write_random.py

#!/usr/bin/env python

import os
import time
import whisper
import sys
from optparse import OptionParser
from random import Random

SPARSE_SPACING = 5

option_parser = OptionParser(
    usage='''%prog [options] <file>

%prog writes random points to a whisper file for testing purposes''')

option_parser.add_option(
    '--from', default=None, dest='_from',
    type='string', help='Begin writing points at this time')
option_parser.add_option(
    '--until', default=None,
    type='string', help='Write points until this time')
option_parser.add_option(
    '--sparse', default=False,
    action='store_true', help='Write sparsely (resulting in None values)')
option_parser.add_option(
    '--mean', default=100,
    type='float', help='Mean of generated values (default: 100)')
option_parser.add_option(
    '--deviation', default=50,
    type='float', help='Standard deviation of generated values (default: 50)')
option_parser.add_option(
    '--integers', default=False,
    action='store_true', help='Use only integers as values')

(options, args) = option_parser.parse_args()

if len(args) < 1:
  option_parser.print_usage()
  sys.exit(1)

path = args[0]

if not os.path.exists(path):
  sys.stderr.write("[ERROR] File '%s' does not exist!\n\n" % path)
  option_parser.print_usage()
  sys.exit(1)

def generate_points(from_time, until_time, step):
  rand = Random()

  for ts in xrange(from_time, until_time, step):
    new_value = rand.normalvariate(options.mean, options.deviation)
    if options.integers:
      new_value = int(new_value)
    if options.sparse:
      new_value = rand.choice( [new_value] * (SPARSE_SPACING - 1) + [None] )
    if new_value is not None:
      yield (ts, new_value)

file_info = whisper.info(path)
now = int(time.time())

from_time = now - file_info['maxRetention']
until_time = now
if options._from is not None:
  if options._from > from_time:
    from_time = options._from
if options.until is not None:
  if options.until < now:
    until_time = options.until

whisper.update_many(path, generate_points(from_time, until_time, file_info['archives'][0]['secondsPerPoint']))