Tweakhancement: add jitter to IMAP polling schedule

src/paperless/settings/custom.py

@@ -1,6 +1,7 @@
 import datetime
 import logging
 import os
+import random
 from pathlib import Path
 from typing import Any
 
@@ -172,6 +173,14 @@ def parse_beat_schedule() -> dict:
         # Don't add disabled tasks to the schedule
         if value == "disable":
             continue
+        if (
+            task["env_key"] == "PAPERLESS_EMAIL_TASK_CRON"
+            and task["env_key"] not in os.environ
+        ):
+            # Spread default polling across the ten-minute interval.
+            offset = random.randrange(10)
+            minutes = ",".join(str(minute) for minute in range(offset, 60, 10))
+            value = f"{minutes} * * * *"
         # I find https://crontab.guru/ super helpful
         # crontab(5) format
         #   - five time-and-date fields

src/paperless/tests/settings/test_custom_parsers.py

@@ -168,6 +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",
 ) -> dict[str, Any]:
     """
     Build the expected schedule with optional overrides and disabled tasks.
@@ -185,7 +186,7 @@ def make_expected_schedule(
     schedule: dict[str, Any] = {
         "Check all e-mail accounts": {
             "task": "paperless_mail.tasks.process_mail_accounts",
-            "schedule": crontab(minute="*/10"),
+            "schedule": crontab(minute=email_minute),
             "options": {
                 "expires": mail_expire,
                 "headers": {"trigger_source": "scheduled"},
@@ -266,6 +267,11 @@ class TestParseBeatSchedule:
         ("env", "expected"),
         [
             pytest.param({}, make_expected_schedule(), id="defaults"),
+            pytest.param(
+                {"PAPERLESS_EMAIL_TASK_CRON": "*/10 * * * *"},
+                make_expected_schedule(email_minute="*/10"),
+                id="email-explicit-default",
+            ),
             pytest.param(
                 {"PAPERLESS_EMAIL_TASK_CRON": "*/50 * * * mon"},
                 make_expected_schedule(
@@ -305,6 +311,7 @@ class TestParseBeatSchedule:
         mocker: MockerFixture,
     ) -> None:
         mocker.patch.dict(os.environ, env, clear=False)
+        mocker.patch("paperless.settings.custom.random.randrange", return_value=3)
         schedule = parse_beat_schedule()
         assert schedule == expected