content: {-| Logical Volumes data collector.
  
  -}
  
  {-
  
  Copyright (C) 2013 Google Inc.
  All rights reserved.
  
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  modification, are permitted provided that the following conditions are
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  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
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  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.Lv
    ( main
    , options
    , arguments
    , dcName
    , dcVersion
    , dcFormatVersion
    , dcCategory
    , dcKind
    , dcReport
    ) where
  
  
  import Control.Monad
  import Data.Attoparsec.Text.Lazy as A
  import Data.List
  import Data.Maybe (mapMaybe)
  import Data.Text.Lazy (pack, unpack)
  import Network.BSD (getHostName)
  import System.Process
  import System.IO.Error (tryIOError)
  import qualified Text.JSON as J
  
  import qualified Ganeti.BasicTypes as BT
  import Ganeti.Common
  import qualified Ganeti.Constants as C
  import Ganeti.Confd.ClientFunctions
  import Ganeti.DataCollectors.CLI
  import Ganeti.DataCollectors.Types
  import Ganeti.JSON (fromJResult)
  import Ganeti.Objects
  import Ganeti.Storage.Lvm.LVParser
  import Ganeti.Storage.Lvm.Types
  import Ganeti.Utils
  
  
  -- | 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.dataCollectorLv
  
  -- | 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 = DCKPerf
  
  -- | The data exported by the data collector, taken from the default location.
  dcReport :: IO DCReport
  dcReport = buildDCReport defaultOptions
  
  -- * Command line options
  
  options :: IO [OptType]
  options =
    return
      [ oInputFile
      , oConfdAddr
      , oConfdPort
      , oInstances
      ]
  
  -- | The list of arguments supported by the program.
  arguments :: [ArgCompletion]
  arguments = [ArgCompletion OptComplFile 0 (Just 0)]
  
  -- | Get information about logical volumes from file (if specified) or
  -- by actually running the command to get it from a live cluster.
  getLvInfo :: Maybe FilePath -> IO [LVInfo]
  getLvInfo inputFile = do
    let cmd = lvCommand
        params = lvParams
        fromLvs =
          tryIOError (readProcess cmd params "") >>=
          exitIfBad "running command" . either (BT.Bad . show) BT.Ok
    contents <-
      maybe fromLvs (\fn -> tryIOError (readFile fn)
        >>= exitIfBad "reading from file" . either (BT.Bad . show) BT.Ok)
        inputFile
    case A.parse lvParser $ pack contents of
      A.Fail unparsedText contexts errorMessage -> exitErr $
        show (Prelude.take defaultCharNum $ unpack unparsedText) ++ "\n"
          ++ show contexts ++ "\n" ++ errorMessage
      A.Done _ lvinfoD -> return lvinfoD
  
  -- | Get the list of real instances on the current node along with their disks,
  -- either from a provided file or by querying Confd.
  getInstDiskList :: Options -> IO [(RealInstanceData, [Disk])]
  getInstDiskList opts = do
    instances <- maybe fromConfd fromFile $ optInstances opts
    exitIfBad "Unable to obtain the list of instances" instances
    where
      fromConfdUnchecked :: IO (BT.Result [(RealInstanceData, [Disk])])
      fromConfdUnchecked = do
        let srvAddr = optConfdAddr opts
            srvPort = optConfdPort opts
            toReal (RealInstance i, dsks) = Just (i, dsks)
            toReal _ = Nothing
        getHostName >>= \n -> BT.runResultT
                              . liftM (mapMaybe toReal)
                              $ getInstanceDisks n srvAddr srvPort
  
      fromConfd :: IO (BT.Result [(RealInstanceData, [Disk])])
      fromConfd =
        liftM (either (BT.Bad . show) id)
        (tryIOError fromConfdUnchecked)
  
      fromFile :: FilePath -> IO (BT.Result [(RealInstanceData, [Disk])])
      fromFile inputFile = do
        contents <-
          tryIOError (readFile inputFile)
          >>= exitIfBad "reading from file" . either (BT.Bad . show) BT.Ok
        return . fromJResult "Not a list of instances" $ J.decode contents
  
  -- | Adds the name of the instance to the information about one logical volume.
  addInstNameToOneLv :: [(RealInstanceData, [Disk])] -> LVInfo -> LVInfo
  addInstNameToOneLv instDiskList lvInfo =
   let lv = LogicalVolume (lviVgName lvInfo) (lviName lvInfo)
       instanceHasDisk = any (includesLogicalId lv) . snd
       rightInstance = find instanceHasDisk instDiskList
     in
       case rightInstance of
         Nothing -> lvInfo
         Just (i, _) -> lvInfo { lviInstance = Just $ realInstName i }
  
  -- | Adds the name of the instance to the information about logical volumes.
  addInstNameToLv :: [(RealInstanceData, [Disk])] -> [LVInfo] -> [LVInfo]
  addInstNameToLv instDisksList = map (addInstNameToOneLv instDisksList)
  
  -- | This function computes the JSON representation of the LV status.
  buildJsonReport :: Options -> IO J.JSValue
  buildJsonReport opts = do
    let inputFile = optInputFile opts
    lvInfo <- getLvInfo inputFile
    instDiskList <- getInstDiskList opts
    return . J.showJSON $ addInstNameToLv instDiskList lvInfo
  
  -- | This function computes the DCReport for the logical volumes.
  buildDCReport :: Options -> IO DCReport
  buildDCReport opts =
    buildJsonReport opts >>=
      buildReport dcName dcVersion dcFormatVersion dcCategory dcKind
  
  -- | Main function.
  main :: Options -> [String] -> IO ()
  main opts args = do
    unless (null args) . exitErr $ "This program takes exactly zero" ++
                                   " arguments, got '" ++ unwords args ++ "'"
  
    report <- buildDCReport opts
    putStrLn $ J.encode report
  