Optimise startup time (#2662)

* Defer fetching webhooks for python news until first loop, rather than startup

* Defer fetching webhook for buck pond until first duckify, rather than startup

* Use get_or_fetch channel for getting big brother channel at startup

* Defer fetching peps until first time command is ran

* Don't load extensions in a task

BotBase.load_extentions now creates a task by default, so there's no need for us to do this too.

5 files changed, 29 insertions, 50 deletions

diff --git a/bot/bot.py b/bot/bot.py
index 2321232de..92ecbf130 100644
--- a/bot/bot.py
+++ b/bot/bot.py
@@ -2,7 +2,6 @@ import asyncio
 
 import aiohttp
 from pydis_core import BotBase
-from pydis_core.utils import scheduling
 from sentry_sdk import push_scope
 
 from bot import constants, exts
@@ -45,10 +44,7 @@ class Bot(BotBase):
     async def setup_hook(self) -> None:
         """Default async initialisation method for discord.py."""
         await super().setup_hook()
-
-        # This is not awaited to avoid a deadlock with any cogs that have
-        # wait_until_guild_available in their cog_load method.
-        scheduling.create_task(self.load_extensions(exts))
+        await self.load_extensions(exts)
 
     async def on_error(self, event: str, *args, **kwargs) -> None:
         """Log errors raised in event listeners rather than printing them to stderr."""
diff --git a/bot/exts/fun/duck_pond.py b/bot/exts/fun/duck_pond.py
index 63a455131..2abe72678 100644
--- a/bot/exts/fun/duck_pond.py
+++ b/bot/exts/fun/duck_pond.py
@@ -25,15 +25,6 @@ class DuckPond(Cog):
         self.ducked_messages = []
         self.relay_lock = None
 
-    async def cog_load(self) -> None:
-        """Fetches the webhook object, so we can post to it."""
-        await self.bot.wait_until_guild_available()
-
-        try:
-            self.webhook = await self.bot.fetch_webhook(self.webhook_id)
-        except discord.HTTPException:
-            log.exception(f"Failed to fetch webhook with id `{self.webhook_id}`")
-
     @staticmethod
     def is_staff(member: MemberOrUser) -> bool:
         """Check if a specific member or user is staff."""
@@ -74,6 +65,12 @@ class DuckPond(Cog):
 
     async def relay_message(self, message: Message) -> None:
         """Relays the message's content and attachments to the duck pond channel."""
+        if not self.webhook:
+            await self.bot.wait_until_guild_available()
+            # Fetching this can fail if using an invalid webhook id.
+            # Letting this error bubble up is fine as it will cause an error log and sentry event.
+            self.webhook = await self.bot.fetch_webhook(self.webhook_id)
+
         if message.clean_content:
             await send_webhook(
                 webhook=self.webhook,
diff --git a/bot/exts/info/pep.py b/bot/exts/info/pep.py
index 6f50769d0..5f9a41091 100644
--- a/bot/exts/info/pep.py
+++ b/bot/exts/info/pep.py
@@ -29,12 +29,8 @@ class PythonEnhancementProposals(Cog):
     def __init__(self, bot: Bot):
         self.bot = bot
         self.peps: dict[int, str] = {}
-        # To avoid situations where we don't have last datetime, set this to now.
-        self.last_refreshed_peps: datetime = datetime.now(tz=UTC)
-
-    async def cog_load(self) -> None:
-        """Carry out cog asynchronous initialisation."""
-        await self.refresh_peps_urls()
+        # Ensure peps are refreshed the first time this is checked
+        self.last_refreshed_peps: datetime = datetime.min.replace(tzinfo=UTC)
 
     async def refresh_peps_urls(self) -> None:
         """Refresh PEP URLs listing in every 3 hours."""
diff --git a/bot/exts/info/python_news.py b/bot/exts/info/python_news.py
index 76ebf2731..8507a0fec 100644
--- a/bot/exts/info/python_news.py
+++ b/bot/exts/info/python_news.py
@@ -40,19 +40,30 @@ class PythonNews(Cog):
         self.bot = bot
         self.webhook_names = {}
         self.webhook: discord.Webhook | None = None
+        self.fetch_new_media.start()
 
-    async def cog_load(self) -> None:
-        """Carry out cog asynchronous initialisation."""
-        await self.get_webhook_names()
-        await self.get_webhook_and_channel()
+    async def cog_unload(self) -> None:
+        """Stop news posting tasks on cog unload."""
+        self.fetch_new_media.cancel()
 
-    async def start_tasks(self) -> None:
-        """Start the tasks for fetching new PEPs and mailing list messages."""
-        self.fetch_new_media.start()
+    async def get_webhooks(self) -> None:
+        """Get webhook author names from maillist API."""
+        await self.bot.wait_until_guild_available()
+
+        async with self.bot.http_session.get("https://mail.python.org/archives/api/lists") as resp:
+            lists = await resp.json()
+
+        for mail in lists:
+            if mail["name"].split("@")[0] in constants.PythonNews.mail_lists:
+                self.webhook_names[mail["name"].split("@")[0]] = mail["display_name"]
+        self.webhook = await self.bot.fetch_webhook(constants.PythonNews.webhook)
 
     @loop(minutes=20)
     async def fetch_new_media(self) -> None:
         """Fetch new mailing list messages and then new PEPs."""
+        if not self.webhook:
+            await self.get_webhooks()
+
         await self.post_maillist_news()
         await self.post_pep_news()
 
@@ -72,17 +83,6 @@ class PythonNews(Cog):
 
         await self.bot.api_client.put("bot/bot-settings/news", json=response)
 
-    async def get_webhook_names(self) -> None:
-        """Get webhook author names from maillist API."""
-        await self.bot.wait_until_guild_available()
-
-        async with self.bot.http_session.get("https://mail.python.org/archives/api/lists") as resp:
-            lists = await resp.json()
-
-        for mail in lists:
-            if mail["name"].split("@")[0] in constants.PythonNews.mail_lists:
-                self.webhook_names[mail["name"].split("@")[0]] = mail["display_name"]
-
     @staticmethod
     def escape_markdown(content: str) -> str:
         """Escape the markdown underlines and spoilers that aren't in codeblocks."""
@@ -238,17 +238,6 @@ class PythonNews(Cog):
             email_information = await resp.json()
         return thread_information, email_information
 
-    async def get_webhook_and_channel(self) -> None:
-        """Storage #python-news channel Webhook and `TextChannel` to `News.webhook` and `channel`."""
-        await self.bot.wait_until_guild_available()
-        self.webhook = await self.bot.fetch_webhook(constants.PythonNews.webhook)
-
-        await self.start_tasks()
-
-    async def cog_unload(self) -> None:
-        """Stop news posting tasks on cog unload."""
-        self.fetch_new_media.cancel()
-
 
 async def setup(bot: Bot) -> None:
     """Add `News` cog."""
diff --git a/bot/exts/moderation/watchchannels/_watchchannel.py b/bot/exts/moderation/watchchannels/_watchchannel.py
index c3f823982..5250e64d9 100644
--- a/bot/exts/moderation/watchchannels/_watchchannel.py
+++ b/bot/exts/moderation/watchchannels/_watchchannel.py
@@ -20,6 +20,7 @@ from bot.exts.moderation.modlog import ModLog
 from bot.log import CustomLogger, get_logger
 from bot.pagination import LinePaginator
 from bot.utils import CogABCMeta, messages, time
+from bot.utils.channel import get_or_fetch_channel
 from bot.utils.members import get_or_fetch_member
 
 log = get_logger(__name__)
@@ -97,7 +98,7 @@ class WatchChannel(metaclass=CogABCMeta):
         await self.bot.wait_until_guild_available()
 
         try:
-            self.channel = await self.bot.fetch_channel(self.destination)
+            self.channel = await get_or_fetch_channel(self.destination)
         except HTTPException:
             self.log.exception(f"Failed to retrieve the text channel with id `{self.destination}`")