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{-# LANGUAGE TemplateHaskell #-}

{-| Implementation of the Ganeti LUXI interface.

-}

{-

Copyright (C) 2009, 2010, 2011, 2012 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.Luxi

  ( LuxiOp(..)

  , ResultStatus(..)

  , LuxiReq(..)

  , Client

  , JobId

  , RecvResult(..)

  , strOfOp

  , checkRS

  , getClient

  , getServer

  , acceptClient

  , closeClient

  , closeServer

  , callMethod

  , submitManyJobs

  , queryJobsStatus

  , buildCall

  , buildResponse

  , validateCall

  , decodeCall

  , recvMsg

  , recvMsgExt

  , sendMsg

  ) where

import Control.Exception (catch)

import Data.IORef

import Data.Ratio (numerator, denominator)

import qualified Data.ByteString as B

import qualified Data.ByteString.UTF8 as UTF8

import Data.Word (Word8)

import Control.Monad

import Prelude hiding (catch)

import Text.JSON (encodeStrict, decodeStrict)

import qualified Text.JSON as J

import Text.JSON.Types

import System.Directory (removeFile)

import System.IO (hClose, hFlush, hWaitForInput, Handle, IOMode(..))

import System.IO.Error (isEOFError)

import System.Timeout

import qualified Network.Socket as S

import Ganeti.HTools.JSON

import Ganeti.HTools.Types

import Ganeti.HTools.Utils

import Ganeti.Constants

import Ganeti.Jobs (JobStatus)

import Ganeti.OpCodes (OpCode)

import qualified Ganeti.Qlang as Qlang

import Ganeti.THH

-- * Utility functions

-- | Wrapper over System.Timeout.timeout that fails in the IO monad.

withTimeout :: Int -> String -> IO a -> IO a

withTimeout secs descr action = do

  result <- timeout (secs * 1000000) action

  case result of

    Nothing -> fail $ "Timeout in " ++ descr

    Just v -> return v

-- * Generic protocol functionality

-- | Result of receiving a message from the socket.

data RecvResult = RecvConnClosed    -- ^ Connection closed

                | RecvError String  -- ^ Any other error

                | RecvOk String     -- ^ Successfull receive

                  deriving (Show, Read, Eq)

-- | The Ganeti job type.

type JobId = Int

-- | Currently supported Luxi operations and JSON serialization.

$(genLuxiOp "LuxiOp"

  [(luxiReqQuery,

    [ ("what",    [t| Qlang.ItemType |])

    , ("fields",  [t| [String]  |])

    , ("qfilter", [t| Qlang.Filter |])

    ])

  , (luxiReqQueryNodes,

     [ ("names",  [t| [String] |])

     , ("fields", [t| [String] |])

     , ("lock",   [t| Bool     |])

     ])

  , (luxiReqQueryGroups,

     [ ("names",  [t| [String] |])

     , ("fields", [t| [String] |])

     , ("lock",   [t| Bool     |])

     ])

  , (luxiReqQueryInstances,

     [ ("names",  [t| [String] |])

     , ("fields", [t| [String] |])

     , ("lock",   [t| Bool     |])

     ])

  , (luxiReqQueryJobs,

     [ ("ids",    [t| [Int]    |])

     , ("fields", [t| [String] |])

     ])

  , (luxiReqQueryExports,

     [ ("nodes", [t| [String] |])

     , ("lock",  [t| Bool     |])

     ])

  , (luxiReqQueryConfigValues,

     [ ("fields", [t| [String] |]) ]

    )

  , (luxiReqQueryClusterInfo, [])

  , (luxiReqQueryTags,

     [ ("kind", [t| String |])

     , ("name", [t| String |])

     ])

  , (luxiReqSubmitJob,

     [ ("job", [t| [OpCode] |]) ]

    )

  , (luxiReqSubmitManyJobs,

     [ ("ops", [t| [[OpCode]] |]) ]

    )

  , (luxiReqWaitForJobChange,

     [ ("job",      [t| Int     |])

     , ("fields",   [t| [String]|])

     , ("prev_job", [t| JSValue |])

     , ("prev_log", [t| JSValue |])

     , ("tmout",    [t| Int     |])

     ])

  , (luxiReqArchiveJob,

     [ ("job", [t| Int |]) ]

    )

  , (luxiReqAutoArchiveJobs,

     [ ("age",   [t| Int |])

     , ("tmout", [t| Int |])

     ])

  , (luxiReqCancelJob,

     [ ("job", [t| Int |]) ]

    )

  , (luxiReqSetDrainFlag,

     [ ("flag", [t| Bool |]) ]

    )

  , (luxiReqSetWatcherPause,

     [ ("duration", [t| Double |]) ]

    )

  ])

$(makeJSONInstance ''LuxiReq)

-- | The serialisation of LuxiOps into strings in messages.

$(genStrOfOp ''LuxiOp "strOfOp")

$(declareIADT "ResultStatus"

  [ ("RSNormal", 'rsNormal)

  , ("RSUnknown", 'rsUnknown)

  , ("RSNoData", 'rsNodata)

  , ("RSUnavailable", 'rsUnavail)

  , ("RSOffline", 'rsOffline)

  ])

$(makeJSONInstance ''ResultStatus)

-- | Type holding the initial (unparsed) Luxi call.

data LuxiCall = LuxiCall LuxiReq JSValue

-- | Check that ResultStatus is success or fail with descriptive message.

checkRS :: (Monad m) => ResultStatus -> a -> m a

checkRS RSNormal val    = return val

checkRS RSUnknown _     = fail "Unknown field"

checkRS RSNoData _      = fail "No data for a field"

checkRS RSUnavailable _ = fail "Ganeti reports unavailable data"

checkRS RSOffline _     = fail "Ganeti reports resource as offline"

-- | The end-of-message separator.

eOM :: Word8

eOM = 3

-- | The end-of-message encoded as a ByteString.

bEOM :: B.ByteString

bEOM = B.singleton eOM

-- | Valid keys in the requests and responses.

data MsgKeys = Method

             | Args

             | Success

             | Result

-- | The serialisation of MsgKeys into strings in messages.

$(genStrOfKey ''MsgKeys "strOfKey")

-- | Luxi client encapsulation.

data Client = Client { socket :: Handle           -- ^ The socket of the client

                     , rbuf :: IORef B.ByteString -- ^ Already received buffer

                     }

-- | Connects to the master daemon and returns a luxi Client.

getClient :: String -> IO Client

getClient path = do

  s <- S.socket S.AF_UNIX S.Stream S.defaultProtocol

  withTimeout connTimeout "creating luxi connection" $

              S.connect s (S.SockAddrUnix path)

  rf <- newIORef B.empty

  h <- S.socketToHandle s ReadWriteMode

  return Client { socket=h, rbuf=rf }

-- | Creates and returns a server endpoint.

getServer :: FilePath -> IO S.Socket

getServer path = do

  s <- S.socket S.AF_UNIX S.Stream S.defaultProtocol

  S.bindSocket s (S.SockAddrUnix path)

  S.listen s 5 -- 5 is the max backlog

  return s

-- | Closes a server endpoint.

-- FIXME: this should be encapsulated into a nicer type.

closeServer :: FilePath -> S.Socket -> IO ()

closeServer path sock = do

  S.sClose sock

  removeFile path

-- | Accepts a client

acceptClient :: S.Socket -> IO Client

acceptClient s = do

  -- second return is the address of the client, which we ignore here

  (client_socket, _) <- S.accept s

  new_buffer <- newIORef B.empty

  handle <- S.socketToHandle client_socket ReadWriteMode

  return Client { socket=handle, rbuf=new_buffer }

-- | Closes the client socket.

closeClient :: Client -> IO ()

closeClient = hClose . socket

-- | Sends a message over a luxi transport.

sendMsg :: Client -> String -> IO ()

sendMsg s buf = withTimeout queryTimeout "sending luxi message" $ do

  let encoded = UTF8.fromString buf

      handle = socket s

  B.hPut handle encoded

  B.hPut handle bEOM

  hFlush handle

-- | Given a current buffer and the handle, it will read from the

-- network until we get a full message, and it will return that

-- message and the leftover buffer contents.

recvUpdate :: Handle -> B.ByteString -> IO (B.ByteString, B.ByteString)

recvUpdate handle obuf = do

  nbuf <- withTimeout queryTimeout "reading luxi response" $ do

            _ <- hWaitForInput handle (-1)

            B.hGetNonBlocking handle 4096

  let (msg, remaining) = B.break (eOM ==) nbuf

      newbuf = B.append obuf msg

  if B.null remaining

    then recvUpdate handle newbuf

    else return (newbuf, B.tail remaining)

-- | Waits for a message over a luxi transport.

recvMsg :: Client -> IO String

recvMsg s = do

  cbuf <- readIORef $ rbuf s

  let (imsg, ibuf) = B.break (eOM ==) cbuf

  (msg, nbuf) <-

    if B.null ibuf      -- if old buffer didn't contain a full message

      then recvUpdate (socket s) cbuf   -- then we read from network

      else return (imsg, B.tail ibuf)   -- else we return data from our buffer

  writeIORef (rbuf s) nbuf

  return $ UTF8.toString msg

-- | Extended wrapper over recvMsg.

recvMsgExt :: Client -> IO RecvResult

recvMsgExt s =

  catch (liftM RecvOk (recvMsg s)) $ \e ->

    if isEOFError e

      then return RecvConnClosed

      else return $ RecvError (show e)

-- | Serialize a request to String.

buildCall :: LuxiOp  -- ^ The method

          -> String  -- ^ The serialized form

buildCall lo =

  let ja = [ (strOfKey Method, J.showJSON $ strOfOp lo)

           , (strOfKey Args, opToArgs lo)

           ]

      jo = toJSObject ja

  in encodeStrict jo

-- | Serialize the response to String.

buildResponse :: Bool    -- ^ Success

              -> JSValue -- ^ The arguments

              -> String  -- ^ The serialized form

buildResponse success args =

  let ja = [ (strOfKey Success, JSBool success)

           , (strOfKey Result, args)]

      jo = toJSObject ja

  in encodeStrict jo

-- | Check that luxi request contains the required keys and parse it.

validateCall :: String -> Result LuxiCall

validateCall s = do

  arr <- fromJResult "parsing top-level luxi message" $

         decodeStrict s::Result (JSObject JSValue)

  let aobj = fromJSObject arr

  call <- fromObj aobj (strOfKey Method)::Result LuxiReq

  args <- fromObj aobj (strOfKey Args)

  return (LuxiCall call args)

-- | Converts Luxi call arguments into a 'LuxiOp' data structure.

--

-- This is currently hand-coded until we make it more uniform so that

-- it can be generated using TH.

decodeCall :: LuxiCall -> Result LuxiOp

decodeCall (LuxiCall call args) =

  case call of

    ReqQueryJobs -> do

              (jid, jargs) <- fromJVal args

              rid <- mapM parseJobId jid

              let rargs = map fromJSString jargs

              return $ QueryJobs rid rargs

    ReqQueryInstances -> do

              (names, fields, locking) <- fromJVal args

              return $ QueryInstances names fields locking

    ReqQueryNodes -> do

              (names, fields, locking) <- fromJVal args

              return $ QueryNodes names fields locking

    ReqQueryGroups -> do

              (names, fields, locking) <- fromJVal args

              return $ QueryGroups names fields locking

    ReqQueryClusterInfo -> do

              return QueryClusterInfo

    ReqQuery -> do

              (what, fields, qfilter) <- fromJVal args

              return $ Query what fields qfilter

    ReqSubmitJob -> do

              [ops1] <- fromJVal args

              ops2 <- mapM (fromJResult (luxiReqToRaw call) . J.readJSON) ops1

              return $ SubmitJob ops2

    ReqSubmitManyJobs -> do

              [ops1] <- fromJVal args

              ops2 <- mapM (fromJResult (luxiReqToRaw call) . J.readJSON) ops1

              return $ SubmitManyJobs ops2

    ReqWaitForJobChange -> do

              (jid, fields, pinfo, pidx, wtmout) <-

                -- No instance for 5-tuple, code copied from the

                -- json sources and adapted

                fromJResult "Parsing WaitForJobChange message" $

                case args of

                  JSArray [a, b, c, d, e] ->

                    (,,,,) `fmap`

                    J.readJSON a `ap`

                    J.readJSON b `ap`

                    J.readJSON c `ap`

                    J.readJSON d `ap`

                    J.readJSON e

                  _ -> J.Error "Not enough values"

              rid <- parseJobId jid

              return $ WaitForJobChange rid fields pinfo pidx wtmout

    ReqArchiveJob -> do

              [jid] <- fromJVal args

              rid <- parseJobId jid

              return $ ArchiveJob rid

    ReqAutoArchiveJobs -> do

              (age, tmout) <- fromJVal args

              return $ AutoArchiveJobs age tmout

    ReqQueryExports -> do

              (nodes, lock) <- fromJVal args

              return $ QueryExports nodes lock

    ReqQueryConfigValues -> do

              [fields] <- fromJVal args

              return $ QueryConfigValues fields

    ReqQueryTags -> do

              (kind, name) <- fromJVal args

              return $ QueryTags kind name

    ReqCancelJob -> do

              [job] <- fromJVal args

              rid <- parseJobId job

              return $ CancelJob rid

    ReqSetDrainFlag -> do

              [flag] <- fromJVal args

              return $ SetDrainFlag flag

    ReqSetWatcherPause -> do

              [duration] <- fromJVal args

              return $ SetWatcherPause duration

-- | Check that luxi responses contain the required keys and that the

-- call was successful.

validateResult :: String -> Result JSValue

validateResult s = do

  when (UTF8.replacement_char `elem` s) $

       fail "Failed to decode UTF-8, detected replacement char after decoding"

  oarr <- fromJResult "Parsing LUXI response"

          (decodeStrict s)::Result (JSObject JSValue)

  let arr = J.fromJSObject oarr

  status <- fromObj arr (strOfKey Success)::Result Bool

  let rkey = strOfKey Result

  if status

    then fromObj arr rkey

    else fromObj arr rkey >>= fail

-- | Generic luxi method call.

callMethod :: LuxiOp -> Client -> IO (Result JSValue)

callMethod method s = do

  sendMsg s $ buildCall method

  result <- recvMsg s

  let rval = validateResult result

  return rval

-- | Parses a job ID.

parseJobId :: JSValue -> Result JobId

parseJobId (JSString x) = tryRead "parsing job id" . fromJSString $ x

parseJobId (JSRational _ x) =

  if denominator x /= 1

    then Bad $ "Got fractional job ID from master daemon?! Value:" ++ show x

    -- FIXME: potential integer overflow here on 32-bit platforms

    else Ok . fromIntegral . numerator $ x

parseJobId x = Bad $ "Wrong type/value for job id: " ++ show x

-- | Parse job submission result.

parseSubmitJobResult :: JSValue -> Result JobId

parseSubmitJobResult (JSArray [JSBool True, v]) = parseJobId v

parseSubmitJobResult (JSArray [JSBool False, JSString x]) =

  Bad (fromJSString x)

parseSubmitJobResult v = Bad $ "Unknown result from the master daemon" ++

                         show v

-- | Specialized submitManyJobs call.

submitManyJobs :: Client -> [[OpCode]] -> IO (Result [JobId])

submitManyJobs s jobs = do

  rval <- callMethod (SubmitManyJobs jobs) s

  -- map each result (status, payload) pair into a nice Result ADT

  return $ case rval of

             Bad x -> Bad x

             Ok (JSArray r) -> mapM parseSubmitJobResult r

             x -> Bad ("Cannot parse response from Ganeti: " ++ show x)

-- | Custom queryJobs call.

queryJobsStatus :: Client -> [JobId] -> IO (Result [JobStatus])

queryJobsStatus s jids = do

  rval <- callMethod (QueryJobs jids ["status"]) s

  return $ case rval of

             Bad x -> Bad x

             Ok y -> case J.readJSON y::(J.Result [[JobStatus]]) of

                       J.Ok vals -> if any null vals

                                    then Bad "Missing job status field"

                                    else Ok (map head vals)

                       J.Error x -> Bad x