Warms up a web server by sending requests until the maximum or average response duration falls below a given threshold

warmup.py

#!/usr/bin/env python3
# also compatible with Python 2.7
# and Python 2.6 (requires argparse)

"""
Warms up a web server by sending requests until the maximum or average response
duration falls below a given threshold. 

"""

# See warmup.py -h for usage.


try:
    from argparse import ArgumentParser
except ImportError:
    import sys
    sys.exit('Please "pip install argparse" if you\'re on Python <2.7')
from collections import deque
import time
try:
    from urllib2 import urlopen         # Python 2.x
except ImportError:
    from urllib.request import urlopen  # Python 3.x
try:
    range = xrange  # Python 2.x
except NameError:
    pass            # Python 3.x


def main(options):
    window = deque()
    window_time = 0.0
    print('reqno duration average maximum window')
    request_no = 0
    while not options.num_requests or request_no < options.num_requests:
        request_no += 1
        start = time.time()
        response = urlopen(options.url[0])
        response.read()
        end = time.time()
        elapsed_ms = 1000 * (end - start)

        window.append(elapsed_ms)
        window_time += elapsed_ms
        if len(window) > options.window_size:
            window_time -= window.popleft()
        window_size = len(window)
        average = window_time / window_size
        longest = max(window)

        print('{request_no:5}'
              ' {elapsed_ms:6.0f}ms'
              ' {average:5.0f}ms'
              ' {longest:5.0f}ms'
              ' {window_size:6}'.format(**locals()))

        if window_size == options.window_size:
            if options.max_cutoff and longest <= options.max_cutoff:
                break
            if options.avg_cutoff and average <= options.avg_cutoff:
                break
    
    
if __name__ == '__main__':
    p = ArgumentParser(description=__doc__)
    p.add_argument('url', nargs=1,
                   help='The URL to test')
    p.add_argument('-n', '--num-requests', type=int, default=100,
                   help='Maximum number or requests. 0=forever, default=100.')
    p.add_argument('-w', '--window-size', type=int, default=10,
                   help='Window size to look at, default=10',
                   metavar='WINSIZE')
    p.add_argument('-m', '--max-cutoff', type=int, default=0,
                   help=('Stop when all last WINSIZE responses are faster than'
                         " this, 0=don't stop (the default)"))
    p.add_argument('-a', '--avg-cutoff', type=int, default=0,
                   help=('Stop when average duration of last WINSIZE requests'
                         " is less than this, 0=don't stop (the default)"))
    opts = p.parse_args()
    main(opts)