Cache transient templates compiles provided via api (#89065)

* Cache transient templates compiles provided via api

partially fixes #89047 (there is more going on here)

* add a bit more coverage just to be sure

* switch method

* Revert "switch method"

This reverts commit 0e9e1c8cbe8753159f4fd6775cdc9cf217d66f0e.

* tweak

* hold hass

* empty for github flakey

homeassistant/components/api/__init__.py

@@ -1,5 +1,6 @@
 """Rest API for Home Assistant."""
 import asyncio
+from functools import lru_cache
 from http import HTTPStatus
 import logging
 
@@ -350,6 +351,12 @@ class APIComponentsView(HomeAssistantView):
         return self.json(request.app["hass"].config.components)
 
 
+@lru_cache
+def _cached_template(template_str: str, hass: ha.HomeAssistant) -> template.Template:
+    """Return a cached template."""
+    return template.Template(template_str, hass)
+
+
 class APITemplateView(HomeAssistantView):
     """View to handle Template requests."""
 
@@ -362,7 +369,7 @@ class APITemplateView(HomeAssistantView):
             raise Unauthorized()
         try:
             data = await request.json()
-            tpl = template.Template(data["template"], request.app["hass"])
+            tpl = _cached_template(data["template"], request.app["hass"])
             return tpl.async_render(variables=data.get("variables"), parse_result=False)
         except (ValueError, TemplateError) as ex:
             return self.json_message(

homeassistant/components/mobile_app/webhook.py

@@ -4,7 +4,7 @@ from __future__ import annotations
 import asyncio
 from collections.abc import Callable, Coroutine
 from contextlib import suppress
-from functools import wraps
+from functools import lru_cache, wraps
 from http import HTTPStatus
 import logging
 import secrets
@@ -365,6 +365,12 @@ async def webhook_stream_camera(
     return webhook_response(resp, registration=config_entry.data)
 
 
+@lru_cache
+def _cached_template(template_str: str, hass: HomeAssistant) -> template.Template:
+    """Return a cached template."""
+    return template.Template(template_str, hass)
+
+
 @WEBHOOK_COMMANDS.register("render_template")
 @validate_schema(
     {
@@ -381,7 +387,7 @@ async def webhook_render_template(
     resp = {}
     for key, item in data.items():
         try:
-            tpl = template.Template(item[ATTR_TEMPLATE], hass)
+            tpl = _cached_template(item[ATTR_TEMPLATE], hass)
             resp[key] = tpl.async_render(item.get(ATTR_TEMPLATE_VARIABLES))
         except TemplateError as ex:
             resp[key] = {"error": str(ex)}

homeassistant/components/websocket_api/commands.py

@@ -4,6 +4,7 @@ from __future__ import annotations
 from collections.abc import Callable
 from contextlib import suppress
 import datetime as dt
+from functools import lru_cache
 import json
 from typing import Any, cast
 
@@ -424,6 +425,12 @@ def handle_ping(
     connection.send_message(pong_message(msg["id"]))
 
 
+@lru_cache
+def _cached_template(template_str: str, hass: HomeAssistant) -> template.Template:
+    """Return a cached template."""
+    return template.Template(template_str, hass)
+
+
 @decorators.websocket_command(
     {
         vol.Required("type"): "render_template",
@@ -440,7 +447,7 @@ async def handle_render_template(
 ) -> None:
     """Handle render_template command."""
     template_str = msg["template"]
-    template_obj = template.Template(template_str, hass)
+    template_obj = _cached_template(template_str, hass)
     variables = msg.get("variables")
     timeout = msg.get("timeout")
     info = None

tests/components/api/test_init.py

@@ -349,6 +349,52 @@ async def test_api_template(hass: HomeAssistant, mock_api_client: TestClient) ->
 
     assert body == "10"
 
+    hass.states.async_set("sensor.temperature", 20)
+    resp = await mock_api_client.post(
+        const.URL_API_TEMPLATE,
+        json={"template": "{{ states.sensor.temperature.state }}"},
+    )
+
+    body = await resp.text()
+
+    assert body == "20"
+
+    hass.states.async_remove("sensor.temperature")
+    resp = await mock_api_client.post(
+        const.URL_API_TEMPLATE,
+        json={"template": "{{ states.sensor.temperature.state }}"},
+    )
+
+    body = await resp.text()
+
+    assert body == ""
+
+
+async def test_api_template_cached(
+    hass: HomeAssistant, mock_api_client: TestClient
+) -> None:
+    """Test the template API uses the cache."""
+    hass.states.async_set("sensor.temperature", 30)
+
+    resp = await mock_api_client.post(
+        const.URL_API_TEMPLATE,
+        json={"template": "{{ states.sensor.temperature.state }}"},
+    )
+
+    body = await resp.text()
+
+    assert body == "30"
+
+    hass.states.async_set("sensor.temperature", 40)
+    resp = await mock_api_client.post(
+        const.URL_API_TEMPLATE,
+        json={"template": "{{ states.sensor.temperature.state }}"},
+    )
+
+    body = await resp.text()
+
+    assert body == "40"
+
 
 async def test_api_template_error(
     hass: HomeAssistant, mock_api_client: TestClient