!/usr/bin/env python

import os
import mmap
import struct
import signal
import optparse

try:
import whisper
except ImportError:
raise SystemExit('[ERROR] Please make sure whisper is installed properly')

Ignore SIGPIPE

signal.signal(signal.SIGPIPE, signal.SIG_DFL)

option_parser = optparse.OptionParser(usage='''%prog path''')
(options, args) = option_parser.parse_args()

if len(args) != 1:
option_parser.error("require one input file name")
else:
path = args[0]

def mmap_file(filename):
fd = os.open(filename, os.O_RDONLY)
map = mmap.mmap(fd, os.fstat(fd).st_size, prot=mmap.PROT_READ)
os.close(fd)
return map

def read_header(map):
try:
(aggregationType,maxRetention,xFilesFactor,archiveCount) = struct.unpack(whisper.metadataFormat,map[:whisper.metadataSize])
except:
raise CorruptWhisperFile("Unable to unpack header")

archives = []
archiveOffset = whisper.metadataSize

for i in xrange(archiveCount):
try:
(offset, secondsPerPoint, points) = struct.unpack(whisper.archiveInfoFormat, map[archiveOffset:archiveOffset+whisper.archiveInfoSize])
except:
raise CorruptWhisperFile("Unable to read archive %d metadata" % i)

archiveInfo = {
  'offset' : offset,
  'secondsPerPoint' : secondsPerPoint,
  'points' : points,
  'retention' : secondsPerPoint * points,
  'size' : points * whisper.pointSize,
}
archives.append(archiveInfo)
archiveOffset += whisper.archiveInfoSize

header = {
'aggregationMethod' : whisper.aggregationTypeToMethod.get(aggregationType, 'average'),
'maxRetention' : maxRetention,
'xFilesFactor' : xFilesFactor,
'archives' : archives,
}
return header

def dump_header(header):
print 'Meta data:'
print ' aggregation method: %s' % header['aggregationMethod']
print ' max retention: %d' % header['maxRetention']
print ' xFilesFactor: %g' % header['xFilesFactor']
print
dump_archive_headers(header['archives'])

def dump_archive_headers(archives):
for i,archive in enumerate(archives):
print 'Archive %d info:' % i
print ' offset: %d' % archive['offset']
print ' seconds per point: %d' % archive['secondsPerPoint']
print ' points: %d' % archive['points']
print ' retention: %d' % archive['retention']
print ' size: %d' % archive['size']
print

def dump_archives(archives):
for i,archive in enumerate(archives):
print 'Archive %d data:' %i
offset = archive['offset']
for point in xrange(archive['points']):
(timestamp, value) = struct.unpack(whisper.pointFormat, map[offset:offset+whisper.pointSize])
print '%d: %d, %10.35g' % (point, timestamp, value)
offset += whisper.pointSize
print

if not os.path.exists(path):
raise SystemExit('[ERROR] File "%s" does not exist!' % path)

map = mmap_file(path)
header = read_header(map)
dump_header(header)
dump_archives(header['archives'])