Synnefo » snf-ganeti

{-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies,

  BangPatterns, TemplateHaskell #-}

{-| Implementation of the RPC client.

-}

{-

Copyright (C) 2012, 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.Rpc

  ( RpcCall

  , Rpc

  , RpcError(..)

  , ERpcError

  , explainRpcError

  , executeRpcCall

  , rpcCallName

  , rpcCallTimeout

  , rpcCallData

  , rpcCallAcceptOffline

  , rpcResultFill

  , InstanceInfo(..)

  , RpcCallInstanceInfo(..)

  , RpcResultInstanceInfo(..)

  , RpcCallAllInstancesInfo(..)

  , RpcResultAllInstancesInfo(..)

  , RpcCallInstanceList(..)

  , RpcResultInstanceList(..)

  , HvInfo(..)

  , VgInfo(..)

  , RpcCallNodeInfo(..)

  , RpcResultNodeInfo(..)

  , RpcCallVersion(..)

  , RpcResultVersion(..)

  , StorageField(..)

  , RpcCallStorageList(..)

  , RpcResultStorageList(..)

  , RpcCallTestDelay(..)

  , RpcResultTestDelay(..)

  , rpcTimeoutFromRaw -- FIXME: Not used anywhere

  ) where

import Control.Arrow (second)

import qualified Data.Map as Map

import Data.Maybe (fromMaybe)

import qualified Text.JSON as J

import Text.JSON.Pretty (pp_value)

import Network.Curl

import qualified Ganeti.Path as P

import qualified Ganeti.Constants as C

import Ganeti.Objects

import Ganeti.THH

import Ganeti.Types

import Ganeti.Compat

-- * Base RPC functionality and types

-- | The curl options used for RPC.

curlOpts :: [CurlOption]

curlOpts = [ CurlFollowLocation False

           , CurlSSLVerifyHost 0

           , CurlSSLVerifyPeer True

           , CurlSSLCertType "PEM"

           , CurlSSLKeyType "PEM"

           , CurlConnectTimeout (fromIntegral C.rpcConnectTimeout)

           ]

-- | Data type for RPC error reporting.

data RpcError

  = CurlLayerError Node String

  | JsonDecodeError String

  | RpcResultError String

  | OfflineNodeError Node

  deriving (Show, Eq)

-- | Provide explanation to RPC errors.

explainRpcError :: RpcError -> String

explainRpcError (CurlLayerError node code) =

    "Curl error for " ++ nodeName node ++ ", " ++ code

explainRpcError (JsonDecodeError msg) =

    "Error while decoding JSON from HTTP response: " ++ msg

explainRpcError (RpcResultError msg) =

    "Error reponse received from RPC server: " ++ msg

explainRpcError (OfflineNodeError node) =

    "Node " ++ nodeName node ++ " is marked as offline"

type ERpcError = Either RpcError

-- | Basic timeouts for RPC calls.

$(declareIADT "RpcTimeout"

  [ ( "Urgent",    'C.rpcTmoUrgent )

  , ( "Fast",      'C.rpcTmoFast )

  , ( "Normal",    'C.rpcTmoNormal )

  , ( "Slow",      'C.rpcTmoSlow )

  , ( "FourHours", 'C.rpcTmo4hrs )

  , ( "OneDay",    'C.rpcTmo1day )

  ])

-- | A generic class for RPC calls.

class (J.JSON a) => RpcCall a where

  -- | Give the (Python) name of the procedure.

  rpcCallName :: a -> String

  -- | Calculate the timeout value for the call execution.

  rpcCallTimeout :: a -> Int

  -- | Prepare arguments of the call to be send as POST.

  rpcCallData :: Node -> a -> String

  -- | Whether we accept offline nodes when making a call.

  rpcCallAcceptOffline :: a -> Bool

-- | Generic class that ensures matching RPC call with its respective

-- result.

class (RpcCall a, J.JSON b) => Rpc a b  | a -> b, b -> a where

  -- | Create a result based on the received HTTP response.

  rpcResultFill :: a -> J.JSValue -> ERpcError b

-- | Http Request definition.

data HttpClientRequest = HttpClientRequest

  { requestUrl  :: String       -- ^ The actual URL for the node endpoint

  , requestData :: String       -- ^ The arguments for the call

  , requestOpts :: [CurlOption] -- ^ The various curl options

  }

-- | Execute the request and return the result as a plain String. When

-- curl reports an error, we propagate it.

executeHttpRequest :: Node -> ERpcError HttpClientRequest

                   -> IO (ERpcError String)

executeHttpRequest _ (Left rpc_err) = return $ Left rpc_err

executeHttpRequest node (Right request) = do

  let reqOpts = CurlPostFields [requestData request]:requestOpts request

      url = requestUrl request

  -- FIXME: This is very similar to getUrl in Htools/Rapi.hs

  (code, !body) <- curlGetString url $ curlOpts ++ reqOpts

  return $ case code of

             CurlOK -> Right body

             _ -> Left $ CurlLayerError node (show code)

-- | Prepare url for the HTTP request.

prepareUrl :: (RpcCall a) => Node -> a -> String

prepareUrl node call =

  let node_ip = nodePrimaryIp node

      port = snd C.daemonsPortsGanetiNoded

      path_prefix = "https://" ++ node_ip ++ ":" ++ show port

  in path_prefix ++ "/" ++ rpcCallName call

-- | Create HTTP request for a given node provided it is online,

-- otherwise create empty response.

prepareHttpRequest :: (RpcCall a) => [CurlOption] -> Node -> a

                   -> ERpcError HttpClientRequest

prepareHttpRequest opts node call

  | rpcCallAcceptOffline call || not (nodeOffline node) =

      Right HttpClientRequest { requestUrl  = prepareUrl node call

                              , requestData = rpcCallData node call

                              , requestOpts = opts ++ curlOpts

                              }

  | otherwise = Left $ OfflineNodeError node

-- | Parse a result based on the received HTTP response.

parseHttpResponse :: (Rpc a b) => a -> ERpcError String -> ERpcError b

parseHttpResponse _ (Left err) = Left err

parseHttpResponse call (Right res) =

  case J.decode res of

    J.Error val -> Left $ JsonDecodeError val

    J.Ok (True, res'') -> rpcResultFill call res''

    J.Ok (False, jerr) -> case jerr of

       J.JSString msg -> Left $ RpcResultError (J.fromJSString msg)

       _ -> Left . JsonDecodeError $ show (pp_value jerr)

-- | Execute RPC call for a sigle node.

executeSingleRpcCall :: (Rpc a b) =>

                        [CurlOption] -> Node -> a -> IO (Node, ERpcError b)

executeSingleRpcCall opts node call = do

  let request = prepareHttpRequest opts node call

  response <- executeHttpRequest node request

  let result = parseHttpResponse call response

  return (node, result)

-- | Execute RPC call for many nodes in parallel.

executeRpcCall :: (Rpc a b) => [Node] -> a -> IO [(Node, ERpcError b)]

executeRpcCall nodes call = do

  cert_file <- P.nodedCertFile

  let opts = [ CurlTimeout (fromIntegral $ rpcCallTimeout call)

             , CurlSSLCert cert_file

             , CurlSSLKey cert_file

             , CurlCAInfo cert_file

             ]

  sequence $ parMap rwhnf (\n -> executeSingleRpcCall opts n call) nodes

-- | Helper function that is used to read dictionaries of values.

sanitizeDictResults :: [(String, J.Result a)] -> ERpcError [(String, a)]

sanitizeDictResults =

  foldr sanitize1 (Right [])

  where

    sanitize1 _ (Left e) = Left e

    sanitize1 (_, J.Error e) _ = Left $ JsonDecodeError e

    sanitize1 (name, J.Ok v) (Right res) = Right $ (name, v) : res

-- | Helper function to tranform JSON Result to Either RpcError b.

-- Note: For now we really only use it for b s.t. Rpc c b for some c

fromJResultToRes :: J.Result a -> (a -> b) -> ERpcError b

fromJResultToRes (J.Error v) _ = Left $ JsonDecodeError v

fromJResultToRes (J.Ok v) f = Right $ f v

-- | Helper function transforming JSValue to Rpc result type.

fromJSValueToRes :: (J.JSON a) => J.JSValue -> (a -> b) -> ERpcError b

fromJSValueToRes val = fromJResultToRes (J.readJSON val)

-- * RPC calls and results

-- ** Instance info

-- | InstanceInfo

--   Returns information about a single instance.

$(buildObject "RpcCallInstanceInfo" "rpcCallInstInfo"

  [ simpleField "instance" [t| String |]

  , simpleField "hname" [t| Hypervisor |]

  ])

$(buildObject "InstanceInfo" "instInfo"

  [ simpleField "memory" [t| Int|]

  , simpleField "state"  [t| String |] -- It depends on hypervisor :(

  , simpleField "vcpus"  [t| Int |]

  , simpleField "time"   [t| Int |]

  ])

-- This is optional here because the result may be empty if instance is

-- not on a node - and this is not considered an error.

$(buildObject "RpcResultInstanceInfo" "rpcResInstInfo"

  [ optionalField $ simpleField "inst_info" [t| InstanceInfo |]])

instance RpcCall RpcCallInstanceInfo where

  rpcCallName _          = "instance_info"

  rpcCallTimeout _       = rpcTimeoutToRaw Urgent

  rpcCallAcceptOffline _ = False

  rpcCallData _ call     = J.encode

    ( rpcCallInstInfoInstance call

    , rpcCallInstInfoHname call

    )

instance Rpc RpcCallInstanceInfo RpcResultInstanceInfo where

  rpcResultFill _ res =

    case res of

      J.JSObject res' ->

        case J.fromJSObject res' of

          [] -> Right $ RpcResultInstanceInfo Nothing

          _ -> fromJSValueToRes res (RpcResultInstanceInfo . Just)

      _ -> Left $ JsonDecodeError

           ("Expected JSObject, got " ++ show (pp_value res))

-- ** AllInstancesInfo

-- | AllInstancesInfo

--   Returns information about all running instances on the given nodes

$(buildObject "RpcCallAllInstancesInfo" "rpcCallAllInstInfo"

  [ simpleField "hypervisors" [t| [Hypervisor] |] ])

$(buildObject "RpcResultAllInstancesInfo" "rpcResAllInstInfo"

  [ simpleField "instances" [t| [(String, InstanceInfo)] |] ])

instance RpcCall RpcCallAllInstancesInfo where

  rpcCallName _          = "all_instances_info"

  rpcCallTimeout _       = rpcTimeoutToRaw Urgent

  rpcCallAcceptOffline _ = False

  rpcCallData _ call     = J.encode [rpcCallAllInstInfoHypervisors call]

instance Rpc RpcCallAllInstancesInfo RpcResultAllInstancesInfo where

  -- FIXME: Is there a simpler way to do it?

  rpcResultFill _ res =

    case res of

      J.JSObject res' ->

        let res'' = map (second J.readJSON) (J.fromJSObject res')

                        :: [(String, J.Result InstanceInfo)] in

        case sanitizeDictResults res'' of

          Left err -> Left err

          Right insts -> Right $ RpcResultAllInstancesInfo insts

      _ -> Left $ JsonDecodeError

           ("Expected JSObject, got " ++ show (pp_value res))

-- ** InstanceList

-- | InstanceList

-- Returns the list of running instances on the given nodes.

$(buildObject "RpcCallInstanceList" "rpcCallInstList"

  [ simpleField "hypervisors" [t| [Hypervisor] |] ])

$(buildObject "RpcResultInstanceList" "rpcResInstList"

  [ simpleField "instances" [t| [String] |] ])

instance RpcCall RpcCallInstanceList where

  rpcCallName _          = "instance_list"

  rpcCallTimeout _       = rpcTimeoutToRaw Urgent

  rpcCallAcceptOffline _ = False

  rpcCallData _ call     = J.encode [rpcCallInstListHypervisors call]

instance Rpc RpcCallInstanceList RpcResultInstanceList where

  rpcResultFill _ res = fromJSValueToRes res RpcResultInstanceList

-- ** NodeInfo

-- | NodeInfo

-- Return node information.

$(buildObject "RpcCallNodeInfo" "rpcCallNodeInfo"

  [ simpleField "volume_groups" [t| [String] |]

  , simpleField "hypervisors" [t| [Hypervisor] |]

  , simpleField "exclusive_storage" [t| Map.Map String Bool |]

  ])

$(buildObject "VgInfo" "vgInfo"

  [ simpleField "name" [t| String |]

  , optionalField $ simpleField "vg_free" [t| Int |]

  , optionalField $ simpleField "vg_size" [t| Int |]

  ])

-- | We only provide common fields as described in hv_base.py.

$(buildObject "HvInfo" "hvInfo"

  [ simpleField "memory_total" [t| Int |]

  , simpleField "memory_free" [t| Int |]

  , simpleField "memory_dom0" [t| Int |]

  , simpleField "cpu_total" [t| Int |]

  , simpleField "cpu_nodes" [t| Int |]

  , simpleField "cpu_sockets" [t| Int |]

  ])

$(buildObject "RpcResultNodeInfo" "rpcResNodeInfo"

  [ simpleField "boot_id" [t| String |]

  , simpleField "vg_info" [t| [VgInfo] |]

  , simpleField "hv_info" [t| [HvInfo] |]

  ])

instance RpcCall RpcCallNodeInfo where

  rpcCallName _          = "node_info"

  rpcCallTimeout _       = rpcTimeoutToRaw Urgent

  rpcCallAcceptOffline _ = False

  rpcCallData n call     = J.encode

    ( rpcCallNodeInfoVolumeGroups call

    , rpcCallNodeInfoHypervisors call

    , fromMaybe (error $ "Programmer error: missing parameter for node named "

                         ++ nodeName n)

                $ Map.lookup (nodeName n) (rpcCallNodeInfoExclusiveStorage call)

    )

instance Rpc RpcCallNodeInfo RpcResultNodeInfo where

  rpcResultFill _ res =

    fromJSValueToRes res (\(b, vg, hv) -> RpcResultNodeInfo b vg hv)

-- ** Version

-- | Version

-- Query node version.

-- Note: We can't use THH as it does not know what to do with empty dict

data RpcCallVersion = RpcCallVersion {}

  deriving (Show, Eq)

instance J.JSON RpcCallVersion where

  showJSON _ = J.JSNull

  readJSON J.JSNull = return RpcCallVersion

  readJSON _ = fail "Unable to read RpcCallVersion"

$(buildObject "RpcResultVersion" "rpcResultVersion"

  [ simpleField "version" [t| Int |]

  ])

instance RpcCall RpcCallVersion where

  rpcCallName _          = "version"

  rpcCallTimeout _       = rpcTimeoutToRaw Urgent

  rpcCallAcceptOffline _ = True

  rpcCallData _          = J.encode

instance Rpc RpcCallVersion RpcResultVersion where

  rpcResultFill _ res = fromJSValueToRes res RpcResultVersion

-- ** StorageList

-- | StorageList

-- FIXME: This may be moved to Objects

$(declareSADT "StorageField"

  [ ( "SFUsed",        'C.sfUsed)

  , ( "SFName",        'C.sfName)

  , ( "SFAllocatable", 'C.sfAllocatable)

  , ( "SFFree",        'C.sfFree)

  , ( "SFSize",        'C.sfSize)

  ])

$(makeJSONInstance ''StorageField)

$(buildObject "RpcCallStorageList" "rpcCallStorageList"

  [ simpleField "su_name" [t| StorageType |]

  , simpleField "su_args" [t| [String] |]

  , simpleField "name"    [t| String |]

  , simpleField "fields"  [t| [StorageField] |]

  ])

-- FIXME: The resulting JSValues should have types appropriate for their

-- StorageField value: Used -> Bool, Name -> String etc

$(buildObject "RpcResultStorageList" "rpcResStorageList"

  [ simpleField "storage" [t| [[(StorageField, J.JSValue)]] |] ])

instance RpcCall RpcCallStorageList where

  rpcCallName _          = "storage_list"

  rpcCallTimeout _       = rpcTimeoutToRaw Normal

  rpcCallAcceptOffline _ = False

  rpcCallData _ call     = J.encode

    ( rpcCallStorageListSuName call

    , rpcCallStorageListSuArgs call

    , rpcCallStorageListName call

    , rpcCallStorageListFields call

    )

instance Rpc RpcCallStorageList RpcResultStorageList where

  rpcResultFill call res =

    let sfields = rpcCallStorageListFields call in

    fromJSValueToRes res (RpcResultStorageList . map (zip sfields))

-- ** TestDelay

-- | Call definition for test delay.

$(buildObject "RpcCallTestDelay" "rpcCallTestDelay"

  [ simpleField "duration" [t| Double |]

  ])

-- | Result definition for test delay.

data RpcResultTestDelay = RpcResultTestDelay

                          deriving Show

-- | Custom JSON instance for null result.

instance J.JSON RpcResultTestDelay where

  showJSON _        = J.JSNull

  readJSON J.JSNull = return RpcResultTestDelay

  readJSON _        = fail "Unable to read RpcResultTestDelay"

instance RpcCall RpcCallTestDelay where

  rpcCallName _          = "test_delay"

  rpcCallTimeout         = ceiling . (+ 5) . rpcCallTestDelayDuration

  rpcCallAcceptOffline _ = False

  rpcCallData _ call     = J.encode [rpcCallTestDelayDuration call]

instance Rpc RpcCallTestDelay RpcResultTestDelay where

  rpcResultFill _ res = fromJSValueToRes res id