slack_button.py

from gpiozero import Button
from signal import pause
import sys, requests, json

pressed_count = 0
webhook_url = 'YOUR-WEBHOOK'
message = 'Hello, world!'

# action to perform on press
def DoAction():
    global message
    SendMessage(message)


# send a message to the webhook
def SendMessage(message):
    payload = {'text': message}
    r = requests.post(webhook_url, data=json.dumps(payload))
    print(r.text)


# run the things
def main(argv):
    global message
    
    if argv == '--help' or argv == 'help':
        print('Type: "> slack_button.py <your_message_here>"')
        return
    
    # set message to argument
    message = argv
    print('Using message: {}'.format(message))
    
    # create button and bind to GPIO#4
    button = Button(4)
    button.when_pressed = DoAction

    print('Waiting for input...')
    pause()


if __name__ == '__main__':
    if len(sys.argv) > 1:
        main(sys.argv[1])
    else:
        print('No message set, defaulting to "Hello, world!"')
        main(message)