RRDtool.py

   1 #!/usr/bin/env python2
   2 # -*- coding: utf-8 -*-
   3 #
   4 #  rrdtool-py3k, rrdtool bindings for Python 3.
   5 #  Based on the rrdtool Python bindings for Python 2 from
   6 #  Hye-Shik Chang <perky@fallin.lv>.
   7 #
   8 #  Copyright 2012 Christian Jurk <commx@commx.ws>
   9 #
  10 #  This program is free software; you can redistribute it and/or modify
  11 #  it under the terms of the GNU Lesser General Public License as
  12 #  published by the Free Software Foundation; either version 3 of the
  13 #  License, or (at your option) any later version.
  14 #
  15 #  This program is distributed in the hope that it will be useful,
  16 #  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 #  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 #  GNU General Public License for more details.
  19 #
  20 #  You should have received a copy of the GNU Lesser General Public License
  21 #  along with this program; if not, write to the Free Software
  22 #  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  23 #  MA 02110-1301, USA.
  24 #
  25 #
  26
  27 from datetime import datetime
  28 from io import BytesIO
  29 import os
  30 import rrdtool
  31 from time import mktime
  32
  33 def create(filename, *args):
  34         "Create a Round Robin Database and return a RRD object on success."
  35         rrdtool.create(filename, *args)
  36
  37         if not os.access(filename, os.F_OK):
  38                 raise rrdtool.OperationalError('RRD file was not created')
  39
  40         return RRD(filename)
  41
  42 class RRD:
  43         """An object-based interface to the rrdtool module."""
  44
  45         def __init__(self, filename, check_type=True):
  46                 "Initialize the class instance with a filename."
  47
  48                 if not os.access(filename, os.F_OK | os.R_OK):
  49                         raise rrdtool.OperationalError('RRD {!s} cannot be opened.' \
  50                           .format(filename))
  51
  52                 # Use rrdinfo to test whether the file is a valid RRD file
  53                 if check_type is True:
  54                         rrdtool.info(filename)
  55
  56                 self.readonly = not os.access(filename, os.W_OK)
  57                 self.filename = filename
  58
  59         def graph(self, output_file, *args):
  60                 "Create a graph based on one or more RRDs."
  61                 buffered = True
  62                 outfile = '-'
  63
  64                 # write straigt into file using wrapper functions
  65                 if isinstance(output_file, str):
  66                         buffered = False
  67                         outfile = output_file
  68
  69                 gdata = rrdtool.graph(outfile, *args)
  70
  71                 if isinstance(gdata, tuple) and len(gdata) >= 4:
  72                         if output_file is None:
  73                                 return gdata[3]
  74                         elif isinstance(output_file, BytesIO):
  75                                 output_file.write(gdata[3])
  76                                 return output_file
  77
  78                 return None
  79
  80         def info(self):
  81                 return rrdtool.info(self.filename)
  82
  83         def update(self, values, *args):
  84                 vl = []
  85
  86                 if self.readonly:
  87                         raise rrdtool.OperationalError('RRD file is read-only: {!s}' \
  88                           .format(self.filename))
  89                 elif not isinstance(values, (list, tuple)):
  90                         raise rrdtool.ProgrammingError('The values parameter must be a ' \
  91                           'list or tuple')
  92                 else:
  93                         for row in values:
  94                                 if isinstance(row, str):
  95                                         vl.append(row)
  96                                 elif isinstance(row, (list, tuple)):
  97                                         if len(row) < 2:
  98                                                 raise rrdtool.ProgrammingError('Value {!r} has too ' \
  99                                                   'few elements in sequence object'.format(row))
 100                                         else:
 101                                                 ts = row[0]
 102                                                 if ts is None:
 103                                                         ts = 'N'
 104                                                 elif isinstance(ts, datetime):
 105                                                         ts = int(mktime(ts.timetuple()))
 106                                                 elif isinstance(ts, str):
 107                                                         ts = int(ts)
 108                                                 elif not isinstance(ts, int):
 109                                                         raise ValueError('Unsupported type')
 110
 111                                         v = '{}:{}'.format(ts, ':'.join([str(x) for x in row[1:]]))
 112                                         vl.append(v)
 113
 114                 arglist = tuple(vl + list(args))
 115                 return rrdtool.update(self.filename, *arglist)
 116
 117         def __repr__(self):
 118                 return '<RRD {!r}>'.format(self.filename)