content: {-| DRBD data collector.
  
  -}
  
  {-
  
  Copyright (C) 2012, 2013 Google Inc.
  All rights reserved.
  
  Redistribution and use in source and binary forms, with or without
  modification, are permitted provided that the following conditions are
  met:
  
  1. Redistributions of source code must retain the above copyright notice,
  this list of conditions and the following disclaimer.
  
  2. Redistributions in binary form must reproduce the above copyright
  notice, this list of conditions and the following disclaimer in the
  documentation and/or other materials provided with the distribution.
  
  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  -}
  
  module Ganeti.DataCollectors.Drbd
    ( main
    , options
    , arguments
    , dcName
    , dcVersion
    , dcFormatVersion
    , dcCategory
    , dcKind
    , dcReport
    ) where
  
  
  import System.IO.Error (tryIOError)
  import Control.Monad
  import Data.Attoparsec.Text.Lazy as A
  import Data.List
  import Data.Maybe
  import Data.Text.Lazy (pack, unpack)
  import Network.BSD (getHostName)
  import qualified Text.JSON as J
  
  import qualified Ganeti.BasicTypes as BT
  import qualified Ganeti.Constants as C
  import Ganeti.Storage.Drbd.Parser(drbdStatusParser)
  import Ganeti.Storage.Drbd.Types
  import Ganeti.Common
  import Ganeti.Confd.Client
  import Ganeti.Confd.Types
  import Ganeti.DataCollectors.CLI
  import Ganeti.DataCollectors.Types
  import Ganeti.Utils
  
  
  -- | The default path of the DRBD status file.
  -- It is hardcoded because it is not likely to change.
  defaultFile :: FilePath
  defaultFile = C.drbdStatusFile
  
  -- | The default setting for the maximum amount of not parsed character to
  -- print in case of error.
  -- It is set to use most of the screen estate on a standard 80x25 terminal.
  -- TODO: add the possibility to set this with a command line parameter.
  defaultCharNum :: Int
  defaultCharNum = 80*20
  
  -- | The name of this data collector.
  dcName :: String
  dcName = C.dataCollectorDrbd
  
  -- | The version of this data collector.
  dcVersion :: DCVersion
  dcVersion = DCVerBuiltin
  
  -- | The version number for the data format of this data collector.
  dcFormatVersion :: Int
  dcFormatVersion = 1
  
  -- | The category of this data collector.
  dcCategory :: Maybe DCCategory
  dcCategory = Just DCStorage
  
  -- | The kind of this data collector.
  dcKind :: DCKind
  dcKind = DCKStatus
  
  -- | The data exported by the data collector, taken from the default location.
  dcReport :: IO DCReport
  dcReport = buildDCReport defaultFile Nothing
  
  -- * Command line options
  
  options :: IO [OptType]
  options =
    return
      [ oDrbdStatus
      , oDrbdPairing
      ]
  
  -- | The list of arguments supported by the program.
  arguments :: [ArgCompletion]
  arguments = [ArgCompletion OptComplFile 0 (Just 0)]
  
  -- | Get information about the pairing of DRBD minors and Ganeti instances
  -- on the current node. The information is taken from the Confd client
  -- or, if a filename is specified, from a JSON encoded file (for testing
  -- purposes).
  getPairingInfo :: Maybe String -> IO (BT.Result [DrbdInstMinor])
  getPairingInfo Nothing = do
    curNode <- getHostName
    client <- getConfdClient Nothing Nothing
    reply <- query client ReqNodeDrbd $ PlainQuery curNode
    return $
      case fmap (J.readJSONs . confdReplyAnswer) reply of
        Just (J.Ok instMinor) -> BT.Ok instMinor
        Just (J.Error msg) -> BT.Bad msg
        Nothing -> BT.Bad "No answer from the Confd server"
  getPairingInfo (Just filename) = do
    content <- readFile filename
    return $
      case J.decode content of
        J.Ok instMinor -> BT.Ok instMinor
        J.Error msg -> BT.Bad msg
  
  -- | Compute the status code and message, given the current DRBD data
  -- The final state will have the code corresponding to the worst code of
  -- all the devices, and the error message given from the concatenation of the
  -- non-empty error messages.
  computeStatus :: DRBDStatus -> DCStatus
  computeStatus (DRBDStatus _ devInfos) =
    let statuses = map computeDevStatus devInfos
        (code, strList) = foldr mergeStatuses (DCSCOk, [""]) statuses
    in DCStatus code $ intercalate "\n" strList
  
  -- | Compute the status of a DRBD device and its error message.
  computeDevStatus :: DeviceInfo -> (DCStatusCode, String)
  computeDevStatus (UnconfiguredDevice _) = (DCSCOk, "")
  computeDevStatus dev =
    let errMsg s = show (minorNumber dev) ++ ": " ++ s
        compute_helper StandAlone =
          (DCSCBad, errMsg "No network config available")
        compute_helper Disconnecting =
          (DCSCBad, errMsg "The peer is being disconnected")
        compute_helper Unconnected =
          (DCSCTempBad, errMsg "Trying to establish a network connection")
        compute_helper Timeout =
          (DCSCTempBad, errMsg "Communication problems between the peers")
        compute_helper BrokenPipe =
          (DCSCTempBad, errMsg "Communication problems between the peers")
        compute_helper NetworkFailure =
          (DCSCTempBad, errMsg "Communication problems between the peers")
        compute_helper ProtocolError =
          (DCSCTempBad, errMsg "Communication problems between the peers")
        compute_helper TearDown =
          (DCSCBad, errMsg "The peer is closing the connection")
        compute_helper WFConnection =
          (DCSCTempBad, errMsg "Trying to establish a network connection")
        compute_helper WFReportParams =
          (DCSCTempBad, errMsg "Trying to establish a network connection")
        compute_helper Connected = (DCSCOk, "")
        compute_helper StartingSyncS = (DCSCOk, "")
        compute_helper StartingSyncT = (DCSCOk, "")
        compute_helper WFBitMapS = (DCSCOk, "")
        compute_helper WFBitMapT = (DCSCOk, "")
        compute_helper WFSyncUUID = (DCSCOk, "")
        compute_helper SyncSource = (DCSCOk, "")
        compute_helper SyncTarget = (DCSCOk, "")
        compute_helper PausedSyncS = (DCSCOk, "")
        compute_helper PausedSyncT = (DCSCOk, "")
        compute_helper VerifyS = (DCSCOk, "")
        compute_helper VerifyT = (DCSCOk, "")
        compute_helper Unconfigured = (DCSCOk, "")
    in compute_helper $ connectionState dev
  
  -- | This function computes the JSON representation of the DRBD status.
  buildJsonReport :: FilePath -> Maybe FilePath -> IO J.JSValue
  buildJsonReport statusFile pairingFile = do
    contents <-
      tryIOError (readFile statusFile) >>=
        exitIfBad "reading from file" . either (BT.Bad . show) BT.Ok
    pairingResult <- getPairingInfo pairingFile
    pairing <- logWarningIfBad "Can't get pairing info" [] pairingResult
    drbdData <-
      case A.parse (drbdStatusParser pairing) $ pack contents of
        A.Fail unparsedText contexts errorMessage -> exitErr $
          show (Prelude.take defaultCharNum $ unpack unparsedText) ++ "\n"
            ++ show contexts ++ "\n" ++ errorMessage
        A.Done _ drbdS -> return drbdS
    let status = computeStatus drbdData
    return . addStatus status $ J.showJSON drbdData
  
  -- | This function computes the DCReport for the DRBD status.
  buildDCReport :: FilePath -> Maybe FilePath -> IO DCReport
  buildDCReport statusFile pairingFile =
    buildJsonReport statusFile pairingFile >>=
      buildReport dcName dcVersion dcFormatVersion dcCategory dcKind
  
  -- | Main function.
  main :: Options -> [String] -> IO ()
  main opts args = do
    let statusFile = fromMaybe defaultFile $ optDrbdStatus opts
        pairingFile = optDrbdPairing opts
    unless (null args) . exitErr $ "This program takes exactly zero" ++
                                    " arguments, got '" ++ unwords args ++ "'"
    report <- buildDCReport statusFile pairingFile
    putStrLn $ J.encode report
  