#!/usr/bin/env python

from pygtail import Pygtail
from datadog import statsd
import re

# nginx.net.response_time
# statsd.histogram('', duration)

# nginx.net.response_codes.<x>
# nginx.net.method.<x>
# nginx.net.cache.<hit|miss>
# statsd.increment

log_file = '/var/log/nginx/spfoodie-access.log'
# sample_line = ('127.0.0.1 - MISS - [19/Mar/2015:22:25:16 +0000] '
#             '"GET /stub-status HTTP/1.1" 404 32276 0.332 "-" "curl/7.35.0"')
sample_line = (
    '127.0.0.1 - - - [20/Mar/2015:08:51:16 -0400] "PURGE /vampire-cocktail/'
    'HTTP/1.1" 200 23122 0.509 "http://pinterest.com/pin/462111611740773604/'
    '?source_app=android" "Mozilla/5.0 '
    '(Linux; U; Android 4.1.2; el-gr; ST26i Build/11.2.A.0.31) '
    'AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 '
    'Mobile Safari/534.30 mod_pagespeed/1.8.31.5-4307"'
)

name_prefix = 'nginx.net'

statsd_type = {
    'response_code': 'increment',
    'method': 'increment',
    'cache': 'increment',
    'response_time': 'histogram',
    'bytes_sent': 'histogram'
}

log_re = re.compile(
    (r''
     '(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}) '
     '- (?P<cache>(-|\w+)) - '
     '\[(\d{2}\/[a-z]{3}\/\d{4}:\d{2}:\d{2}:\d{2} '
     '(\+|\-)\d{4})\] '
     '((\"(?P<method>\w+) )(?P<url>.+)(http\/\d\.\d\")) '
     '(?P<response_code>\d{3}) '
     '(?P<bytes_sent>\d+) '
     '(?P<response_time>\d+\.\d+) '
     '(["]((\-)|(.+))["]) '
     '(["](.+)["])'),
    re.IGNORECASE)


def parse_line(line):
    """ Given a log line, returns a dict of values
        cache: (hit || miss)
        method (GET, POST, PUT, PURGE, ...)
        response_time: (seconds)
        response_code: (404, 302, ...)
        bytes_sent: <int>
    """
    match = log_re.match(line.strip())
    if not match:
        return None
    else:
        return match.groupdict()


def main():
    """ Pull unprocessed lines from a log file.
        For each line and each extracted metric, submit the data.
    """

    for line in Pygtail(log_file):
        data = parse_line(line)
        if not data:
            print "Error parsing {0}".format(line)
            continue

        if data['cache'] == '-':
            data['cache'] = 'disabled'

        for k, v in data.iteritems():
            if k in statsd_type:
                if statsd_type[k] == 'increment':
                    metric_name = "{0}.{1}.{2}".format(
                        name_prefix,
                        k,
                        v.lower())
                    statsd.increment(metric_name)
                elif statsd_type[k] == 'histogram':
                    metric_name = "{0}.{1}".format(name_prefix, k)
                    statsd.histogram(metric_name, v)


def test():
    print parse_line(sample_line)

if __name__ == '__main__':
    main()
    # test()