Prototype of a 'dynamic' prompt showing CPU load over 10 seconds as a sparkline.

dynamic_cpu_load.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""
Prototype of a 'dynamic' prompt showing CPU load over 10 seconds as a sparkline.

Requires ``psutil``...

Not finished...
"""

import time

from prompt_toolkit.application import Application
from prompt_toolkit.interface import CommandLineInterface
from prompt_toolkit.layout import Window
from prompt_toolkit.layout.controls import BufferControl
from prompt_toolkit.layout.processors import BeforeInput
from prompt_toolkit.shortcuts import create_eventloop
from prompt_toolkit.token import Token
from psutil import cpu_percent

from sparklines import sparklines


CPU_LOAD_HISTORY = []


def _clock_tokens(cli):
    "Tokens to be shown before the prompt."
    
    CPU_LOAD_HISTORY.append(cpu_percent())    
    sparkline = sparklines(CPU_LOAD_HISTORY[-10:])[0] + " (CPU)"
    return [
        (Token.Prompt, sparkline),
        (Token.Prompt, ' - Enter something: ')
    ]


def main():
    eventloop = create_eventloop()
    done = [False]  # Non local

    def on_read_start(cli):
        """
        This function is called when we start reading at the input.
        (Actually, the start of the read-input event loop.)
        """
        # The following function should be run in the background.
        # We do it by using an executor thread from the `CommandLineInterface`
        # instance.
        def run():
            # Send every second a redraw request.
            while not done[0]:
                time.sleep(1)
                cli.request_redraw()

        cli.eventloop.run_in_executor(run)

    def on_read_stop(cli):
        done[0] = True

    app = Application(
        layout=Window(BufferControl(input_processors=[BeforeInput(_clock_tokens)])),
        on_start=on_read_start,
        on_stop=on_read_stop)

    cli = CommandLineInterface(application=app, eventloop=eventloop)

    code_obj = cli.run()
    print('You said: %s' % code_obj.text)

    eventloop.close()


if __name__ == '__main__':
    main()