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{-| External data loader.

This module holds the external data loading, and thus is the only one

depending (via the specialized Text\/Rapi\/Luxi modules) on the actual

libraries implementing the low-level protocols.

-}

{-

Copyright (C) 2009, 2010, 2011 Google Inc.

This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; either version 2 of the License, or

(at your option) any later version.

This program is distributed in the hope that it will be useful, but

WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

02110-1301, USA.

-}

module Ganeti.HTools.ExtLoader

  ( loadExternalData

  , commonSuffix

  , maybeSaveData

  ) where

import Control.Monad

import Data.Maybe (isJust, fromJust)

import System.FilePath

import System.IO

import System.Exit

import Text.Printf (hPrintf)

import qualified Ganeti.HTools.Luxi as Luxi

import qualified Ganeti.HTools.Rapi as Rapi

import qualified Ganeti.HTools.Simu as Simu

import qualified Ganeti.HTools.Text as Text

import Ganeti.HTools.Loader (mergeData, checkData, ClusterData(..)

                            , commonSuffix)

import Ganeti.HTools.Types

import Ganeti.HTools.CLI

import Ganeti.HTools.Utils (sepSplit, tryRead)

-- | Error beautifier.

wrapIO :: IO (Result a) -> IO (Result a)

wrapIO = flip catch (return . Bad . show)

-- | Parses a user-supplied utilisation string.

parseUtilisation :: String -> Result (String, DynUtil)

parseUtilisation line =

  case sepSplit ' ' line of

    [name, cpu, mem, dsk, net] ->

      do

        rcpu <- tryRead name cpu

        rmem <- tryRead name mem

        rdsk <- tryRead name dsk

        rnet <- tryRead name net

        let du = DynUtil { cpuWeight = rcpu, memWeight = rmem

                         , dskWeight = rdsk, netWeight = rnet }

        return (name, du)

    _ -> Bad $ "Cannot parse line " ++ line

-- | External tool data loader from a variety of sources.

loadExternalData :: Options

                 -> IO ClusterData

loadExternalData opts = do

  let mhost = optMaster opts

      lsock = optLuxi opts

      tfile = optDataFile opts

      simdata = optNodeSim opts

      setRapi = mhost /= ""

      setLuxi = isJust lsock

      setSim = (not . null) simdata

      setFile = isJust tfile

      allSet = filter id [setRapi, setLuxi, setFile]

      exTags = case optExTags opts of

                 Nothing -> []

                 Just etl -> map (++ ":") etl

      selInsts = optSelInst opts

      exInsts = optExInst opts

  when (length allSet > 1) $

       do

         hPutStrLn stderr ("Error: Only one of the rapi, luxi, and data" ++

                           " files options should be given.")

         exitWith $ ExitFailure 1

  util_contents <- maybe (return "") readFile (optDynuFile opts)

  let util_data = mapM parseUtilisation $ lines util_contents

  util_data' <- case util_data of

                  Ok x  -> return x

                  Bad y -> do

                    hPutStrLn stderr ("Error: can't parse utilisation" ++

                                      " data: " ++ show y)

                    exitWith $ ExitFailure 1

  input_data <-

    case () of

      _ | setRapi -> wrapIO $ Rapi.loadData mhost

        | setLuxi -> wrapIO $ Luxi.loadData $ fromJust lsock

        | setSim -> Simu.loadData simdata

        | setFile -> wrapIO $ Text.loadData $ fromJust tfile

        | otherwise -> return $ Bad "No backend selected! Exiting."

  let ldresult = input_data >>= mergeData util_data' exTags selInsts exInsts

  cdata <-

    case ldresult of

      Ok x -> return x

      Bad s -> do

        hPrintf stderr

          "Error: failed to load data, aborting. Details:\n%s\n" s:: IO ()

        exitWith $ ExitFailure 1

  let (fix_msgs, nl) = checkData (cdNodes cdata) (cdInstances cdata)

  unless (optVerbose opts == 0) $ maybeShowWarnings fix_msgs

  return cdata {cdNodes = nl}

-- | Function to save the cluster data to a file.

maybeSaveData :: Maybe FilePath -- ^ The file prefix to save to

              -> String         -- ^ The suffix (extension) to add

              -> String         -- ^ Informational message

              -> ClusterData    -- ^ The cluster data

              -> IO ()

maybeSaveData Nothing _ _ _ = return ()

maybeSaveData (Just path) ext msg cdata = do

  let adata = Text.serializeCluster cdata

      out_path = path <.> ext

  writeFile out_path adata

  hPrintf stderr "The cluster state %s has been written to file '%s'\n"

          msg out_path