src/Ganeti/Query/Common.hs

{-| Implementation of the Ganeti Query2 common objects.

 -}

{-

Copyright (C) 2012, 2013 Google Inc.
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

1. Redistributions of source code must retain the above copyright notice,
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
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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.Query.Common
  ( rsNoData
  , rsUnavail
  , rsNormal
  , rsMaybeNoData
  , rsMaybeUnavail
  , rsUnknown
  , missingRuntime
  , rpcErrorToStatus
  , timeStampFields
  , uuidFields
  , serialFields
  , tagsFields
  , dictFieldGetter
  , buildNdParamField
  ) where

import qualified Data.Map as Map
import Data.Maybe (fromMaybe)
import Text.JSON (JSON, showJSON)

import qualified Ganeti.Constants as C
import Ganeti.Config
import Ganeti.Objects
import Ganeti.Rpc
import Ganeti.Query.Language
import Ganeti.Query.Types
import Ganeti.Types

-- * Generic functions

-- | Conversion from 'VType' to 'FieldType'.
vTypeToQFT :: VType -> FieldType
vTypeToQFT VTypeString      = QFTOther
vTypeToQFT VTypeMaybeString = QFTOther
vTypeToQFT VTypeBool        = QFTBool
vTypeToQFT VTypeSize        = QFTUnit
vTypeToQFT VTypeInt         = QFTNumber

-- * Result helpers

-- | Helper for a result with no data.
rsNoData :: ResultEntry
rsNoData = ResultEntry RSNoData Nothing

-- | Helper for result for an entity which supports no such field.
rsUnavail :: ResultEntry
rsUnavail = ResultEntry RSUnavail Nothing

-- | Helper to declare a normal result.
rsNormal :: (JSON a) => a -> ResultEntry
rsNormal a = ResultEntry RSNormal $ Just (showJSON a)

-- | Helper to declare a result from a 'Maybe' (the item might be
-- missing, in which case we return no data). Note that there's some
-- ambiguity here: in some cases, we mean 'RSNoData', but in other
-- 'RSUnavail'; this is easy to solve in simple cases, but not in
-- nested dicts. If you want to return 'RSUnavail' in case of 'Nothing'
-- use the function 'rsMaybeUnavail'.
rsMaybeNoData :: (JSON a) => Maybe a -> ResultEntry
rsMaybeNoData = maybe rsNoData rsNormal

-- | Helper to declare a result from a 'Maybe'. This version returns
-- a 'RSUnavail' in case of 'Nothing'. It should be used for optional
-- fields that are not set. For cases where 'Nothing' means that there
-- was an error, consider using 'rsMaybe' instead.
rsMaybeUnavail :: (JSON a) => Maybe a -> ResultEntry
rsMaybeUnavail = maybe rsUnavail rsNormal

-- | Helper for unknown field result.
rsUnknown :: ResultEntry
rsUnknown = ResultEntry RSUnknown Nothing

-- | Helper for a missing runtime parameter.
missingRuntime :: FieldGetter a b
missingRuntime = FieldRuntime (\_ _ -> ResultEntry RSNoData Nothing)

-- * Error conversion

-- | Convert RpcError to ResultStatus
rpcErrorToStatus :: RpcError -> ResultStatus
rpcErrorToStatus OfflineNodeError = RSOffline
rpcErrorToStatus _ = RSNoData

-- * Common fields

-- | The list of timestamp fields.
timeStampFields :: (TimeStampObject a) => FieldList a b
timeStampFields =
  [ (FieldDefinition "ctime" "CTime" QFTTimestamp "Creation timestamp",
     FieldSimple (rsNormal . cTimeOf), QffNormal)
  , (FieldDefinition "mtime" "MTime" QFTTimestamp "Modification timestamp",
     FieldSimple (rsNormal . mTimeOf), QffNormal)
  ]

-- | The list of UUID fields.
uuidFields :: (UuidObject a) => String -> FieldList a b
uuidFields name =
  [ (FieldDefinition "uuid" "UUID" QFTText  (name ++ " UUID"),
     FieldSimple (rsNormal . uuidOf), QffNormal) ]

-- | The list of serial number fields.
serialFields :: (SerialNoObject a) => String -> FieldList a b
serialFields name =
  [ (FieldDefinition "serial_no" "SerialNo" QFTNumber
     (name ++ " object serial number, incremented on each modification"),
     FieldSimple (rsNormal . serialOf), QffNormal) ]

-- | The list of tag fields.
tagsFields :: (TagsObject a) => FieldList a b
tagsFields =
  [ (FieldDefinition "tags" "Tags" QFTOther "Tags",
     FieldSimple (rsNormal . tagsOf), QffNormal) ]

-- * Generic parameter functions

-- | Returns a field from a (possibly missing) 'DictObject'. This is
-- used by parameter dictionaries, usually. Note that we have two
-- levels of maybe: the top level dict might be missing, or one key in
-- the dictionary might be.
dictFieldGetter :: (DictObject a) => String -> Maybe a -> ResultEntry
dictFieldGetter k = maybe rsNoData (rsMaybeNoData . lookup k . toDict)

-- | Ndparams optimised lookup map.
ndParamTypes :: Map.Map String FieldType
ndParamTypes = Map.map vTypeToQFT C.ndsParameterTypes

-- | Ndparams title map.
ndParamTitles :: Map.Map String FieldTitle
ndParamTitles = C.ndsParameterTitles

-- | Ndparam getter builder: given a field, it returns a FieldConfig
-- getter, that is a function that takes the config and the object and
-- returns the Ndparam field specified when the getter was built.
ndParamGetter :: (NdParamObject a) =>
                 String -- ^ The field we're building the getter for
              -> ConfigData -> a -> ResultEntry
ndParamGetter field config =
  dictFieldGetter field . getNdParamsOf config

-- | Builds the ndparam fields for an object.
buildNdParamField :: (NdParamObject a) => String -> FieldData a b
buildNdParamField field =
  let full_name = "ndp/" ++ field
      title = fromMaybe field $ field `Map.lookup` ndParamTitles
      qft = fromMaybe QFTOther $ field `Map.lookup` ndParamTypes
      desc = "The \"" ++ field ++ "\" node parameter"
  in (FieldDefinition full_name title qft desc,
      FieldConfig (ndParamGetter field), QffNormal)