How to read realtime microphone audio volume in python and ffmpeg or similar

Thanks to @Matthias for the suggestion to use the sounddevice module. It's exactly what I need.

For posterity, here is a working example that prints real-time audio levels to the shell:

# Print out realtime audio volume as ascii bars

import sounddevice as sd
import numpy as np

def print_sound(indata, outdata, frames, time, status):
    volume_norm = np.linalg.norm(indata)*10
    print ("|" * int(volume_norm))

with sd.Stream(callback=print_sound):
    sd.sleep(10000)

Python 3 user here
I had few problems to make that work so I used: https://python-sounddevice.readthedocs.io/en/0.3.3/examples.html#plot-microphone-signal-s-in-real-time
And I need to install sudo apt-get install python3-tk for python 3.6 look Tkinter module not found on Ubuntu
Then I modified script:

#!/usr/bin/env python3
import numpy as np
import sounddevice as sd

duration = 10 #in seconds

def audio_callback(indata, frames, time, status):
   volume_norm = np.linalg.norm(indata) * 10
   print("|" * int(volume_norm))


stream = sd.InputStream(callback=audio_callback)
with stream:
   sd.sleep(duration * 1000)

And yes it working :)