clidesc 0.3.0

An automatic CLI interface framework.

clidesc

clidesc is a CLI interface framework that can be used to build simple, yet functional, command line interfaces with minimal client code.

The goal is to create a framework to build the command line interface only using configuration files (YAML or JSON format), and minimizing the need to write code for it.

Usage

To create a simple "Greeting" application, the CLI definition file, should look like:

---
program: greeting
description: A greeting application.
version: 1.0
handler: greeting.hello
arguments:
  - name: someone
    description: Someone to greet.
    type: string
    required: true

And the application code would be:

# Contents of greeting.py

from clidesc import CLIDesc

def hello(someone):
    print(f"Hello, {someone}!")

if __name__ == "__main__":
    cli = CLIDesc.from_file("greeting.yml")
    cli.run()

With this configuration, the application will have options to display its version (--version), help instructions (-h or --help), and a required positional argument. If run with --help, the output is:

usage: greeting [-h] [--version] someone

A greeting application.

positional arguments:
  someone     Someone to greet.

optional arguments:
  -h, --help  show this help message and exit
  --version   display program version

If the application does not receive the required argument, an error is displayed. For example, the output for running greeting is:

usage: greeting [-h] [--version] someone
greeting: error: the following arguments are required: someone

When running an application with one parameter, greeting World, the output would be:

Hello, World!

You may also use clidesc to automatically format the output returned by the handler methods. Use the output attribute along with the handler method to configure the output format.

The next example configures the output format, with a formatting string, that follows Python's formatting rules.

---
program: output
description: Auto-formatting output.
version: 1.0
handler: output.hello
output:
  format: "Hello, {someone}"
arguments:
  - name: someone
    description: Someone to greet.
    required: true

And the code for this application would be:

# contents of output.py.

from clidesc import CLIDesc


def hello(someone):
    """Greet someone."""
    return {"someone": someone}


if __name__ == "__main__":
    cli = CLIDesc.from_file('output.yaml'))
    cli.run()

Applications with multiple commands and command groups (like git) are supported through sub_commands. Each command in sub_command can have its own sub_command, creating a command hierarchy (deep hierarchies are not recommended).

The configuration for such application would be:

---
program: multi
description: A multi-command application.
version: 1.0
sub_commands:
  title: Commands
  description: Application sub-commands
  group_name: Sub commands
  commands:
    - name: abc
      description: First command.
      handler: multi.abc
      arguments:
      - name: some_arg
        description: Some argument.
    - name: xyz
      description: Second command.
      handler: multi.xyz
      arguments:
      - name: another_arg
        description: Another argument.

And the client code:

# contents of multi.py

from clidesc import CLIDesc

def abc(some_arg):
    """Greet someone."""
    print(f"ABC: {some_arg}")


def xyz(another_arg):
    """Greet someone."""
    print(f"XYZ: {another_arg}")


if __name__ == "__main__":
    cli = CLIDesc.from_file("multi.yml")
    cli.run()