_template_.template
+
+ if event:
+ info = self._info[template]
+
+ if not self._rate_limit.async_has_timer(
+ template
+ ) and not _event_triggers_rerender(event, info):
+ return False
+
+ if self._rate_limit.async_schedule_action(
+ template,
+ info.rate_limit or track_template_.rate_limit,
+ now,
+ self._refresh,
+ event,
+ ):
+ return False
+
+ _LOGGER.debug(
+ "Template update %s triggered by event: %s",
+ template.template,
+ event,
+ )
+
+ self._rate_limit.async_triggered(template, now)
+ self._info[template] = template.async_render_to_info(track_template_.variables)
+
+ try:
+ result: Union[str, TemplateError] = self._info[template].result()
+ except TemplateError as ex:
+ result = ex
+
+ last_result = self._last_result.get(template)
+
+ # Check to see if the result has changed
+ if result == last_result:
+ return True
+
+ if isinstance(result, TemplateError) and isinstance(last_result, TemplateError):
+ return True
+
+ return TrackTemplateResult(template, last_result, result)
@callback
def _refresh(self, event: Optional[Event]) -> None:
@@ -792,51 +841,13 @@ class _TrackTemplateResultInfo:
now = dt_util.utcnow()
for track_template_ in self._track_templates:
- template = track_template_.template
- if event:
- if not self._rate_limit.async_has_timer(
- template
- ) and not self._event_triggers_template(template, event):
- continue
-
- if self._rate_limit.async_schedule_action(
- template,
- self._info[template].rate_limit or track_template_.rate_limit,
- now,
- self._refresh,
- event,
- ):
- continue
-
- _LOGGER.debug(
- "Template update %s triggered by event: %s",
- template.template,
- event,
- )
-
- self._rate_limit.async_triggered(template, now)
- self._info[template] = template.async_render_to_info(
- track_template_.variables
- )
- info_changed = True
-
- try:
- result: Union[str, TemplateError] = self._info[template].result()
- except TemplateError as ex:
- result = ex
-
- last_result = self._last_result.get(template)
-
- # Check to see if the result has changed
- if result == last_result:
- continue
-
- if isinstance(result, TemplateError) and isinstance(
- last_result, TemplateError
- ):
+ update = self._render_template_if_ready(track_template_, now, event)
+ if not update:
continue
- updates.append(TrackTemplateResult(template, last_result, result))
+ info_changed = True
+ if isinstance(update, TrackTemplateResult):
+ updates.append(update)
if info_changed:
assert self._track_state_changes
@@ -1348,3 +1359,20 @@ def _render_infos_to_track_states(render_infos: Iterable[RenderInfo]) -> TrackSt
return TrackStates(True, set(), set())
return TrackStates(False, *_entities_domains_from_render_infos(render_infos))
+
+
+@callback
+def _event_triggers_rerender(event: Event, info: RenderInfo) -> bool:
+ """Determine if a template should be re-rendered from an event."""
+ entity_id = event.data.get(ATTR_ENTITY_ID)
+
+ if info.filter(entity_id):
+ return True
+
+ if (
+ event.data.get("new_state") is not None
+ and event.data.get("old_state") is not None
+ ):
+ return False
+
+ return bool(info.filter_lifecycle(entity_id))
--
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