Add a simple error handler cog

1 files changed, 42 insertions, 0 deletions

diff --git a/metricity/exts/error_handler.py b/metricity/exts/error_handler.py
new file mode 100644
index 0000000..3d42d05
--- /dev/null
+++ b/metricity/exts/error_handler.py
@@ -0,0 +1,42 @@
+"""Handles errors emitted from commands."""
+
+import discord
+from botcore.utils import logging
+from discord.ext import commands
+
+log = logging.get_logger(__name__)
+
+
+SUPPRESSED_ERRORS = (
+    commands.errors.CommandNotFound,
+    commands.errors.CheckFailure,
+)
+
+
+class ErrorHandler(commands.Cog):
+    """Handles errors emitted from commands."""
+
+    def __init__(self, bot: commands.Bot) -> None:
+        self.bot = bot
+
+    def _get_error_embed(self, title: str, body: str) -> discord.Embed:
+        """Return an embed that contains the exception."""
+        return discord.Embed(
+            title=title,
+            colour=discord.Colour.red(),
+            description=body
+        )
+
+    @commands.Cog.listener()
+    async def on_command_error(self, ctx: commands.Context, e: commands.errors.CommandError) -> None:
+        """Provide generic command error handling."""
+        if any(isinstance(e, suppressed_error) for suppressed_error in SUPPRESSED_ERRORS):
+            log.debug(
+                f"Command {ctx.command} invoked by {ctx.message.author} with error "
+                f"{e.__class__.__name__}: {e}"
+            )
+
+
+async def setup(bot: commands.Bot) -> None:
+    """Load the ErrorHandler cog."""
+    await bot.add_cog(ErrorHandler(bot))