Merge branch 'randomdelay' into 'master'

Spread esi tasks over 10 minutes

See merge request allianceauth/allianceauth!1666

allianceauth/eveonline/tasks.py

@@ -1,4 +1,5 @@
 import logging
+from random import randint
 
 from celery import shared_task
 
@@ -9,7 +10,8 @@ from . import providers
 logger = logging.getLogger(__name__)
 
 TASK_PRIORITY = 7
-CHUNK_SIZE = 500
+CHARACTER_AFFILIATION_CHUNK_SIZE = 500
+EVEONLINE_TASK_JITTER = 600
 
 
 def chunks(lst, n):
@@ -19,13 +21,13 @@ def chunks(lst, n):
 
 
 @shared_task
-def update_corp(corp_id):
+def update_corp(corp_id: int) -> None:
     """Update given corporation from ESI"""
     EveCorporationInfo.objects.update_corporation(corp_id)
 
 
 @shared_task
-def update_alliance(alliance_id):
+def update_alliance(alliance_id: int) -> None:
     """Update given alliance from ESI"""
     EveAllianceInfo.objects.update_alliance(alliance_id).populate_alliance()
 
@@ -37,23 +39,30 @@ def update_character(character_id: int) -> None:
 
 
 @shared_task
-def run_model_update():
+def run_model_update() -> None:
     """Update all alliances, corporations and characters from ESI"""
 
-    #update existing corp models
+    # Queue update tasks for Known Corporation Models
     for corp in EveCorporationInfo.objects.all().values('corporation_id'):
-        update_corp.apply_async(args=[corp['corporation_id']], priority=TASK_PRIORITY)
+        update_corp.apply_async(
+            args=[corp['corporation_id']],
+            priority=TASK_PRIORITY,
+            countdown=randint(1, EVEONLINE_TASK_JITTER))
 
-    # update existing alliance models
+    # Queue update tasks for Known Alliance Models
     for alliance in EveAllianceInfo.objects.all().values('alliance_id'):
-        update_alliance.apply_async(args=[alliance['alliance_id']], priority=TASK_PRIORITY)
+        update_alliance.apply_async(
+            args=[alliance['alliance_id']],
+            priority=TASK_PRIORITY,
+            countdown=randint(1, EVEONLINE_TASK_JITTER))
 
-    # update existing character models
+    # Queue update tasks for Known Character Models
     character_ids = EveCharacter.objects.all().values_list('character_id', flat=True)
-    for character_ids_chunk in chunks(character_ids, CHUNK_SIZE):
+    for character_ids_chunk in chunks(character_ids, CHARACTER_AFFILIATION_CHUNK_SIZE):
         update_character_chunk.apply_async(
-            args=[character_ids_chunk], priority=TASK_PRIORITY
+            args=[character_ids_chunk],
-        )
+            priority=TASK_PRIORITY,
+            countdown=randint(1, EVEONLINE_TASK_JITTER))
 
 
 @shared_task
@@ -68,8 +77,9 @@ def update_character_chunk(character_ids_chunk: list):
         logger.info("Failed to bulk update characters. Attempting single updates")
         for character_id in character_ids_chunk:
             update_character.apply_async(
-                args=[character_id], priority=TASK_PRIORITY
+                args=[character_id],
-            )
+                priority=TASK_PRIORITY,
+                countdown=randint(1, EVEONLINE_TASK_JITTER))
         return
 
     affiliations = {
@@ -107,5 +117,5 @@ def update_character_chunk(character_ids_chunk: list):
 
             if corp_changed or alliance_changed or name_changed:
                 update_character.apply_async(
-                    args=[character.get('character_id')], priority=TASK_PRIORITY
+                    args=[character.get('character_id')],
-                )
+                    priority=TASK_PRIORITY)

allianceauth/eveonline/tests/test_tasks.py

@@ -84,7 +84,7 @@ class TestUpdateTasks(TestCase):
 @override_settings(CELERY_ALWAYS_EAGER=True)
 @patch('allianceauth.eveonline.providers.esi_client_factory')
 @patch('allianceauth.eveonline.tasks.providers')
-@patch('allianceauth.eveonline.tasks.CHUNK_SIZE', 2)
+@patch('allianceauth.eveonline.tasks.CHARACTER_AFFILIATION_CHUNK_SIZE', 2)
 class TestRunModelUpdate(TransactionTestCase):
     def test_should_run_updates(self, mock_providers, mock_esi_client_factory):
         # given
@@ -139,7 +139,7 @@ class TestRunModelUpdate(TransactionTestCase):
 @patch('allianceauth.eveonline.tasks.update_character', wraps=update_character)
 @patch('allianceauth.eveonline.providers.esi_client_factory')
 @patch('allianceauth.eveonline.tasks.providers')
-@patch('allianceauth.eveonline.tasks.CHUNK_SIZE', 2)
+@patch('allianceauth.eveonline.tasks.CHARACTER_AFFILIATION_CHUNK_SIZE', 2)
 class TestUpdateCharacterChunk(TestCase):
     @staticmethod
     def _updated_character_ids(spy_update_character) -> set:

docs/development/tech_docu/celery.md

@@ -168,6 +168,49 @@ example.apply_async(priority=3)
 For defining a priority to tasks, you cannot use the convenient shortcut ``delay()``, but instead need to start a task with ``apply_async()``, which also requires you to pass parameters to your task function differently. Please check out the `official docs <https://docs.celeryproject.org/en/stable/reference/celery.app.task.html#celery.app.task.Task.apply_async>`_ for details.
 :::
 
+## Rate-Limiting and Smoothing of Task Execution
+
+Large numbers of installs running the same crontab (ie. `0 * * * *`) can all slam an external service at the same time.
+
+Consider Artificially smoothing out your tasks with a few methods
+
+### Offset Crontabs
+
+Avoid running your tasks on the hour or other nice neat human numbers, consider 23 minutes on the hour instead of at zero (`28 * * * *`)
+
+### Subset Tasks
+
+Slice your tasks needed up into more manageable chunks and run them more often. 1/10th of your tasks run 10x more often will return the same end result with less peak loads on external services and your task queue.
+
+### Celery ETA/Countdown
+
+Scatter your tasks across a larger window using <https://docs.celeryq.dev/en/latest/userguide/calling.html#eta-and-countdown>
+
+This example will queue up tasks across the next 10 minutes, trickling them into your workers (and the external service)
+
+```python
+for corp in EveCorporationInfo.objects.all().values('corporation_id'):
+    update_corp.apply_async(args=[corp['corporation_id']], priority=TASK_PRIORITY)
+    update_corp.apply_async(
+        args=[corp['corporation_id']],
+        priority=TASK_PRIORITY,
+        countdown=randint(1, 600))
+```
+
+### Celery Rate Limits
+
+Celery Rate Limits come with a small catch, its _per worker_, you may have to be either very conservative or have these configurable by the end user if they varied their worker count.
+
+<https://docs.celeryq.dev/en/latest/userguide/tasks.html#Task.rate_limit>
+
+This example of 10 Tasks per Minute will result in ~100 tasks per minute at 10 Workers
+
+```python
+@shared_task(rate_limit="10/m")
+def update_charactercorporationhistory(character_id: int) -> None:
+    """Update CharacterCorporationHistory models from ESI"""
+```
+
 ## What special features should I be aware of?
 
 Every Alliance Auth installation will come with a couple of special celery related features "out-of-the-box" that you can make use of in your apps.
@@ -192,6 +235,6 @@ You can use it like so:
 
 Please see the [official documentation](https://pypi.org/project/celery_once/) of celery-once for details.
 
-### task priorities
+### Task Priorities
 
 Alliance Auth is using task priorities to enable priority-based scheduling of task execution. Please see [How can I use priorities for tasks?](#how-can-i-use-priorities-for-tasks) for details.