#!/usr/bin/env python

import sys
import time
import subprocess

try:
    sub_command = sys.argv[1:-1]
    bytes_per_chunk = int(sys.argv[-1])
except:
    print '''pull1
    
usage: pull1 sub_command_and_args... bytes_per_chunk

Runs sub_command_and_args in a subprocess, reads bytes_per_chunk from the
subprocess, prints length read and 1 second timestamps.'''
    sys.exit(1)

prog = sys.argv[0].split('/')[-1] + ':'

proc = subprocess.Popen(sub_command, stdout=subprocess.PIPE, close_fds=True)
print prog, 'pid', proc.pid

start_time = time.time()
sum = 0
secs = 1
while True:
    chunk = proc.stdout.read(bytes_per_chunk)
    if not chunk: break
    print prog, 'chunk size', len(chunk)
    sum += len(chunk)
    if time.time() - start_time >= secs:
        print prog, 'elapsed', secs, ' average bytes-per-sec', sum // secs
        secs += 1
    sys.stdout.flush()