Merge pull request #1367 from python-discord/bug/backend/bot-4x/chunk-sync-requests

Sync: chunk user requests

2 files changed, 26 insertions, 13 deletions

diff --git a/bot/exts/backend/sync/_syncers.py b/bot/exts/backend/sync/_syncers.py
index 2eb9f9971..c9f2d2da8 100644
--- a/bot/exts/backend/sync/_syncers.py
+++ b/bot/exts/backend/sync/_syncers.py
@@ -5,12 +5,15 @@ from collections import namedtuple
 
 from discord import Guild
 from discord.ext.commands import Context
+from more_itertools import chunked
 
 import bot
 from bot.api import ResponseCodeError
 
 log = logging.getLogger(__name__)
 
+CHUNK_SIZE = 1000
+
 # These objects are declared as namedtuples because tuples are hashable,
 # something that we make use of when diffing site roles against guild roles.
 _Role = namedtuple('Role', ('id', 'name', 'colour', 'permissions', 'position'))
@@ -207,10 +210,13 @@ class UserSyncer(Syncer):
     @staticmethod
     async def _sync(diff: _Diff) -> None:
         """Synchronise the database with the user cache of `guild`."""
+        # Using asyncio.gather would still consume too many resources on the site.
         log.trace("Syncing created users...")
         if diff.created:
-            await bot.instance.api_client.post("bot/users", json=diff.created)
+            for chunk in chunked(diff.created, CHUNK_SIZE):
+                await bot.instance.api_client.post("bot/users", json=chunk)
 
         log.trace("Syncing updated users...")
         if diff.updated:
-            await bot.instance.api_client.patch("bot/users/bulk_patch", json=diff.updated)
+            for chunk in chunked(diff.updated, CHUNK_SIZE):
+                await bot.instance.api_client.patch("bot/users/bulk_patch", json=chunk)
diff --git a/tests/bot/exts/backend/sync/test_users.py b/tests/bot/exts/backend/sync/test_users.py
index 61673e1bb..27932be95 100644
--- a/tests/bot/exts/backend/sync/test_users.py
+++ b/tests/bot/exts/backend/sync/test_users.py
@@ -188,30 +188,37 @@ class UserSyncerSyncTests(unittest.IsolatedAsyncioTestCase):
     """Tests for the API requests that sync users."""
 
     def setUp(self):
-        patcher = mock.patch("bot.instance", new=helpers.MockBot())
-        self.bot = patcher.start()
-        self.addCleanup(patcher.stop)
+        bot_patcher = mock.patch("bot.instance", new=helpers.MockBot())
+        self.bot = bot_patcher.start()
+        self.addCleanup(bot_patcher.stop)
+
+        chunk_patcher = mock.patch("bot.exts.backend.sync._syncers.CHUNK_SIZE", 2)
+        self.chunk_size = chunk_patcher.start()
+        self.addCleanup(chunk_patcher.stop)
+
+        self.chunk_count = 2
+        self.users = [fake_user(id=i) for i in range(self.chunk_size * self.chunk_count)]
 
     async def test_sync_created_users(self):
         """Only POST requests should be made with the correct payload."""
-        users = [fake_user(id=111), fake_user(id=222)]
-
-        diff = _Diff(users, [], None)
+        diff = _Diff(self.users, [], None)
         await UserSyncer._sync(diff)
 
-        self.bot.api_client.post.assert_called_once_with("bot/users", json=diff.created)
+        self.bot.api_client.post.assert_any_call("bot/users", json=diff.created[:self.chunk_size])
+        self.bot.api_client.post.assert_any_call("bot/users", json=diff.created[self.chunk_size:])
+        self.assertEqual(self.bot.api_client.post.call_count, self.chunk_count)
 
         self.bot.api_client.put.assert_not_called()
         self.bot.api_client.delete.assert_not_called()
 
     async def test_sync_updated_users(self):
         """Only PUT requests should be made with the correct payload."""
-        users = [fake_user(id=111), fake_user(id=222)]
-
-        diff = _Diff([], users, None)
+        diff = _Diff([], self.users, None)
         await UserSyncer._sync(diff)
 
-        self.bot.api_client.patch.assert_called_once_with("bot/users/bulk_patch", json=diff.updated)
+        self.bot.api_client.patch.assert_any_call("bot/users/bulk_patch", json=diff.updated[:self.chunk_size])
+        self.bot.api_client.patch.assert_any_call("bot/users/bulk_patch", json=diff.updated[self.chunk_size:])
+        self.assertEqual(self.bot.api_client.patch.call_count, self.chunk_count)
 
         self.bot.api_client.post.assert_not_called()
         self.bot.api_client.delete.assert_not_called()