Synnefo » snf-ganeti » ganeti-local

{-| Implementation of the iallocator interface.

-}

{-

Copyright (C) 2009, 2010, 2011 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.HTools.IAlloc

    ( parseData

    , formatResponse

    ) where

import Data.Either ()

import Data.Maybe (fromMaybe)

import Control.Monad

import Text.JSON (JSObject, JSValue(JSBool, JSString, JSArray),

                  makeObj, encodeStrict, decodeStrict,

                  fromJSObject, toJSString)

import qualified Ganeti.HTools.Container as Container

import qualified Ganeti.HTools.Group as Group

import qualified Ganeti.HTools.Node as Node

import qualified Ganeti.HTools.Instance as Instance

import qualified Ganeti.Constants as C

import Ganeti.HTools.Loader

import Ganeti.HTools.Utils

import Ganeti.HTools.Types

-- | Parse the basic specifications of an instance.

--

-- Instances in the cluster instance list and the instance in an

-- 'Allocate' request share some common properties, which are read by

-- this function.

parseBaseInstance :: String

                  -> [(String, JSValue)]

                  -> Result (String, Instance.Instance)

parseBaseInstance n a = do

  let extract x = tryFromObj ("invalid data for instance '" ++ n ++ "'") a x

  disk  <- extract "disk_space_total"

  mem   <- extract "memory"

  vcpus <- extract "vcpus"

  tags  <- extract "tags"

  let running = "running"

  return (n, Instance.create n mem disk vcpus running tags True 0 0)

-- | Parses an instance as found in the cluster instance listg.

parseInstance :: NameAssoc        -- ^ The node name-to-index association list

              -> String           -- ^ The name of the instance

              -> [(String, JSValue)] -- ^ The JSON object

              -> Result (String, Instance.Instance)

parseInstance ktn n a = do

  base <- parseBaseInstance n a

  nodes <- fromObj a "nodes"

  pnode <- if null nodes

           then Bad $ "empty node list for instance " ++ n

           else readEitherString $ head nodes

  pidx <- lookupNode ktn n pnode

  let snodes = tail nodes

  sidx <- (if null snodes then return Node.noSecondary

           else readEitherString (head snodes) >>= lookupNode ktn n)

  return (n, Instance.setBoth (snd base) pidx sidx)

-- | Parses a node as found in the cluster node list.

parseNode :: NameAssoc           -- ^ The group association

          -> String              -- ^ The node's name

          -> [(String, JSValue)] -- ^ The JSON object

          -> Result (String, Node.Node)

parseNode ktg n a = do

  let desc = "invalid data for node '" ++ n ++ "'"

      extract x = tryFromObj desc a x

  offline <- extract "offline"

  drained <- extract "drained"

  guuid   <- extract "group"

  vm_capable  <- annotateResult desc $ maybeFromObj a "vm_capable"

  let vm_capable' = fromMaybe True vm_capable

  gidx <- lookupGroup ktg n guuid

  node <- (if offline || drained || not vm_capable'

           then return $ Node.create n 0 0 0 0 0 0 True gidx

           else do

             mtotal <- extract "total_memory"

             mnode  <- extract "reserved_memory"

             mfree  <- extract "free_memory"

             dtotal <- extract "total_disk"

             dfree  <- extract "free_disk"

             ctotal <- extract "total_cpus"

             return $ Node.create n mtotal mnode mfree

                    dtotal dfree ctotal False gidx)

  return (n, node)

-- | Parses a group as found in the cluster group list.

parseGroup :: String              -- ^ The group UUID

           -> [(String, JSValue)] -- ^ The JSON object

           -> Result (String, Group.Group)

parseGroup u a = do

  let extract x = tryFromObj ("invalid data for group '" ++ u ++ "'") a x

  name <- extract "name"

  apol <- extract "alloc_policy"

  return (u, Group.create name u apol)

-- | Top-level parser.

parseData :: String         -- ^ The JSON message as received from Ganeti

          -> Result Request -- ^ A (possible valid) request

parseData body = do

  decoded <- fromJResult "Parsing input IAllocator message" (decodeStrict body)

  let obj = fromJSObject decoded

      extrObj x = tryFromObj "invalid iallocator message" obj x

  -- request parser

  request <- liftM fromJSObject (extrObj "request")

  let extrReq x = tryFromObj "invalid request dict" request x

  -- existing group parsing

  glist <- liftM fromJSObject (extrObj "nodegroups")

  gobj <- mapM (\(x, y) -> asJSObject y >>= parseGroup x . fromJSObject) glist

  let (ktg, gl) = assignIndices gobj

  -- existing node parsing

  nlist <- liftM fromJSObject (extrObj "nodes")

  nobj <- mapM (\(x,y) ->

                    asJSObject y >>= parseNode ktg x . fromJSObject) nlist

  let (ktn, nl) = assignIndices nobj

  -- existing instance parsing

  ilist <- extrObj "instances"

  let idata = fromJSObject ilist

  iobj <- mapM (\(x,y) ->

                    asJSObject y >>= parseInstance ktn x . fromJSObject) idata

  let (kti, il) = assignIndices iobj

  -- cluster tags

  ctags <- extrObj "cluster_tags"

  cdata <- mergeData [] [] [] (ClusterData gl nl il ctags)

  let map_n = cdNodes cdata

  optype <- extrReq "type"

  rqtype <-

      case () of

        _ | optype == C.iallocatorModeAlloc ->

              do

                rname     <- extrReq "name"

                req_nodes <- extrReq "required_nodes"

                inew      <- parseBaseInstance rname request

                let io = snd inew

                return $ Allocate io req_nodes

          | optype == C.iallocatorModeReloc ->

              do

                rname     <- extrReq "name"

                ridx      <- lookupInstance kti rname

                req_nodes <- extrReq "required_nodes"

                ex_nodes  <- extrReq "relocate_from"

                ex_idex   <- mapM (Container.findByName map_n) ex_nodes

                return $ Relocate ridx req_nodes (map Node.idx ex_idex)

          | optype == C.iallocatorModeMevac ->

              do

                ex_names <- extrReq "evac_nodes"

                ex_nodes <- mapM (Container.findByName map_n) ex_names

                let ex_ndx = map Node.idx ex_nodes

                return $ Evacuate ex_ndx

          | otherwise -> fail ("Invalid request type '" ++ optype ++ "'")

  return $ Request rqtype cdata

-- | Format the result

formatRVal :: RqType -> [Node.AllocElement] -> JSValue

formatRVal _ [] = JSArray []

formatRVal (Evacuate _) elems =

    let sols = map (\(_, inst, nl, _) -> Instance.name inst : map Node.name nl)

               elems

        jsols = map (JSArray . map (JSString . toJSString)) sols

    in JSArray jsols

formatRVal _ elems =

    let (_, _, nodes, _) = head elems

        nodes' = map Node.name nodes

    in JSArray $ map (JSString . toJSString) nodes'

-- | Formats the response into a valid IAllocator response message.

formatResponse :: Bool     -- ^ Whether the request was successful

               -> String   -- ^ Information text

               -> RqType   -- ^ Request type

               -> [Node.AllocElement] -- ^ The resulting allocations

               -> String   -- ^ The JSON-formatted message

formatResponse success info rq elems =

    let

        e_success = ("success", JSBool success)

        e_info = ("info", JSString . toJSString $ info)

        e_nodes = ("nodes", formatRVal rq elems)

    in encodeStrict $ makeObj [e_success, e_info, e_nodes]