bwmon/aggregator.py

   1 from subprocess import Popen, PIPE
   2 from datetime import datetime
   3 import re
   4 import collections
   5 import shlex
   6
   7 class Aggregator():
   8
   9     def __init__(self, monitors):
  10         self.monitors = monitors
  11         self.line_regex = re.compile('\s*(?P<in>\d+)\s*/\s*(?P<out>\d+)\s*--\s*(?P<proc>.*)')
  12
  13     def launch_monitors(self):
  14
  15         outpipe = PIPE
  16
  17         for m in self.monitors:
  18             args = shlex.split(m)
  19             proc = Popen(args, stdin=PIPE, stdout=outpipe, stderr=PIPE, bufsize=1)
  20
  21             if outpipe == PIPE:
  22                 outpipe = proc.stdout
  23
  24         return outpipe
  25
  26
  27     def run(self):
  28
  29         outpipe = self.launch_monitors()
  30
  31         records = collections.defaultdict(list)
  32         last_records = {} # records indexed by process; used for comparison
  33
  34         for line in outpipe:
  35             record, process = self.get_record(line)
  36
  37             if not record:
  38                 continue
  39
  40             records[process].append(record)
  41
  42             if not process in last_records:
  43                 last_records[process] = record
  44                 continue
  45
  46             if (record['timestamp'] - last_records[process]['timestamp']).seconds <= 0:
  47                 continue
  48
  49             bw = self.get_bandwidth(last_records[process], record)
  50
  51             if not bw:
  52                 continue
  53
  54             last_records[process] = record
  55
  56             print '%10d / %10d B/s -- %s' % (bw[0], bw[1], process)
  57
  58
  59     def get_record(self, line):
  60         """
  61         parses the given line (output of runmonitor.py) and returns a record
  62         which is a dictionary with the keys timestamp, in and out (both in
  63         bytes)
  64         """
  65         match = self.line_regex.match(line)
  66
  67         if not match:
  68             return None, None
  69
  70         process = match.group('proc').strip()
  71         bytes_in = int(match.group('in'))
  72         bytes_out = int(match.group('out'))
  73         record = {'timestamp': datetime.now(), 'in': bytes_in, 'out': bytes_out}
  74         return record, process
  75
  76
  77     def get_bandwidth(self, rec1, rec2):
  78         """
  79         returns the mean incoming and outgoing bandwidth used between
  80         the two given records.
  81
  82         rec1 represents the earlier, rec2 the later record
  83         """
  84         date_diff = rec2['timestamp'] - rec1['timestamp']
  85         in_diff = rec2['in'] - rec1['in']
  86         out_diff = rec2['out'] - rec1['out']
  87
  88         if not date_diff.seconds:
  89             return None
  90
  91         in_bw = in_diff / date_diff.seconds
  92         out_bw = out_diff / date_diff.seconds
  93
  94         return (in_bw, out_bw)
  95