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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

  , instanceFields

  , instanceAliases

  ) 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 Text.Printf

import Ganeti.BasicTypes

import Ganeti.Common

import Ganeti.Config

import qualified Ganeti.Constants as C

import qualified Ganeti.ConstantUtils as C

import Ganeti.Errors

import Ganeti.JSON

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

import Ganeti.Utils (formatOrdinal)

-- | 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, _, _) <- aliasedFields]

-- | The instance aliases.

instanceAliases :: [(FieldName, FieldName)]

instanceAliases =

  [ ("vcpus", "be/vcpus")

  , ("be/memory", "be/maxmem")

  , ("sda_size", "disk.size/0")

  , ("sdb_size", "disk.size/1")

  , ("ip", "nic.ip/0")

  , ("mac", "nic.mac/0")

  , ("bridge", "nic.bridge/0")

  , ("nic_mode", "nic.mode/0")

  , ("nic_link", "nic.link/0")

  , ("nic_network", "nic.network/0")

  ]

-- | The aliased instance fields.

aliasedFields :: FieldList Instance Runtime

aliasedFields = aliasFields instanceAliases instanceFields

-- | The instance fields.

instanceFields :: FieldList Instance Runtime

instanceFields =

  -- Simple fields

  [ (FieldDefinition "admin_state" "InstanceState" QFTText

     "Desired state of instance",

     FieldSimple (rsNormal . adminStateToRaw . instAdminState), QffNormal)

  , (FieldDefinition "admin_up" "Autostart" QFTBool

     "Desired state of instance",

     FieldSimple (rsNormal . (== AdminUp) . instAdminState), QffNormal)

  , (FieldDefinition "disk_template" "Disk_template" QFTText

     "Instance disk template",

     FieldSimple (rsNormal . instDiskTemplate), QffNormal)

  , (FieldDefinition "disks_active" "DisksActive" QFTBool

     "Desired state of instance disks",

     FieldSimple (rsNormal . instDisksActive), 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)

  , (FieldDefinition "pnode" "Primary_node" QFTText

     "Primary node",

     FieldConfig getPrimaryNodeName, QffHostname)

  , (FieldDefinition "pnode.group" "PrimaryNodeGroup" QFTText

     "Primary node's group",

     FieldConfig getPrimaryNodeGroup, QffNormal)

  , (FieldDefinition "snodes" "Secondary_Nodes" QFTOther

     "Secondary nodes; usually this will just be one node",

     FieldConfig (getSecondaryNodeAttribute nodeName), QffNormal)

  , (FieldDefinition "snodes.group" "SecondaryNodesGroups" QFTOther

     "Node groups of secondary nodes",

     FieldConfig (getSecondaryNodeGroupAttribute groupName), QffNormal)

  , (FieldDefinition "snodes.group.uuid" "SecondaryNodesGroupsUUID" QFTOther

     "Node group UUIDs of secondary nodes",

     FieldConfig (getSecondaryNodeGroupAttribute groupUuid), QffNormal)

  ] ++

  -- Instance parameter fields, whole

  [ (FieldDefinition "hvparams" "HypervisorParameters" QFTOther

     "Hypervisor parameters (merged)",

     FieldConfig ((rsNormal .) . getFilledInstHvParams), QffNormal)

  , (FieldDefinition "beparams" "BackendParameters" QFTOther

     "Backend parameters (merged)",

     FieldConfig ((rsErrorNoData .) . getFilledInstBeParams), QffNormal)

  , (FieldDefinition "osparams" "OpSysParameters" QFTOther

     "Operating system parameters (merged)",

     FieldConfig ((rsNormal .) . getFilledInstOsParams), QffNormal)

  , (FieldDefinition "custom_hvparams" "CustomHypervisorParameters" QFTOther

     "Custom hypervisor parameters",

     FieldSimple (rsNormal . instHvparams), QffNormal)

  , (FieldDefinition "custom_beparams" "CustomBackendParameters" QFTOther

     "Custom backend parameters",

     FieldSimple (rsNormal . instBeparams), QffNormal)

  , (FieldDefinition "custom_osparams" "CustomOpSysParameters" QFTOther

     "Custom operating system parameters",

     FieldSimple (rsNormal . instOsparams), QffNormal)

  ] ++

  -- Instance parameter fields, generated

  map (buildBeParamField beParamGetter) allBeParamFields ++

  map (buildHvParamField hvParamGetter) (C.toList C.hvsParameters) ++

  -- Aggregate disk parameter fields

  [ (FieldDefinition "disk_usage" "DiskUsage" QFTUnit

     "Total disk space used by instance on each of its nodes; this is not the\

     \ disk size visible to the instance, but the usage on the node",

     FieldSimple (rsNormal . getDiskSizeRequirements), QffNormal)

  , (FieldDefinition "disk.count" "Disks" QFTNumber

     "Number of disks",

     FieldSimple (rsNormal . length . instDisks), QffNormal)

  , (FieldDefinition "disk.sizes" "Disk_sizes" QFTOther

     "List of disk sizes",

     FieldSimple (rsNormal . map diskSize . instDisks), QffNormal)

  , (FieldDefinition "disk.spindles" "Disk_spindles" QFTOther

     "List of disk spindles",

     FieldSimple (rsNormal . map (MaybeForJSON . diskSpindles) .

                  instDisks),

     QffNormal)

  , (FieldDefinition "disk.names" "Disk_names" QFTOther

     "List of disk names",

     FieldSimple (rsNormal . map (MaybeForJSON . diskName) .

                  instDisks),

     QffNormal)

  , (FieldDefinition "disk.uuids" "Disk_UUIDs" QFTOther

     "List of disk UUIDs",

     FieldSimple (rsNormal . map diskUuid . instDisks), QffNormal)

  ] ++

  -- Per-disk parameter fields

  instantiateIndexedFields C.maxDisks

  [ (fieldDefinitionCompleter "disk.size/%d" "Disk/%d" QFTUnit

     "Disk size of %s disk",

     getIndexedField instDisks diskSize, QffNormal)

  , (fieldDefinitionCompleter "disk.spindles/%d" "DiskSpindles/%d" QFTNumber

     "Spindles of %s disk",

     getIndexedOptionalField instDisks diskSpindles, QffNormal)

  , (fieldDefinitionCompleter "disk.name/%d" "DiskName/%d" QFTText

     "Name of %s disk",

     getIndexedOptionalField instDisks diskName, QffNormal)

  , (fieldDefinitionCompleter "disk.uuid/%d" "DiskUUID/%d" QFTText

     "UUID of %s disk",

     getIndexedField instDisks diskUuid, QffNormal)

  ] ++

  -- Aggregate nic parameter fields

  [ (FieldDefinition "nic.count" "NICs" QFTNumber

     "Number of network interfaces",

     FieldSimple (rsNormal . length . instNics), QffNormal)

  , (FieldDefinition "nic.macs" "NIC_MACs" QFTOther

     (nicAggDescPrefix ++ "MAC address"),

     FieldSimple (rsNormal . map nicMac . instNics), QffNormal)

  , (FieldDefinition "nic.ips" "NIC_IPs" QFTOther

     (nicAggDescPrefix ++ "IP address"),

     FieldSimple (rsNormal . map (MaybeForJSON . nicIp) . instNics),

     QffNormal)

  , (FieldDefinition "nic.names" "NIC_Names" QFTOther

     (nicAggDescPrefix ++ "name"),

     FieldSimple (rsNormal . map (MaybeForJSON . nicName) . instNics),

     QffNormal)

  , (FieldDefinition "nic.uuids" "NIC_UUIDs" QFTOther

     (nicAggDescPrefix ++ "UUID"),

     FieldSimple (rsNormal . map nicUuid . instNics), QffNormal)

  , (FieldDefinition "nic.modes" "NIC_modes" QFTOther

     (nicAggDescPrefix ++ "mode"),

     FieldConfig (\cfg -> rsNormal . map

       (nicpMode . fillNicParamsFromConfig cfg . nicNicparams)

       . instNics),

     QffNormal)

  , (FieldDefinition "nic.bridges" "NIC_bridges" QFTOther

     (nicAggDescPrefix ++ "bridge"),

     FieldConfig (\cfg -> rsNormal . map (MaybeForJSON . getNicBridge .

       fillNicParamsFromConfig cfg . nicNicparams) . instNics),

     QffNormal)

  , (FieldDefinition "nic.links" "NIC_links" QFTOther

     (nicAggDescPrefix ++ "link"),

     FieldConfig (\cfg -> rsNormal . map

       (nicpLink . fillNicParamsFromConfig cfg . nicNicparams)

       . instNics),

     QffNormal)

  , (FieldDefinition "nic.networks" "NIC_networks" QFTOther

     "List containing each interface's network",

     FieldSimple (rsNormal . map (MaybeForJSON . nicNetwork) . instNics),

     QffNormal)

  , (FieldDefinition "nic.networks.names" "NIC_networks_names" QFTOther

     "List containing the name of each interface's network",

     FieldConfig (\cfg -> rsNormal . map

       (\x -> MaybeForJSON (getNetworkName cfg <$> nicNetwork x))

       . instNics),

     QffNormal)

  ] ++

  -- Per-nic parameter fields

  instantiateIndexedFields C.maxNics

  [ (fieldDefinitionCompleter "nic.ip/%d" "NicIP/%d" QFTText

     ("IP address" ++ nicDescSuffix),

     getIndexedOptionalField instNics nicIp, QffNormal)

  , (fieldDefinitionCompleter "nic.uuid/%d" "NicUUID/%d" QFTText

     ("UUID address" ++ nicDescSuffix),

     getIndexedField instNics nicUuid, QffNormal)

  , (fieldDefinitionCompleter "nic.mac/%d" "NicMAC/%d" QFTText

     ("MAC address" ++ nicDescSuffix),

     getIndexedField instNics nicMac, QffNormal)

  , (fieldDefinitionCompleter "nic.name/%d" "NicName/%d" QFTText

     ("Name address" ++ nicDescSuffix),

     getIndexedOptionalField instNics nicName, QffNormal)

  , (fieldDefinitionCompleter "nic.network/%d" "NicNetwork/%d" QFTText

     ("Network" ++ nicDescSuffix),

     getIndexedOptionalField instNics nicNetwork, QffNormal)

  , (fieldDefinitionCompleter "nic.mode/%d" "NicMode/%d" QFTText

     ("Mode" ++ nicDescSuffix),

     getIndexedNicField nicpMode, QffNormal)

  , (fieldDefinitionCompleter "nic.link/%d" "NicLink/%d" QFTText

     ("Link" ++ nicDescSuffix),

     getIndexedNicField nicpLink, QffNormal)

  , (fieldDefinitionCompleter "nic.network.name/%d" "NicNetworkName/%d" QFTText

     ("Network name" ++ nicDescSuffix),

     getIndexedNicNetworkNameField, QffNormal)

  , (fieldDefinitionCompleter "nic.bridge/%d" "NicBridge/%d" QFTText

     ("Bridge" ++ nicDescSuffix),

     getOptionalIndexedNicField getNicBridge, 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

-- * Helper functions for node property retrieval

-- | Constant suffix of network interface field descriptions.

nicDescSuffix ::String

nicDescSuffix = " of %s network interface"

-- | Almost-constant suffix of aggregate network interface field descriptions.

nicAggDescPrefix ::String

nicAggDescPrefix = "List containing each network interface's "

-- | Given a network name id, returns the network's name.

getNetworkName :: ConfigData -> String -> NonEmptyString

getNetworkName cfg = networkName . (Map.!) (fromContainer $ configNetworks cfg)

-- | Gets the bridge of a NIC.

getNicBridge :: FilledNicParams -> Maybe String

getNicBridge nicParams

  | nicpMode nicParams == NMBridged = Just $ nicpLink nicParams

  | otherwise                       = Nothing

-- | Fill partial NIC params by using the defaults from the configuration.

fillNicParamsFromConfig :: ConfigData -> PartialNicParams -> FilledNicParams

fillNicParamsFromConfig cfg = fillNicParams (getDefaultNicParams cfg)

-- | Retrieves the default network interface parameters.

getDefaultNicParams :: ConfigData -> FilledNicParams

getDefaultNicParams cfg =

  (Map.!) (fromContainer . clusterNicparams . configCluster $ cfg) C.ppDefault

-- | Returns a field that retrieves a given NIC's network name.

getIndexedNicNetworkNameField :: Int -> FieldGetter Instance Runtime

getIndexedNicNetworkNameField index =

  FieldConfig (\cfg inst -> rsMaybeUnavail $ do

    nicObj <- maybeAt index $ instNics inst

    nicNetworkId <- nicNetwork nicObj

    return $ getNetworkName cfg nicNetworkId)

-- | Gets a fillable NIC field.

getIndexedNicField :: (J.JSON a)

                   => (FilledNicParams -> a)

                   -> Int

                   -> FieldGetter Instance Runtime

getIndexedNicField getter =

  getOptionalIndexedNicField (\x -> Just . getter $ x)

-- | Gets an optional fillable NIC field.

getOptionalIndexedNicField :: (J.JSON a)

                           => (FilledNicParams -> Maybe a)

                           -> Int

                           -> FieldGetter Instance Runtime

getOptionalIndexedNicField =

  getIndexedFieldWithDefault

    (map nicNicparams . instNics) (\x _ -> getDefaultNicParams x) fillNicParams

-- | Creates a function which produces a 'FieldGetter' when fed an index. Works

-- for fields that should be filled out through the use of a default.

getIndexedFieldWithDefault :: (J.JSON c)

  => (Instance -> [a])             -- ^ Extracts a list of incomplete objects

  -> (ConfigData -> Instance -> b) -- ^ Extracts the default object

  -> (b -> a -> b)                 -- ^ Fills the default object

  -> (b -> Maybe c)                -- ^ Extracts an obj property

  -> Int                           -- ^ Index in list to use

  -> FieldGetter Instance Runtime  -- ^ Result

getIndexedFieldWithDefault

  listGetter defaultGetter fillFn propertyGetter index =

  FieldConfig (\cfg inst -> rsMaybeUnavail $ do

                              incompleteObj <- maybeAt index $ listGetter inst

                              let defaultObj = defaultGetter cfg inst

                                  completeObj = fillFn defaultObj incompleteObj

                              propertyGetter completeObj)

-- | Creates a function which produces a 'FieldGetter' when fed an index. Works

-- for fields that may not return a value, expressed through the Maybe monad.

getIndexedOptionalField :: (J.JSON b)

                        => (Instance -> [a]) -- ^ Extracts a list of objects

                        -> (a -> Maybe b)    -- ^ Possibly gets a property

                                             -- from an object

                        -> Int               -- ^ Index in list to use

                        -> FieldGetter Instance Runtime -- ^ Result

getIndexedOptionalField extractor optPropertyGetter index =

  FieldSimple(\inst -> rsMaybeUnavail $ do

                         obj <- maybeAt index $ extractor inst

                         optPropertyGetter obj)

-- | Creates a function which produces a 'FieldGetter' when fed an index.

-- Works only for fields that surely return a value.

getIndexedField :: (J.JSON b)

                => (Instance -> [a]) -- ^ Extracts a list of objects

                -> (a -> b)          -- ^ Gets a property from an object

                -> Int               -- ^ Index in list to use

                -> FieldGetter Instance Runtime -- ^ Result

getIndexedField extractor propertyGetter index =

  let optPropertyGetter = Just . propertyGetter

  in getIndexedOptionalField extractor optPropertyGetter index

-- | Retrieves a value from an array at an index, using the Maybe monad to

-- indicate failure.

maybeAt :: Int -> [a] -> Maybe a

maybeAt index list

  | index >= length list = Nothing

  | otherwise            = Just $ list !! index

-- | Primed with format strings for everything but the type, it consumes two

-- values and uses them to complete the FieldDefinition.

-- Warning: a bit unsafe as it uses printf. Handle with care.

fieldDefinitionCompleter :: (PrintfArg t1) => (PrintfArg t2)

                         => FieldName

                         -> FieldTitle

                         -> FieldType

                         -> FieldDoc

                         -> t1

                         -> t2

                         -> FieldDefinition

fieldDefinitionCompleter fName fTitle fType fDoc firstVal secondVal =

  FieldDefinition (printf fName firstVal)

                  (printf fTitle firstVal)

                  fType

                  (printf fDoc secondVal)

-- | Given an incomplete field definition and values that can complete it,

-- return a fully functional FieldData. Cannot work for all cases, should be

-- extended as necessary.

fillIncompleteFields :: (t1 -> t2 -> FieldDefinition,

                         t1 -> FieldGetter a b,

                         QffMode)

                     -> t1

                     -> t2

                     -> FieldData a b

fillIncompleteFields (iDef, iGet, mode) firstVal secondVal =

  (iDef firstVal secondVal, iGet firstVal, mode)

-- | Given indexed fields that describe lists, complete / instantiate them for

-- a given list size.

instantiateIndexedFields :: (Show t1, Integral t1)

                         => Int            -- ^ The size of the list

                         -> [(t1 -> String -> FieldDefinition,

                              t1 -> FieldGetter a b,

                              QffMode)]    -- ^ The indexed fields

                         -> FieldList a b  -- ^ A list of complete fields

instantiateIndexedFields listSize fields = do

  index <- take listSize [0..]

  field <- fields

  return . fillIncompleteFields field index . formatOrdinal $ index + 1

-- * Various helper functions for property retrieval

-- | Helper function for primary node retrieval

getPrimaryNode :: ConfigData -> Instance -> ErrorResult Node

getPrimaryNode cfg = getInstPrimaryNode cfg . instName

-- | Get primary node hostname

getPrimaryNodeName :: ConfigData -> Instance -> ResultEntry

getPrimaryNodeName cfg inst =

  rsErrorNoData $ nodeName <$> getPrimaryNode cfg inst

-- | Get primary node hostname

getPrimaryNodeGroup :: ConfigData -> Instance -> ResultEntry

getPrimaryNodeGroup cfg inst =

  rsErrorNoData $ (J.showJSON . groupName) <$>

    (getPrimaryNode cfg inst >>=

    maybeToError "Configuration missing" . getGroupOfNode cfg)

-- | Get secondary nodes - the configuration objects themselves

getSecondaryNodes :: ConfigData -> Instance -> ErrorResult [Node]

getSecondaryNodes cfg inst = do

  pNode <- getPrimaryNode cfg inst

  allNodes <- getInstAllNodes cfg $ instName inst

  return $ delete pNode allNodes

-- | Get attributes of the secondary nodes

getSecondaryNodeAttribute :: (J.JSON a)

                          => (Node -> a)

                          -> ConfigData

                          -> Instance

                          -> ResultEntry

getSecondaryNodeAttribute getter cfg inst =

  rsErrorNoData $ map (J.showJSON . getter) <$> getSecondaryNodes cfg inst

-- | Get secondary node groups

getSecondaryNodeGroups :: ConfigData -> Instance -> ErrorResult [NodeGroup]

getSecondaryNodeGroups cfg inst = do

  sNodes <- getSecondaryNodes cfg inst

  return . catMaybes $ map (getGroupOfNode cfg) sNodes

-- | Get attributes of secondary node groups

getSecondaryNodeGroupAttribute :: (J.JSON a)

                               => (NodeGroup -> a)

                               -> ConfigData

                               -> Instance

                               -> ResultEntry

getSecondaryNodeGroupAttribute getter cfg inst =

  rsErrorNoData $ map (J.showJSON . getter) <$> getSecondaryNodeGroups cfg inst

-- | Beparam getter builder: given a field, it returns a FieldConfig

-- getter, that is a function that takes the config and the object and

-- returns the Beparam field specified when the getter was built.

beParamGetter :: String       -- ^ The field we are building the getter for

              -> ConfigData   -- ^ The configuration object

              -> Instance     -- ^ The instance configuration object

              -> ResultEntry  -- ^ The result

beParamGetter field config inst =

  case getFilledInstBeParams config inst of

    Ok beParams -> dictFieldGetter field $ Just beParams

    Bad       _ -> rsNoData

-- | Hvparam getter builder: given a field, it returns a FieldConfig

-- getter, that is a function that takes the config and the object and

-- returns the Hvparam field specified when the getter was built.

hvParamGetter :: String -- ^ The field we're building the getter for

              -> ConfigData -> Instance -> ResultEntry

hvParamGetter field cfg inst =

  rsMaybeUnavail . Map.lookup field . fromContainer $

                                        getFilledInstHvParams cfg inst

-- * 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 pNodeResult = getNode cfg $ instPrimaryNode inst

  in case pNodeResult of

     Ok pNode -> nodeOffline pNode

     Bad    _ -> error "Programmer error - result assumed to be OK is Bad!"

-- | 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        -- ^ Static instance configuration

                        -> InstanceStatus  -- ^ Result

determineInstanceStatus cfg res inst

  | isPrimaryOffline cfg inst = NodeOffline

  | otherwise = case res of

                  Left _                -> NodeDown

                  Right (Just liveData) -> liveInstanceStatus liveData inst

                  Right Nothing         -> deadInstanceStatus inst

-- | Extracts the instance status, retrieving it using the functions above and

-- transforming it into a 'ResultEntry'.

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

statusExtract cfg res inst =

  rsNormal . J.showJSON . instanceStatusToRaw $

    determineInstanceStatus cfg res inst

-- | Extracts the operational status of the instance.

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

-- | 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 . justOk $

                             map (getNode cfg . instPrimaryNode) instances

          good_nodes = nodesWithValidConfig cfg instance_nodes

      rpcres <- executeRpcCall good_nodes $ RpcCallAllInstancesInfo [hvSpec]

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