src/Ganeti/Storage/Diskstats/Parser.hs

{-# LANGUAGE OverloadedStrings #-}
{-| Diskstats proc file parser

This module holds the definition of the parser that extracts status
information about the disks of the system from the @/proc/diskstats@ file.

-}
{-

Copyright (C) 2013 Google Inc.
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2. Redistributions in binary form must reproduce the above copyright
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
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PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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-}
module Ganeti.Storage.Diskstats.Parser (diskstatsParser) where

import Control.Applicative ((<*>), (<*), (<$>))
import qualified Data.Attoparsec.Text as A
import qualified Data.Attoparsec.Combinator as AC
import Data.Attoparsec.Text (Parser)

import Ganeti.Parsers
import Ganeti.Storage.Diskstats.Types

-- * Parser implementation

-- | The parser for one line of the diskstatus file.
oneDiskstatsParser :: Parser Diskstats
oneDiskstatsParser =
  let majorP = numberP
      minorP = numberP
      nameP = stringP
      readsNumP = numberP
      mergedReadsP = numberP
      secReadP = numberP
      timeReadP = numberP
      writesP = numberP
      mergedWritesP = numberP
      secWrittenP = numberP
      timeWriteP = numberP
      iosP = numberP
      timeIOP = numberP
      wIOmillisP = numberP
  in
    Diskstats <$> majorP <*> minorP <*> nameP <*> readsNumP <*> mergedReadsP
      <*> secReadP <*> timeReadP <*> writesP <*> mergedWritesP <*> secWrittenP
      <*> timeWriteP <*> iosP <*> timeIOP <*> wIOmillisP <* A.endOfLine

-- | The parser for a whole diskstatus file.
diskstatsParser :: Parser [Diskstats]
diskstatsParser = oneDiskstatsParser `AC.manyTill` A.endOfInput