#!/usr/bin/python
import os
import time
import json

from pprint import pprint

stats = "/proc/self/mountstats"
cache = "/tmp/%s-mountstats.cache" % os.getuid()

def parse_mountstats():
    mountstats = {"timestamp": time.time(), "datasets": {}}
    device = None
    ops = {}
    for line in [ line.strip().split() for line in open(stats).readlines() ]:
        if len(line) == 0: continue
    
        # New device
        if line[0] == "device" and line[7] == "nfs" and "/.zfs/" not in line[1] and "/.snapshots" not in line[1]:
            if device:
                mountstats["datasets"][device] = ops

            device = line[1]
            ops = {}

        if line[0] == "xprt:":
            ops.update ({'connect_count': int(line[4]), 'connect_time': int(line[5]), 'rpcsends': int(line[7]), 'rpcreceives': int(line[8]), 'backlogutil': int(line[11]) })
    
        if line[0] in ("READ:", "WRITE:"):
            operation = line[0][:-1].lower()
            ops.update({operation+'_ops': float(line[1]), operation+'_retrans': float(line[2]) - float(line[1]), operation+'_bytes': (float(line[4]) + float(line[5])) / 1024 / 1024, operation+'_exe_time': float(line[8])})
    if device:
        mountstats["datasets"][device] = ops
    return mountstats


if __name__ == '__main__':
    stats = parse_mountstats()
    diff = {}
    if not os.path.isfile(cache):
        open(cache, 'w').write(json.dumps(stats))
    else:
        try:
            old = json.loads(open(cache).read())
        except:
            pass
        else:
            timediff = stats["timestamp"] - old["timestamp"]
            for dataset, info in stats["datasets"].iteritems():
                diff[dataset] = {}
                for key, value in info.iteritems():
                    if old["datasets"].get(dataset, {}).get(key):
                        valuediff = value - old["datasets"].get(dataset, {}).get(key)
                        if valuediff == 0:
                            diff[dataset][key] = valuediff
                        else:
                            diff[dataset][key] = valuediff / timediff
        open(cache, 'w').write(json.dumps(stats))

    for dataset, info in diff.iteritems():
        print "0 stats-%s" % dataset, "|".join([ "%s=%s" % (x, y) for x, y in info.iteritems() ]), "OK"