"""
Look through ZFS logs to find latest scrub and its output.
Note that ZFS doesn't normally produce logs in /var/log, so for this to
work, we must set up a cron job to dump `zpool iostat` into a file (hourly is 
best):
    `zpool iostat > /var/log/zpool.log && zpool status >> /var/log/zpool.log`

The file gets overwritten every hour, so if more than one scrub occurs
between logparse runs, it will only get the latest one.

TODO: add feature to specify pools to check in config file
TODO: set critical value for scrub data repair
"""

import re
import sys, traceback

from logparse.formatting import *
from logparse.util import readlog
from logparse.config import prefs
from logparse.load_parsers import Parser

class Zfs(Parser):

    def __init__(self):
        super().__init__()
        self.name = "zfs"
        self.info = "Look through ZFS logs to find latest scrub and its output"

    def parse_log(self):

        logger.debug("Starting zfs section")
        section = Section("zfs")

        zfslog = readlog(prefs.get("logs", "zfs"))

        logger.debug("Analysing zpool log")
        pool = re.search('.*---\n(\w*)', zfslog).group(1)
        scrub = re.search(".* scrub repaired (\d+\s*\w+) in .* with (\d+) "
                "errors on (\w+)\s+(\w+)\s+(\d+)\s+(\d{1,2}:\d{2}):"
                "\d+\s+(\d{4})", zfslog)
        logger.debug("Found groups {0}".format(scrub.groups()))
        iostat = re.search('.*---\n\w*\s*(\S*)\s*(\S*)\s', zfslog)
        scrubrepairs = scruberrors = scrubdate = None
        alloc = iostat.group(1)
        free = iostat.group(2)

        try:
            scrubrepairs = scrub.group(1)
            scruberrors = scrub.group(2)
            scrubdate = ' '.join(scrub.groups()[2:-1])
        except Exception as e:
            logger.debug("Error getting scrub data: " + str(e))
            traceback.print_exc(limit=2, file=sys.stdout)

        if (scrubdate != None):
            scrub_data = Data("Scrub of " + pool + " on " + scrubdate)
            scrub_data.items = [scrubrepairs + " repaired",
                    scruberrors + " errors", alloc + " used", free + " free"]
        else:
            scrub_data = Data(pool)
            scrub_data.items = [alloc + " used", free + " free"]

        section.append_data(scrub_data)

        logger.info("Finished zfs section")
        return section