check_net

#!/usr/bin/env python3
# check_net
# Reports Network Traffic for all interfaces
# Author: Anton Schubert <ischluff@mailbox.org>
# Version: 1.0
# Changelog:
#   2018-06-05 - 1.0 - Initial version
# Copyright (c) 2018
from __future__ import print_function
import os, sys, time, argparse, math, json
import re
from enum import IntEnum

class Status(IntEnum):
    OK = 0
    WARNING = 1
    CRITICAL = 2
    UNKNOWN = 3

def parse_net_stats(data):
    data = data.split("\n")

    results = {}
    for i in range(2, len(data) - 1):
        fields = re.split("\s+", data[i].strip())
        results[fields[0][:-1]] = {
            "rbytes": int(fields[1]),
            "tbytes": int(fields[9])
        }

    return results

def diff_samples(s1, s2, diff):
    results = {}
    for n2,d2 in s2.items():
        for n1,d1 in s1.items():
            if n1 == n2:
                results[n2] = dict((k, (d2[k]-d1[k]) / diff) for k in d2 if k in d1)
                break
    return results

# output total usage + usage per vm
def get_perfdata(results, diff):
    total_rxrate = sum(v["rbytes"] for n,v in results.items()) * 8 / 1024**2
    total_txrate = sum(v["tbytes"] for n,v in results.items()) * 8 / 1024**2
    perfdata = "Rx = {:.2f}Mbit/s, Tx = {:.2f}Mbit/s in {:.0f}s|".format(total_rxrate, total_txrate, diff)
    for name,value in results.items():
        perfdata += " {:}_rx={:.2f}B".format(name, value["rbytes"])
        perfdata += " {:}_tx={:.2f}B".format(name, value["tbytes"])
    return perfdata

# nagios compatible exit
def exit_status(status, perfdata="", message=None,):
    if message is not None:
        print("Net {:} - {:}".format(status.name, message))
    else:
        print("Net {:} - {:}".format(status.name, perfdata))

    sys.exit(status.value)

def main():
    histfile = "/tmp/.check_net"
    status = Status.OK
    parser = argparse.ArgumentParser(description="Reports Network Stats for all Interfaces")
    args = parser.parse_args()

    # get sample
    with open("/proc/net/dev", "r") as f:
        data = f.read()

    sample = parse_net_stats(data)
    now = time.time()

    # load history file
    try:
        stat = os.stat(histfile)
        past = stat.st_mtime
        with open(histfile) as f:
            previous_sample = json.load(f)

    except (IOError,OSError) as e:
        if e.errno == os.errno.ENOENT:
            status, message = Status.UNKNOWN, "History file not written yet"
        else:
            status, message = Status.UNKNOWN, "Failed to read the history file - {:}".format(e.strerror)

    # write history file
    with open(histfile, 'w') as f:
        json.dump(sample, f)

    # early exit on errors
    if status > Status.OK:
        exit_status(status, message)

    # compute values
    results = diff_samples(previous_sample, sample, now - past)

    # generate output
    exit_status(Status.OK, get_perfdata(results, now - past))

if __name__ == "__main__":
    main()