以下是我尝试从rrd文件生成json的代码.

Following is the code I tried for generating json from rrd file.

#!/usr/bin/python
import rrdtool
import sys

def printMetric():

  args = ["/var/lib/ganglia/rrds/__SummaryInfo__/cpu_system.rrd", "AVERAGE"]
  rrdMetric = rrdtool.fetch(args)

  time = rrdMetric[0][0]
  step = rrdMetric[0][2]

  sys.stdout.write("  {\n    \"Key1\":\"" + rrdMetric[1][0] +\
                   "\",\n    \"Key2\":\"" + "abcd" +\
                   "\",\n    \"metric_name\":\"" + "cpu_system" + "\",\n")  

  firstDP = True
  sys.stdout.write("    \"datapoints\":[\n")
  for tuple in rrdMetric[2]:
    if tuple[0] is not None:
      if not firstDP:
        sys.stdout.write(",\n")
      firstDP = False
      sys.stdout.write("      [")
      sys.stdout.write(str(tuple[0]))
      sys.stdout.write(",")
      sys.stdout.write(str(time))
      sys.stdout.write("]")
    time = time + step
  sys.stdout.write("\n    ]\n  }")

printMetric()