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{-| Implementation of the Ganeti Query2 instance queries.

-}

{-

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.Query.Instance

  ( Runtime

  , fieldsMap

  , collectLiveData

  ) where

import Control.Applicative

import Data.List

import Data.Maybe

import Data.Monoid

import qualified Data.Map as Map

import qualified Text.JSON as J

import Ganeti.BasicTypes

import Ganeti.Common

import Ganeti.Config

import Ganeti.Objects

import Ganeti.Query.Common

import Ganeti.Query.Language

import Ganeti.Query.Types

import Ganeti.Rpc

import Ganeti.Storage.Utils

import Ganeti.Types

-- | The LiveInfo structure packs additional information beside the

-- 'InstanceInfo'. We also need to know whether the instance information was

-- found on the primary node, and encode this as a Bool.

type LiveInfo = (InstanceInfo, Bool)

-- | Runtime possibly containing the 'LiveInfo'. See the genericQuery function

-- in the Query.hs file for an explanation of the terms used.

type Runtime = Either RpcError (Maybe LiveInfo)

-- | The instance fields map.

fieldsMap :: FieldMap Instance Runtime

fieldsMap = Map.fromList [(fdefName f, v) | v@(f, _, _) <- instanceFields]

-- | The instance fields

instanceFields :: FieldList Instance Runtime

instanceFields =

  -- Simple fields

  [ (FieldDefinition "disk_template" "Disk_template" QFTText

     "Instance disk template",

     FieldSimple (rsNormal . instDiskTemplate), QffNormal)

  , (FieldDefinition "name" "Instance" QFTText

     "Instance name",

     FieldSimple (rsNormal . instName), QffHostname)

  , (FieldDefinition "hypervisor" "Hypervisor" QFTText

     "Hypervisor name",

     FieldSimple (rsNormal . instHypervisor), QffNormal)

  , (FieldDefinition "network_port" "Network_port" QFTOther

     "Instance network port if available (e.g. for VNC console)",

     FieldSimple (rsMaybeUnavail . instNetworkPort), QffNormal)

  , (FieldDefinition "os" "OS" QFTText

     "Operating system",

     FieldSimple (rsNormal . instOs), QffNormal)

  ] ++

  -- Live fields using special getters

  [ (FieldDefinition "status" "Status" QFTText

     statusDocText,

     FieldConfigRuntime statusExtract, QffNormal)

  , (FieldDefinition "oper_state" "Running" QFTBool

     "Actual state of instance",

     FieldRuntime operStatusExtract, QffNormal)

  ] ++

  -- Simple live fields

  map instanceLiveFieldBuilder instanceLiveFieldsDefs ++

  -- Generated fields

  serialFields "Instance" ++

  uuidFields "Instance" ++

  tagsFields

-- * Live fields functionality

-- | List of node live fields.

instanceLiveFieldsDefs :: [(FieldName, FieldTitle, FieldType, String, FieldDoc)]

instanceLiveFieldsDefs =

  [ ("oper_ram", "Memory", QFTUnit, "oper_ram",

     "Actual memory usage as seen by hypervisor")

  , ("oper_vcpus", "VCPUs", QFTNumber, "oper_vcpus",

     "Actual number of VCPUs as seen by hypervisor")

  ]

-- | Map each name to a function that extracts that value from the RPC result.

instanceLiveFieldExtract :: FieldName -> InstanceInfo -> Instance -> J.JSValue

instanceLiveFieldExtract "oper_ram"   info _ = J.showJSON $ instInfoMemory info

instanceLiveFieldExtract "oper_vcpus" info _ = J.showJSON $ instInfoVcpus info

instanceLiveFieldExtract n _ _ = J.showJSON $

  "The field " ++ n ++ " is not an expected or extractable live field!"

-- | Helper for extracting field from RPC result.

instanceLiveRpcCall :: FieldName -> Runtime -> Instance -> ResultEntry

instanceLiveRpcCall fname (Right (Just (res, _))) inst =

  case instanceLiveFieldExtract fname res inst of

    J.JSNull -> rsNoData

    x        -> rsNormal x

instanceLiveRpcCall _ (Right Nothing) _ = rsUnavail

instanceLiveRpcCall _ (Left err) _ =

  ResultEntry (rpcErrorToStatus err) Nothing

-- | Builder for node live fields.

instanceLiveFieldBuilder :: (FieldName, FieldTitle, FieldType, String, FieldDoc)

                     -> FieldData Instance Runtime

instanceLiveFieldBuilder (fname, ftitle, ftype, _, fdoc) =

  ( FieldDefinition fname ftitle ftype fdoc

  , FieldRuntime $ instanceLiveRpcCall fname

  , QffNormal)

-- Functionality related to status and operational status extraction

-- | The documentation text for the instance status field

statusDocText :: String

statusDocText =

  let si = show . instanceStatusToRaw :: InstanceStatus -> String

  in "Instance status; " ++

     si Running ++

     " if instance is set to be running and actually is, " ++

     si StatusDown ++

     " if instance is stopped and is not running, " ++

     si WrongNode ++

     " if instance running, but not on its designated primary node, " ++

     si ErrorUp ++

     " if instance should be stopped, but is actually running, " ++

     si ErrorDown ++

     " if instance should run, but doesn't, " ++

     si NodeDown ++

     " if instance's primary node is down, " ++

     si NodeOffline ++

     " if instance's primary node is marked offline, " ++

     si StatusOffline ++

     " if instance is offline and does not use dynamic resources"

-- | Checks if the primary node of an instance is offline

isPrimaryOffline :: ConfigData -> Instance -> Bool

isPrimaryOffline cfg inst =

  let pNode = optimisticUnwrapper . getNode cfg $ instPrimaryNode inst

  in nodeOffline pNode

-- | Determines the status of a live instance

liveInstanceStatus :: LiveInfo -> Instance -> InstanceStatus

liveInstanceStatus (_, foundOnPrimary) inst

  | not foundOnPrimary    = WrongNode

  | adminState == AdminUp = Running

  | otherwise             = ErrorUp

  where adminState = instAdminState inst

-- | Determines the status of a dead instance.

deadInstanceStatus :: Instance -> InstanceStatus

deadInstanceStatus inst =

  case instAdminState inst of

    AdminUp      -> ErrorDown

    AdminDown    -> StatusDown

    AdminOffline -> StatusOffline

-- | Determines the status of the instance, depending on whether it is possible

-- | to communicate with its primary node, on which node it is, and its

-- | configuration.

determineInstanceStatus :: ConfigData -- ^ The configuration data

                        -> Runtime    -- ^ All the data from the live call

                        -> Instance   -- ^ The static instance configuration

                        -> InstanceStatus -- ^ Result

determineInstanceStatus cfg res inst =

  if isPrimaryOffline cfg inst

    then NodeOffline

    else case res of

      Left _                -> NodeDown

      Right (Just liveData) -> liveInstanceStatus liveData inst

      Right Nothing         -> deadInstanceStatus inst

-- | Extracts the status, doing necessary transformations but once

statusExtract :: ConfigData -> Runtime -> Instance -> ResultEntry

statusExtract cfg res inst =

  rsNormal . J.showJSON . instanceStatusToRaw $

    determineInstanceStatus cfg res inst

-- | Extracts the operational status

operStatusExtract :: Runtime -> Instance -> ResultEntry

operStatusExtract res _ =

  rsMaybeNoData $ J.showJSON <$> case res of

    Left _  -> Nothing

    Right x -> Just $ isJust x

-- Helper functions extracting information as necessary for the generic query

-- interfaces

-- | A function removing the GenericResult wrapper from assuredly OK values

optimisticUnwrapper :: GenericResult a b -> b

optimisticUnwrapper (Ok x) = x

optimisticUnwrapper (Bad _) = error "Programmer error: assumptions are wrong!"

-- | Simple filter of OK results only

okNodesOnly :: [GenericResult a Node] -> [Node]

okNodesOnly = map optimisticUnwrapper . filter isOk

-- | Finds information about the instance in the info delivered by a node

findInstanceInfo :: Instance

                 -> ERpcError RpcResultAllInstancesInfo

                 -> Maybe InstanceInfo

findInstanceInfo inst nodeResponse =

  case nodeResponse of

    Left  _err    -> Nothing

    Right allInfo ->

      let instances = rpcResAllInstInfoInstances allInfo

          maybeMatch = pickPairUnique (instName inst) instances

      in snd <$> maybeMatch

-- | Finds the node information ('RPCResultError') or the instance information

-- (Maybe 'LiveInfo').

extractLiveInfo :: [(Node, ERpcError RpcResultAllInstancesInfo)]

                -> Instance

                -> Runtime

extractLiveInfo nodeResultList inst =

  let uuidResultList = [(nodeUuid x, y) | (x, y) <- nodeResultList]

      pNodeUuid = instPrimaryNode inst

      maybeRPCError = getNodeStatus uuidResultList pNodeUuid

  in case maybeRPCError of

       Just err -> Left err

       Nothing  -> Right $ getInstanceStatus uuidResultList pNodeUuid inst

-- | Tries to find out if the node given by the uuid is bad - unreachable or

-- returning errors, does not mather for the purpose of this call.

getNodeStatus :: [(String, ERpcError RpcResultAllInstancesInfo)]

              -> String

              -> Maybe RpcError

getNodeStatus uuidList uuid =

  case snd <$> pickPairUnique uuid uuidList of

    Just (Left err) -> Just err

    Just (Right _)  -> Nothing

    Nothing         -> Just . RpcResultError $

                         "Primary node response not present"

-- | Retrieves the instance information if it is present anywhere in the all

-- instances RPC result. Notes if it originates from the primary node.

-- All nodes are represented as UUID's for ease of use.

getInstanceStatus :: [(String, ERpcError RpcResultAllInstancesInfo)]

                  -> String

                  -> Instance

                  -> Maybe LiveInfo

getInstanceStatus uuidList pNodeUuid inst =

  let primarySearchResult =

        snd <$> pickPairUnique pNodeUuid uuidList >>= findInstanceInfo inst

  in case primarySearchResult of

       Just instInfo -> Just (instInfo, True)

       Nothing       ->

         let allSearchResult =

               getFirst . mconcat $ map

               (First . findInstanceInfo inst . snd) uuidList

         in case allSearchResult of

              Just liveInfo -> Just (liveInfo, False)

              Nothing       -> Nothing

-- | Collect live data from RPC query if enabled.

collectLiveData :: Bool -> ConfigData -> [Instance] -> IO [(Instance, Runtime)]

collectLiveData liveDataEnabled cfg instances

  | not liveDataEnabled = return . zip instances . repeat . Left .

                            RpcResultError $ "Live data disabled"

  | otherwise = do

      let hvSpec = getDefaultHypervisorSpec cfg

          instance_nodes = nub . okNodesOnly $

                             map (getNode cfg . instPrimaryNode) instances

          good_nodes = nodesWithValidConfig cfg instance_nodes

      rpcres <- executeRpcCall good_nodes $ RpcCallAllInstancesInfo [hvSpec]

      return . zip instances . map (extractLiveInfo rpcres) $ instances