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{-# LANGUAGE BangPatterns #-}

{-| Implementation of the Ganeti Query2 server.

-}

{-

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.Query.Server

  ( ConfigReader

  , prepQueryD

  , runQueryD

  ) where

import Control.Applicative

import Control.Concurrent

import Control.Exception

import Data.Bits (bitSize)

import Data.Maybe

import qualified Network.Socket as S

import qualified Text.JSON as J

import Text.JSON (showJSON, JSValue(..))

import System.Info (arch)

import qualified Ganeti.Constants as C

import Ganeti.Errors

import qualified Ganeti.Path as Path

import Ganeti.Daemon

import Ganeti.Objects

import qualified Ganeti.Config as Config

import Ganeti.BasicTypes

import Ganeti.Logging

import Ganeti.Luxi

import Ganeti.OpCodes (TagObject(..))

import qualified Ganeti.Query.Language as Qlang

import qualified Ganeti.Query.Cluster as QCluster

import Ganeti.Query.Query

import Ganeti.Query.Filter (FilterConstructor, makeSimpleFilter

                           , makeHostnameFilter)

-- | A type for functions that can return the configuration when

-- executed.

type ConfigReader = IO (Result ConfigData)

-- | Helper for classic queries.

handleClassicQuery :: ConfigData      -- ^ Cluster config

                   -> Qlang.ItemType  -- ^ Query type

                   -> [Either String Integer] -- ^ Requested names

                                              -- (empty means all)

                   -> [String]        -- ^ Requested fields

                   -> Maybe FilterConstructor -- ^ the filter algorithm

                                              -- to be used, defaults to

                                              -- makeSimpleFilter

                   -> Bool            -- ^ Whether to do sync queries or not

                   -> IO (GenericResult GanetiException JSValue)

handleClassicQuery _ _ _ _ _ True =

  return . Bad $ OpPrereqError "Sync queries are not allowed" ECodeInval

handleClassicQuery cfg qkind names fields filterconstr _ = do

  let fltcon = fromMaybe makeSimpleFilter filterconstr

      flt = fltcon (nameField qkind) names

  qr <- query cfg True (Qlang.Query qkind fields flt)

  return $ showJSON <$> (qr >>= queryCompat)

-- | Minimal wrapper to handle the missing config case.

handleCallWrapper :: Result ConfigData -> LuxiOp -> IO (ErrorResult JSValue)

handleCallWrapper (Bad msg) _ =

  return . Bad . ConfigurationError $

           "I do not have access to a valid configuration, cannot\

           \ process queries: " ++ msg

handleCallWrapper (Ok config) op = handleCall config op

-- | Actual luxi operation handler.

handleCall :: ConfigData -> LuxiOp -> IO (ErrorResult JSValue)

handleCall cdata QueryClusterInfo =

  let cluster = configCluster cdata

      master = QCluster.clusterMasterNodeName cdata

      hypervisors = clusterEnabledHypervisors cluster

      diskTemplates = clusterEnabledDiskTemplates cluster

      def_hv = case hypervisors of

                 x:_ -> showJSON x

                 [] -> JSNull

      bits = show (bitSize (0::Int)) ++ "bits"

      arch_tuple = [bits, arch]

      obj = [ ("software_version", showJSON C.releaseVersion)

            , ("protocol_version", showJSON C.protocolVersion)

            , ("config_version", showJSON C.configVersion)

            , ("os_api_version", showJSON $ maximum C.osApiVersions)

            , ("export_version", showJSON C.exportVersion)

            , ("architecture", showJSON arch_tuple)

            , ("name", showJSON $ clusterClusterName cluster)

            , ("master", showJSON (case master of

                                     Ok name -> name

                                     _ -> undefined))

            , ("default_hypervisor", def_hv)

            , ("enabled_hypervisors", showJSON hypervisors)

            , ("hvparams", showJSON $ clusterHvparams cluster)

            , ("os_hvp", showJSON $ clusterOsHvp cluster)

            , ("beparams", showJSON $ clusterBeparams cluster)

            , ("osparams", showJSON $ clusterOsparams cluster)

            , ("ipolicy", showJSON $ clusterIpolicy cluster)

            , ("nicparams", showJSON $ clusterNicparams cluster)

            , ("ndparams", showJSON $ clusterNdparams cluster)

            , ("diskparams", showJSON $ clusterDiskparams cluster)

            , ("candidate_pool_size",

               showJSON $ clusterCandidatePoolSize cluster)

            , ("master_netdev",  showJSON $ clusterMasterNetdev cluster)

            , ("master_netmask", showJSON $ clusterMasterNetmask cluster)

            , ("use_external_mip_script",

               showJSON $ clusterUseExternalMipScript cluster)

            , ("volume_group_name",

               maybe JSNull showJSON (clusterVolumeGroupName cluster))

            , ("drbd_usermode_helper",

               maybe JSNull showJSON (clusterDrbdUsermodeHelper cluster))

            , ("file_storage_dir", showJSON $ clusterFileStorageDir cluster)

            , ("shared_file_storage_dir",

               showJSON $ clusterSharedFileStorageDir cluster)

            , ("maintain_node_health",

               showJSON $ clusterMaintainNodeHealth cluster)

            , ("ctime", showJSON $ clusterCtime cluster)

            , ("mtime", showJSON $ clusterMtime cluster)

            , ("uuid", showJSON $ clusterUuid cluster)

            , ("tags", showJSON $ clusterTags cluster)

            , ("uid_pool", showJSON $ clusterUidPool cluster)

            , ("default_iallocator",

               showJSON $ clusterDefaultIallocator cluster)

            , ("reserved_lvs", showJSON $ clusterReservedLvs cluster)

            , ("primary_ip_version",

               showJSON . ipFamilyToVersion $ clusterPrimaryIpFamily cluster)

            , ("prealloc_wipe_disks",

               showJSON $ clusterPreallocWipeDisks cluster)

            , ("hidden_os", showJSON $ clusterHiddenOs cluster)

            , ("blacklisted_os", showJSON $ clusterBlacklistedOs cluster)

            , ("enabled_disk_templates", showJSON diskTemplates)

            ]

  in case master of

    Ok _ -> return . Ok . J.makeObj $ obj

    Bad ex -> return $ Bad ex

handleCall cfg (QueryTags kind) =

  let tags = case kind of

               TagCluster       -> Ok . clusterTags $ configCluster cfg

               TagGroup    name -> groupTags <$> Config.getGroup    cfg name

               TagNode     name -> nodeTags  <$> Config.getNode     cfg name

               TagInstance name -> instTags  <$> Config.getInstance cfg name

  in return (J.showJSON <$> tags)

handleCall cfg (Query qkind qfields qfilter) = do

  result <- query cfg True (Qlang.Query qkind qfields qfilter)

  return $ J.showJSON <$> result

handleCall _ (QueryFields qkind qfields) = do

  let result = queryFields (Qlang.QueryFields qkind qfields)

  return $ J.showJSON <$> result

handleCall cfg (QueryNodes names fields lock) =

  handleClassicQuery cfg (Qlang.ItemTypeOpCode Qlang.QRNode)

    (map Left names) fields (Just makeHostnameFilter) lock

handleCall cfg (QueryGroups names fields lock) =

  handleClassicQuery cfg (Qlang.ItemTypeOpCode Qlang.QRGroup)

    (map Left names) fields Nothing lock

handleCall cfg (QueryJobs names fields) =

  handleClassicQuery cfg (Qlang.ItemTypeLuxi Qlang.QRJob)

    (map (Right . fromIntegral . fromJobId) names)  fields Nothing False

handleCall _ op =

  return . Bad $

    GenericError ("Luxi call '" ++ strOfOp op ++ "' not implemented")

-- | Given a decoded luxi request, executes it and sends the luxi

-- response back to the client.

handleClientMsg :: Client -> ConfigReader -> LuxiOp -> IO Bool

handleClientMsg client creader args = do

  cfg <- creader

  logDebug $ "Request: " ++ show args

  call_result <- handleCallWrapper cfg args

  (!status, !rval) <-

    case call_result of

      Bad err -> do

        logWarning $ "Failed to execute request " ++ show args ++ ": "

                     ++ show err

        return (False, showJSON err)

      Ok result -> do

        -- only log the first 2,000 chars of the result

        logDebug $ "Result (truncated): " ++ take 2000 (J.encode result)

        logInfo $ "Successfully handled " ++ strOfOp args

        return (True, result)

  sendMsg client $ buildResponse status rval

  return True

-- | Handles one iteration of the client protocol: receives message,

-- checks it for validity and decodes it, returns response.

handleClient :: Client -> ConfigReader -> IO Bool

handleClient client creader = do

  !msg <- recvMsgExt client

  case msg of

    RecvConnClosed -> logDebug "Connection closed" >> return False

    RecvError err -> logWarning ("Error during message receiving: " ++ err) >>

                     return False

    RecvOk payload ->

      case validateCall payload >>= decodeCall of

        Bad err -> do

             let errmsg = "Failed to parse request: " ++ err

             logWarning errmsg

             sendMsg client $ buildResponse False (showJSON errmsg)

             return False

        Ok args -> handleClientMsg client creader args

-- | Main client loop: runs one loop of 'handleClient', and if that

-- doesn't report a finished (closed) connection, restarts itself.

clientLoop :: Client -> ConfigReader -> IO ()

clientLoop client creader = do

  result <- handleClient client creader

  if result

    then clientLoop client creader

    else closeClient client

-- | Main loop: accepts clients, forks an I/O thread to handle that

-- client, and then restarts.

mainLoop :: ConfigReader -> S.Socket -> IO ()

mainLoop creader socket = do

  client <- acceptClient socket

  _ <- forkIO $ clientLoop client creader

  mainLoop creader socket

-- | Function that prepares the server socket.

prepQueryD :: Maybe FilePath -> IO (FilePath, S.Socket)

prepQueryD fpath = do

  def_socket <- Path.defaultQuerySocket

  let socket_path = fromMaybe def_socket fpath

  cleanupSocket socket_path

  s <- describeError "binding to the Luxi socket"

         Nothing (Just socket_path) $ getServer socket_path

  return (socket_path, s)

-- | Main function that runs the query endpoint.

runQueryD :: (FilePath, S.Socket) -> ConfigReader -> IO ()

runQueryD (socket_path, server) creader =

  finally

    (mainLoop creader server)

    (closeServer socket_path server)