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{-| Instance status data collector.

-}

{-

Copyright (C) 2013 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.DataCollectors.InstStatus

  ( main

  , options

  , arguments

  ) where

import Control.Exception.Base

import Data.Maybe

import qualified Data.Map as Map

import Network.BSD (getHostName)

import qualified Text.JSON as J

import qualified Ganeti.BasicTypes as BT

import Ganeti.Confd.Client

import Ganeti.Confd.Types

import Ganeti.Common

import Ganeti.DataCollectors.CLI

import Ganeti.DataCollectors.InstStatusTypes

import Ganeti.DataCollectors.Types

import Ganeti.Hypervisor.Xen

import Ganeti.Hypervisor.Xen.Types

import Ganeti.Logging

import Ganeti.Objects

import Ganeti.Path

import Ganeti.Types

import Ganeti.Utils

-- * Command line options

options :: IO [OptType]

options = return

  [ oConfdAddr

  , oConfdPort

  ]

-- | The list of arguments supported by the program.

arguments :: [ArgCompletion]

arguments = []

-- | Get the list of instances ([primary], [secondary]) on the given node.

-- Implemented as a function, even if used a single time, to specify in a

-- convenient and elegant way the return data type, required in order to

-- prevent incurring in the monomorphism restriction.

-- The server address and the server port parameters are mainly intended

-- for testing purposes. If they are Nothing, the default values will be used.

getInstances

  :: String

  -> Maybe String

  -> Maybe Int

  -> IO (BT.Result ([Ganeti.Objects.Instance], [Ganeti.Objects.Instance]))

getInstances node srvAddr srvPort = do

  client <- getConfdClient srvAddr srvPort

  reply <- query client ReqNodeInstances $ PlainQuery node

  return $

    case fmap (J.readJSON . confdReplyAnswer) reply of

      Just (J.Ok instances) -> BT.Ok instances

      Just (J.Error msg) -> BT.Bad msg

      Nothing -> BT.Bad "No answer from the Confd server"

-- | Try to get the reason trail for an instance. In case it is not possible,

-- log the failure and return an empty list instead.

getReasonTrail :: String -> IO ReasonTrail

getReasonTrail instanceName = do

  fileName <- getInstReasonFilename instanceName

  content <- try $ readFile fileName

  case content of

    Left e -> do

      logWarning $

        "Unable to open the reason trail for instance " ++ instanceName ++

        " expected at " ++ fileName ++ ": " ++ show (e :: IOException)

      return []

    Right trailString ->

      case J.decode trailString of

        J.Ok t -> return t

        J.Error msg -> do

          logWarning $ "Unable to parse the reason trail: " ++ msg

          return []

-- | Determine the value of the status field for the report of one instance

computeStatusField :: AdminState -> ActualState -> DCStatus

computeStatusField AdminDown actualState =

  if actualState `notElem` [ActualShutdown, ActualDying]

    then DCStatus DCSCBad "The instance is not stopped as it should be"

    else DCStatus DCSCOk ""

computeStatusField AdminUp ActualHung =

  DCStatus DCSCUnknown "Instance marked as running, but it appears to be hung"

computeStatusField AdminUp actualState =

  if actualState `notElem` [ActualRunning, ActualBlocked]

    then DCStatus DCSCBad "The instance is not running as it should be"

    else DCStatus DCSCOk ""

computeStatusField AdminOffline _ =

  -- FIXME: The "offline" status seems not to be used anywhere in the source

  -- code, but it is defined, so we have to consider it anyway here.

  DCStatus DCSCUnknown "The instance is marked as offline"

-- Builds the status of an instance using runtime information about the Xen

-- Domains, their uptime information and the static information provided by

-- the ConfD server.

buildStatus :: Map.Map String Domain -> Map.Map Int UptimeInfo -> Instance

  -> IO InstStatus

buildStatus domains uptimes inst = do

  let name = instName inst

      currDomain = Map.lookup name domains

      idNum = fmap domId currDomain

      currUInfo = idNum >>= (`Map.lookup` uptimes)

      uptime = fmap uInfoUptime currUInfo

      adminState = instAdminState inst

      actualState =

        if adminState == AdminDown && isNothing currDomain

          then ActualShutdown

          else case currDomain of

            (Just dom@(Domain _ _ _ _ (Just isHung))) ->

              if isHung

                then ActualHung

                else domState dom

            _ -> ActualUnknown

      status = computeStatusField adminState actualState

  trail <- getReasonTrail name

  return $

    InstStatus

      name

      (instUuid inst)

      adminState

      actualState

      uptime

      (instMtime inst)

      trail

      status

-- | Main function.

main :: Options -> [String] -> IO ()

main opts _ = do

  curNode <- getHostName

  let node = fromMaybe curNode $ optNode opts

  answer <- getInstances node (optConfdAddr opts) (optConfdPort opts)

  inst <- exitIfBad "Can't get instance info from ConfD" answer

  domains <- getInferredDomInfo

  uptimes <- getUptimeInfo

  let primaryInst =  fst inst

  iStatus <- mapM (buildStatus domains uptimes) primaryInst

  putStrLn $ J.encode iStatus