Use secrete key to make IMAP polling offset stable

src/paperless/settings/custom.py

@@ -1,7 +1,7 @@
 import datetime
 import logging
 import os
-import random
+from hashlib import sha256
 from pathlib import Path
 from typing import Any
 
@@ -178,7 +178,8 @@ def parse_beat_schedule() -> dict:
             and task["env_key"] not in os.environ
         ):
             # Spread default polling across the ten-minute interval.
-            offset = random.randrange(10)
+            secret = os.environ["PAPERLESS_SECRET_KEY"].encode()
+            offset = int.from_bytes(sha256(secret).digest()) % 10
             minutes = ",".join(str(minute) for minute in range(offset, 60, 10))
             value = f"{minutes} * * * *"
         # I find https://crontab.guru/ super helpful

src/paperless/tests/settings/test_custom_parsers.py

@@ -168,7 +168,7 @@ class TestParseHostingSettings:
 def make_expected_schedule(
     overrides: dict[str, dict[str, Any]] | None = None,
     disabled: set[str] | None = None,
-    email_minute: str = "3,13,23,33,43,53",
+    email_minute: str = "6,16,26,36,46,56",
 ) -> dict[str, Any]:
     """
     Build the expected schedule with optional overrides and disabled tasks.
@@ -310,8 +310,11 @@ class TestParseBeatSchedule:
         expected: dict[str, Any],
         mocker: MockerFixture,
     ) -> None:
-        mocker.patch.dict(os.environ, env, clear=False)
-        mocker.patch("paperless.settings.custom.random.randrange", return_value=3)
+        mocker.patch.dict(
+            os.environ,
+            {"PAPERLESS_SECRET_KEY": "test-secret", **env},
+            clear=False,
+        )
         schedule = parse_beat_schedule()
         assert schedule == expected