今天介紹將記憶體使用情況匯製圖形的Python程式.
程式碼如下:

#!/usr/bin/env python
# ---------------------------
# Python RRDTool 
# Memory Data
# Create Image from rrd file
# ---------------------------

import rrdtool
import datetime

def mem_graph(rrdfile, period):
    timenow = datetime.datetime.now()
    disptime = datetime.datetime.strftime(timenow, '%Y-%m-d %H-%M-%S')
    title = 'Memory_Usage_' + period
    filename = title + '.png'
    
    # -------------------
    mfree = 'DEF:mfree=%s:mfree:AVERAGE' % rrdfile
    mbuff = 'DEF:mbuff=%s:mbuff:AVERAGE' % rrdfile
    mcach = 'DEF:mcach=%s:mcach:AVERAGE' % rrdfile
    mtotl = 'DEF:mtotl=%s:mtotl:AVERAGE' % rrdfile
    mused = 'CDEF:mused=mtotl,mfree,-'  
    # -------------------
    if period == 'yesterday':
        start = 'end-1d'
        end = '00:00'
    if period == 'today':
        start = '00:00'
        end = '23:59'
    if period == '2h':
        start = '-2h'
        end = 'now'
        
    rrdtool.graph(
        filename,
        '--start', start,
        '--end', end,
        '--title', title,
        '-a', 'PNG',
        '-W', 'Hitomitanaka for ITHelp',
        '--slope-mode',
        '--vertical-label=K Bytes',
        '--rigid',
        '--lower-limit', '0',
        '--width', '500',
        '--height', '150',
        '--x-grid', 'HOUR:1:HOUR:2:HOUR:2:0:%H',
        '--alt-y-grid',
        '--color', 'BACK#000000',
        '--color', 'CANVAS#000000',
        '--color', 'FONT#FFF978',
        '--font=LEGEND:7',
        '--font', 'TITLE:8:',
        '--font', 'UNIT:7:',
        '--font', 'WATERMARK:9',
        # ---------------------------------
        mcach,
        mfree,
        mbuff,
        mtotl,
        mused,
        #----------------------------------
        'AREA:mused#4444EE:Used',
        'GPRINT:mused:LAST:  Current\\: %.01lf',
        'GPRINT:mused:AVERAGE:   Average\\: %.01lf',
        'GPRINT:mused:MIN:   Min\\: %.01lf',
        'GPRINT:mused:MAX:   Max\\: %.01lf\\n',
        'AREA:mcach#EEEE00:Cached',
        'GPRINT:mcach:LAST:Current\\: %.01lf',
        'GPRINT:mcach:AVERAGE:   Average\\: %.01lf',
        'GPRINT:mcach:MIN:   Min\\: %.01lf',
        'GPRINT:mcach:MAX:   Max\\: %.01lf\\n',
        'AREA:mbuff#EE4444:Buffer',
        'GPRINT:mbuff:LAST:Current\\: %.01lf',
        'GPRINT:mbuff:AVERAGE:     Average\\: %.01lf',
        'GPRINT:mbuff:MIN:     Min\\: %.01lf',
        'GPRINT:mbuff:MAX:     Max\\: %.01lf\\n',
        'COMMENT:\t\t\t\tUpdate Time %s' % disptime)
#
if __name__ == '__main__':
    mem_graph('memory.rrd', 'today')
    mem_graph('memory.rrd', 'yesterday')

圖形如下: