Introduction to Click Plugins

Click-plugins is an extension for the Click library which enables adding plugins to Click applications. It’s an easy way to modularize code and make command-line tools extensible.

Getting Started

First, you need to install the click-plugins package:

  $ pip install click-plugins

Creating a Click Command

Here’s a basic example of setting up a Click command:

  import click
  
  @click.command()
  @click.argument('name')
  def hello(name):
      click.echo(f"Hello, {name}!")

  if __name__ == "__main__":
      hello()

Setting Up Plugins

Let’s move on to creating a plugin system:

  import click
  import click_plugins

  @click_plugins.with_plugins(ep_name='myapp.plugins')
  @click.group()
  def cli():
      pass

  if __name__ == "__main__":
      cli()

Creating a Plugin

Now, let’s create a plugin for our Click application:

  import click
  
  @click.command()
  @click.argument('path')
  def readfile(path):
      """Read and display a file"""
      with open(path, 'r') as f:
          click.echo(f.read())

  plugin = readfile

We would save this plugin in a package that could be dynamically loaded.

Registering Plugins

To dynamically register plugins, specify entry points in your setup.py file:

  from setuptools import setup

  setup(
      name="myapp",
      version="0.1",
      packages=["myapp"],
      entry_points="""
      [myapp.plugins]
      readfile=myapp.plugins:readfile
      """
  )

Example Application

Now let’s bring it all together in an example application:

  # myapp/main.py
  import click
  import click_plugins
  
  @click_plugins.with_plugins(ep_name='myapp.plugins')
  @click.group()
  def cli():
      pass

  if __name__ == "__main__":
      cli()

  # myapp/plugins.py
  import click
  
  @click.command()
  @click.argument('path')
  def readfile(path):
      """Read and display a file"""
      with open(path, 'r') as f:
          click.echo(f.read())

  plugin = readfile

Running the Application

To run the application, navigate to the project directory and execute:

  $ myapp readfile example.txt

With this approach, you can dynamically add new commands simply by creating new plugins without modifying the core application.

Hash: 7ebc4bf3469f536d9fc483d35d493057231ec3f7a64d011d0a956cf03ee2dbb6