#!/usr/bin/env python
import re
import nagios
import socket
import signal
import string

import sys

# default port number
PORT=3121
# default timeout
TIMEOUT=10

# exception raised when timeout occurs
TimeoutException = "Timeout"

#################### comon-based acquisition
def check (hostname, timeout=None):

#    print "Entering comon_sensor::check",hostname

    if (timeout == None):
        timeout=TIMEOUT

    try:
        # connect to comon and read data
        page = read_data (hostname,timeout)
        # parse lines and store in dict
        dict = parse_data (page)
        # keep only relevant stuff and refine parsing
        dict = filter (dict)
        # make decision
        return interpret (dict)

    except TimeoutException:
        print "While connecting to comon sensor : timeout expired %d s"%timeout
        ### XXX - in some cases this is a KO, but in general
        # maybe comon does not run on these nodes
        return nagios.UNKNOWN

### implement timeout as an alarm signal
def alarm_handler(s,closure):
    if s == signal.SIGALRM:
        raise TimeoutException
    else:
        print "unexpected signal s in alarm_handler"

###
# returns a list of lines
# dont use httplib nor urllib2
# the server side replies its data even before you send a GET request
# with urllib2 you basically get a 'Connection reset by peer' error
def read_data (hostname,timeout,port=None):

    if (port ==None):
        port=PORT

    signal.signal(signal.SIGALRM,alarm_handler)
    signal.alarm(timeout)
    s =socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((hostname,port))
    signal.alarm(0)
    
    lines=[]
    line=""
    while 1:
        char=s.recv(1)
        if not char:
            break
        elif char == '\n':
            lines += [line]
            line=""
        else:
            line+=char
    return lines

### pattern for interpreting sensor output
re_line="^([a-zA-Z0-9_]+): (.*)$"
ma_line=re.compile(re_line)

def parse_data (page):
    dict={}
    for line in page:
        matched=ma_line.match(line)
        if matched:
            key,val=matched.groups()
            dict[key]=val
    return dict
        
FIELDS_FOCUS = {
    'Loads':'floats',
    'VMStat':'ints',
    'CPUUse':'ints',
    'MemInfo':'floats',
    'Date':'floats',
    'DfDot':'percent-floats',
    'LastSsh':'ints',
    }


def filter (dict):

    filtered = {}
    for key in dict.keys():
        if key in FIELDS_FOCUS.keys():
            format=FIELDS_FOCUS[key]
            value=dict[key].rstrip()
            if format == 'ints':
                filtered[key]=map(int,value.split(' '))
            elif format == 'floats':
                filtered[key]=map(float,value.split(' '))
            elif format == 'percent-floats':
                fields=value.split()
                pval=string.replace(fields[0],'%','')
                filtered[key]=map(float,[pval]+fields[1:])
            # simpler access to single-fields
            value = filtered[key]
            if len(value)==1:
                filtered[key]=value[0]
    return filtered

def interpret (dict):

    status = nagios.OK

    ### check ssh status
    ssh_delay = dict['Date']- dict['LastSsh']
    print ssh_delay

    ### 
    return status

###
def usage():
    print "Usage comon_sensor.py node timeout"
    sys.exit(1)

if __name__=='__main__':
    if len(sys.argv) != 3:
        usage()
    check(sys.argv[1],int(sys.argv[2]))