Creating cogs/extensions

Cogs are analogous to modules that extend the core of the bot - thus adding to its functions and abilities. They also allow you to break down and organize your bot's collection of commands/listeners (which is useful when your bot's command list becomes quite extensive).

note

Cogs are typically used alongside with Extensions. You can read more about them in the documentation.

Creating files

What we code here will extend on the code from Initial Files, and thus we assume that there already exists a main.py file in your directory which initiates a commands.Bot() instance.

main.py

import disnake
from disnake.ext import commands

bot = commands.Bot()


@bot.event
async def on_ready():
    print("The bot is ready!")


bot.run("YOUR_BOT_TOKEN")

Next, we will create a new Python file either in the same directory as main.py or in a subfolder (which is recommended). For the sake of being organized, we will create the cog file in a separate cogs folder, and name the file ping.py just for the "ping" command. If you're strictly following the guide, your file directory should look something like this:

.
├── cogs/
│   └── ping.py
├── main.py
└── secrets.env

Initial code

Inheriting a class

The first step is to create a class in ping.py that inherits from the commands.Cog, along with a constructor that takes in the bot object as its only argument and saves it. This is where we will be putting in our commands.

ping.py

from disnake.ext import commands


class PingCommand(commands.Cog):
    """This will be for a ping command."""

    def __init__(self, bot: commands.Bot):
        self.bot = bot

tip

We typehint bot: commands.Bot here to give the IDE an idea of what the argument type is. It is not necessary, but can be useful in development when adding certain arguments to your commands.

Registering commands

Now, to define a slash command inside the class, we will use the commands.slash_command() decorator. It functions the same as bot.slash_command(), but works in cogs as well.

ping.py

import disnake
from disnake.ext import commands


class PingCommand(commands.Cog):
    """This will be for a ping command."""

    def __init__(self, bot: commands.Bot):
        self.bot = bot

    @commands.slash_command()
    async def ping(self, inter: disnake.ApplicationCommandInteraction):
        """Get the bot's current websocket latency."""
        await inter.response.send_message(f"Pong! {round(self.bot.latency * 1000)}ms")

Note that we're using self as the first argument, since the command function is inside a class.

Adding setup function

The last thing that needs to be added to this file is a setup function, so that disnake can load the cog when it is added to main.py.

ping.py

import disnake
from disnake.ext import commands


class PingCommand(commands.Cog):
    """This will be for a ping command."""

    def __init__(self, bot: commands.Bot):
        self.bot = bot

    @commands.slash_command()
    async def ping(self, inter: disnake.ApplicationCommandInteraction):
        """Get the bot's current websocket latency."""
        await inter.response.send_message(f"Pong! {round(self.bot.latency * 1000)}ms")


def setup(bot: commands.Bot):
    bot.add_cog(PingCommand(bot))

This cog file can now be added to the bot via the bot.load_extension() method in main.py.

main.py

import disnake
from disnake.ext import commands

bot = commands.Bot()


@bot.event
async def on_ready():
    print("The bot is ready!")


bot.load_extension("cogs.ping")  # Note: We did not append the .py extension.

bot.run("YOUR_BOT_TOKEN")

Note that we've input "cogs.ping" here, since the ping.py file is inside the cogs folder. Therefore, the basic syntax for loading an extension is bot.load_extension("<folder_name>.<file_name>").

And that concludes the use of cogs with disnake! You can now create multiple cogs to group and organize your commands/events, and load/unload them via your main file. More information on special cog methods and meta options can be found in the documentation.

Syntax changes

Cogs represent a fairly drastic change in the way you write commands and bots, so here's a list you can come back to for the primary syntax used in cogs:

• Each cog is a Python class that subclasses commands.Cog.
• Decorators for commands in cogs:
  • Command - commands.command()
  • Slash command - commands.slash_command()
  • User command - commands.user_command()
  • Message command - commands.message_command()
• Every listener is marked with the commands.Cog.listener() decorator.
• Cogs are then registered with the Bot.add_cog call, and are subsequently removed with the Bot.remove_cog call.

^{Source: Disnake Documentation}

Cogs represent a fairly drastic change in the way you write commands and bots. Thus, it is recommended that you get familiar with this syntax - since the code we use in this section is largely tailored for cogs.