retry and report Frigate+ connection failures at startup (#24545)

A Frigate+ model that wasn't cached yet needed api.frigate.video at startup, and when it couldn't be reached (a network that comes up late, a DNS blip) the requests ConnectionError wasn't a validation error, so Frigate crashed with a traceback before it could start. PlusApi requests now go through a session that retries connection failures for about 30 seconds, and a connection failure that outlasts that is raised as a ValueError so it shows up as a clear config validation error instead.

frigate/plus.py

@@ -9,7 +9,9 @@ from typing import Any
 import cv2
 import requests
 from numpy import ndarray
+from requests.adapters import HTTPAdapter
 from requests.models import Response
+from urllib3.util.retry import Retry
 
 from frigate.const import MODEL_CACHE_DIR, PLUS_API_HOST, PLUS_ENV_VAR
 
@@ -101,6 +103,13 @@ class PlusApi:
         self._is_active: bool = self.key is not None
         self._token_data: dict = {}
 
+        # Retry connection failures so a network that comes up late at startup
+        # doesn't fail the Frigate+ model download
+        self._session = requests.Session()
+        self._session.mount(
+            self.host, HTTPAdapter(max_retries=Retry(connect=5, backoff_factor=1))
+        )
+
     def _refresh_token_if_needed(self) -> None:
         if (
             self._token_data.get("expires") is None
@@ -111,7 +120,9 @@ class PlusApi:
                     "Plus API key not set. See https://docs.frigate.video/integrations/plus#set-your-api-key"
                 )
             parts = self.key.split(":")
-            r = requests.get(f"{self.host}/v1/auth/token", auth=(parts[0], parts[1]))
+            r = self._session.get(
+                f"{self.host}/v1/auth/token", auth=(parts[0], parts[1])
+            )
             if not r.ok:
                 raise Exception(f"Unable to refresh API token: {r.text}")
             self._token_data = r.json()
@@ -121,19 +132,19 @@ class PlusApi:
         return {"authorization": f"Bearer {self._token_data.get('accessToken')}"}
 
     def _get(self, path: str) -> Response:
-        return requests.get(
+        return self._session.get(
             f"{self.host}/v1/{path}", headers=self._get_authorization_header()
         )
 
     def _post(self, path: str, data: dict) -> Response:
-        return requests.post(
+        return self._session.post(
             f"{self.host}/v1/{path}",
             headers=self._get_authorization_header(),
             json=data,
         )
 
     def _put(self, path: str, data: dict) -> Response:
-        return requests.put(
+        return self._session.put(
             f"{self.host}/v1/{path}",
             headers=self._get_authorization_header(),
             json=data,