content: {-| Implementation of the iallocator interface.
  
  -}
  
  {-
  
  Copyright (C) 2009, 2010, 2011, 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.HTools.Backend.IAlloc
    ( readRequest
    , runIAllocator
    , processRelocate
    , loadData
    , formatAllocate
    , formatIAllocResult
    , formatMultiAlloc
    ) where
  
  import Data.Either ()
  import Data.Maybe (fromMaybe, isJust, fromJust)
  import Data.List
  import Control.Monad
  import System.Time (ClockTime, getClockTime)
  import Text.JSON (JSObject, JSValue(JSArray),
                    makeObj, encodeStrict, decodeStrict, fromJSObject, showJSON)
  
  import Ganeti.BasicTypes
  import qualified Ganeti.HTools.Cluster as Cluster
  import qualified Ganeti.HTools.Cluster.AllocationSolution as AllocSol
  import qualified Ganeti.HTools.Cluster.AllocateSecondary as AllocSecondary
  import qualified Ganeti.HTools.Cluster.Evacuate as Evacuate
  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.HTools.Nic as Nic
  import qualified Ganeti.Constants as C
  import Ganeti.HTools.AlgorithmParams (AlgorithmOptions(algRestrictToNodes))
  import Ganeti.HTools.CLI
  import Ganeti.HTools.Loader
  import Ganeti.HTools.Types
  import Ganeti.JSON (maybeFromObj, JSRecord, tryFromObj, toArray, asObjectList,
                      readEitherString, fromJResult, fromObj, fromObjWithDefault,
                      asJSObject)
  import Ganeti.Types ( EvacMode(ChangePrimary, ChangeSecondary)
                      , adminStateFromRaw, AdminState(..))
  import Ganeti.Utils
  
  {-# ANN module "HLint: ignore Eta reduce" #-}
  
  -- | Type alias for the result of an IAllocator call.
  type IAllocResult = (String, JSValue, Node.List, Instance.List)
  
  -- | Parse a NIC within an instance (in a creation request)
  parseNic :: String -> JSRecord -> Result Nic.Nic
  parseNic n a = do
    mac     <- maybeFromObj a "mac"
    ip      <- maybeFromObj a "ip"
    mode    <- maybeFromObj a "mode" >>= \m -> case m of
                 Just "bridged" -> Ok $ Just Nic.Bridged
                 Just "routed" -> Ok $ Just Nic.Routed
                 Just "openvswitch" -> Ok $ Just Nic.OpenVSwitch
                 Nothing -> Ok Nothing
                 _ -> Bad $ "invalid NIC mode in instance " ++ n
    link    <- maybeFromObj a "link"
    bridge  <- maybeFromObj a "bridge"
    network <- maybeFromObj a "network"
    return (Nic.create mac ip mode link bridge network)
  
  -- | 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
                    -> JSRecord
                    -> Result (String, Instance.Instance)
  parseBaseInstance n a = do
    let errorMessage = "invalid data for instance '" ++ n ++ "'"
    let extract x = tryFromObj errorMessage a x
    disk  <- extract "disk_space_total"
    jsdisks <- extract "disks" >>= toArray >>= asObjectList
    dsizes <- mapM (flip (tryFromObj errorMessage) "size" . fromJSObject) jsdisks
    dspindles <- mapM (annotateResult errorMessage .
                       flip maybeFromObj "spindles" . fromJSObject) jsdisks
    let disks = zipWith Instance.Disk dsizes dspindles
    mem   <- extract "memory"
    vcpus <- extract "vcpus"
    tags  <- extract "tags"
    dt    <- extract "disk_template"
    su    <- extract "spindle_use"
    nics  <- extract "nics" >>= toArray >>= asObjectList >>=
             mapM (parseNic n . fromJSObject)
    state <- (tryFromObj errorMessage a "admin_state" >>= adminStateFromRaw)
             `mplus` Ok AdminUp
    let getRunSt AdminOffline = StatusOffline
        getRunSt AdminDown = StatusDown
        getRunSt AdminUp = Running
    -- Not forthcoming by default.
    forthcoming <- extract "forthcoming" `orElse` Ok False
    return
      (n,
       Instance.create n mem disk disks vcpus (getRunSt state) tags
                       True 0 0 dt su nics forthcoming)
  
  -- | Parses an instance as found in the cluster instance list.
  parseInstance :: NameAssoc -- ^ The node name-to-index association list
                -> String    -- ^ The name of the instance
                -> JSRecord  -- ^ The JSON object
                -> Result (String, Instance.Instance)
  parseInstance ktn n a = do
    base <- parseBaseInstance n a
    nodes <- fromObj a "nodes"
    (pnode, snodes) <-
      case nodes of
        [] -> Bad $ "empty node list for instance " ++ n
        x:xs -> readEitherString x >>= \x' -> return (x', xs)
    pidx <- lookupNode ktn n pnode
    sidx <- case snodes of
              [] -> return Node.noSecondary
              x:_ -> readEitherString x >>= 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
            -> JSRecord    -- ^ 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
        extractDef def key = fromObjWithDefault a key def
    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
    ndparams <- extract "ndparams" >>= asJSObject
    -- Despite the fact that tags field is reported by iallocator.py,
    -- some tests don't contain tags field
    tags <- extractDef [] "tags"
    excl_stor <- tryFromObj desc (fromJSObject ndparams) "exclusive_storage"
    let live = not offline && vm_capable'
        lvextract def = eitherLive live def . extract
    sptotal <- if excl_stor
               then lvextract 0 "total_spindles"
               else tryFromObj desc (fromJSObject ndparams) "spindle_count"
    spfree <- lvextract 0 "free_spindles"
    mtotal <- lvextract 0.0 "total_memory"
    mnode  <- lvextract 0 "reserved_memory"
    mfree  <- lvextract 0 "free_memory"
    dtotal <- lvextract 0.0 "total_disk"
    dfree  <- lvextract 0 "free_disk"
    ctotal <- lvextract 0.0 "total_cpus"
    cnos <- lvextract 0 "reserved_cpus"
    let node = flip Node.setNodeTags tags $
               Node.create n mtotal mnode mfree dtotal dfree ctotal cnos
               (not live || drained) sptotal spfree gidx excl_stor
    return (n, node)
  
  -- | Parses a group as found in the cluster group list.
  parseGroup :: String     -- ^ The group UUID
             -> JSRecord   -- ^ 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"
    nets <- extract "networks"
    ipol <- extract "ipolicy"
    tags <- extract "tags"
    return (u, Group.create name u apol nets ipol tags)
  
  -- | Top-level parser.
  --
  -- The result is a tuple of eventual warning messages and the parsed
  -- request; if parsing the input data fails, we'll return a 'Bad'
  -- value.
  parseData :: ClockTime -- ^ The current time
            -> String -- ^ The JSON message as received from Ganeti
            -> Int -- ^ Static node memory size, see optStaticKvmNodeMemory
            -> Result ([String], Request) -- ^ Result tuple
  parseData now body static_n_mem = 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 extrFromReq r x = tryFromObj "invalid request dict" r x
    let extrReq x = extrFromReq 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"
    let ex_tags = extractExTags ctags
        dsrd_loc_tags = extractDesiredLocations ctags
        updateTags = updateExclTags ex_tags .
                     updateDesiredLocationTags dsrd_loc_tags
    -- hypervisor
    enabled_hypervisors <- extrObj "enabled_hypervisors"
    -- This is ugly, unfortunately the  IAllocator "API" (which is a CLI not an
    -- API to be precise) is different from other htools backends that receive
    -- the 'default_hypervisor' field. Normally there is no reason to have
    -- more than one hypervisor so in practice this should be fine. Ganeti 2.17
    -- exports the hv_stat per node field with the missing information.
    -- TODO: Remove, once the caller can get the correct nodes size on KVM.
    let nl2 = case enabled_hypervisors of
                hv : _ -> Container.map (`Node.setHypervisor` hv) nl
                _ -> nl
    cdata1 <- mergeData [] [] [] [] now (ClusterData gl nl2 il ctags defIPolicy)
    let (msgs, fix_nl) = updateMissing (cdNodes cdata1)
                                       (cdInstances cdata1)
                                       static_n_mem
        cdata = cdata1 { cdNodes = fix_nl }
        map_n = cdNodes cdata
        map_i = cdInstances cdata
        map_g = cdGroups cdata
    optype <- extrReq "type"
    rqtype <-
      case () of
        _ | optype == C.iallocatorModeAlloc ->
              do
                rname     <- extrReq "name"
                rgn       <- maybeFromObj request "group_name"
                rest_nodes <- maybeFromObj request "restrict-to-nodes"
                req_nodes <- extrReq "required_nodes"
                inew      <- parseBaseInstance rname request
                let io = updateTags $ snd inew
                return $ Allocate io (Cluster.AllocDetails req_nodes rgn)
                                  rest_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.iallocatorModeChgGroup ->
              do
                rl_names <- extrReq "instances"
                rl_insts <- mapM (liftM Instance.idx .
                                  Container.findByName map_i) rl_names
                gr_uuids <- extrReq "target_groups"
                gr_idxes <- mapM (liftM Group.idx .
                                  Container.findByName map_g) gr_uuids
                return $ ChangeGroup rl_insts gr_idxes
          | optype == C.iallocatorModeNodeEvac ->
              do
                rl_names <- extrReq "instances"
                rl_insts <- mapM (Container.findByName map_i) rl_names
                let rl_idx = map Instance.idx rl_insts
                rl_mode <- extrReq "evac_mode"
                return $ NodeEvacuate rl_idx rl_mode
          | optype == C.iallocatorModeMultiAlloc ->
              do
                arry <- extrReq "instances" :: Result [JSObject JSValue]
                let inst_reqs = map fromJSObject arry
                prqs <- forM inst_reqs (\r ->
                                 do
                                   rname     <- extrFromReq r "name"
                                   rgn       <- maybeFromObj request "group_name"
                                   req_nodes <- extrFromReq r "required_nodes"
                                   inew      <- parseBaseInstance rname r
                                   let io = updateTags $ snd inew
                                   return (io, Cluster.AllocDetails
                                                 req_nodes rgn))
                return $ MultiAllocate prqs
          | optype == C.iallocatorModeAllocateSecondary ->
              do
                rname <- extrReq "name"
                ridx  <- lookupInstance kti rname
                return $ AllocateSecondary ridx
          | otherwise -> fail ("Invalid request type '" ++ optype ++ "'")
    return (msgs, Request rqtype cdata)
  
  -- | Formats the result into a valid IAllocator response message.
  formatResponse :: Bool     -- ^ Whether the request was successful
                 -> String   -- ^ Information text
                 -> JSValue  -- ^ The JSON encoded result
                 -> String   -- ^ The full JSON-formatted message
  formatResponse success info result =
    let e_success = ("success", showJSON success)
        e_info = ("info", showJSON info)
        e_result = ("result", result)
    in encodeStrict $ makeObj [e_success, e_info, e_result]
  
  -- | Flatten the log of a solution into a string.
  describeSolution :: AllocSol.GenericAllocSolution a -> String
  describeSolution = intercalate ", " . AllocSol.asLog
  
  -- | Convert allocation/relocation results into the result format.
  formatAllocate :: Instance.List
                 -> AllocSol.GenericAllocSolution a
                 -> Result IAllocResult
  formatAllocate il as = do
    let info = describeSolution as
    case AllocSol.asSolution as of
      Nothing -> fail info
      Just (nl, inst, nodes, _) ->
        do
          let il' = Container.add (Instance.idx inst) inst il
          return (info, showJSON $ map Node.name nodes, nl, il')
  
  -- | Convert allocation/relocation results into the result format.
  formatAllocateSecondary :: Instance.List
                          -> AllocSol.GenericAllocSolution a
                          -> Result IAllocResult
  formatAllocateSecondary il as = do
    let info = describeSolution as
    case AllocSol.asSolution as of
      Nothing -> fail info
      Just (nl, inst, [_, snode], _) ->
        do
          let il' = Container.add (Instance.idx inst) inst il
          return (info, showJSON $ Node.name snode, nl, il')
      _ -> fail $ "Internal error (not a DRBD allocation); info was: " ++ info
  
  -- | Convert multi allocation results into the result format.
  formatMultiAlloc :: ( Node.List, Instance.List
                      , Cluster.GenericAllocSolutionList a)
                   -> Result IAllocResult
  formatMultiAlloc (fin_nl, fin_il, ars) =
    let rars = reverse ars
        (allocated, failed) = partition (isJust . AllocSol.asSolution . snd) rars
        aars = map (\(_, ar) ->
                       let (_, inst, nodes, _) = fromJust $ AllocSol.asSolution ar
                           iname = Instance.name inst
                           nnames = map Node.name nodes
                       in (iname, nnames)) allocated
        fars = map (\(inst, ar) ->
                       let iname = Instance.name inst
                       in (iname, describeSolution ar)) failed
        info = show (length failed) ++ " instances failed to allocate and " ++
               show (length allocated) ++ " were allocated successfully"
    in return (info, showJSON (aars, fars), fin_nl, fin_il)
  
  -- | Convert a node-evacuation/change group result.
  formatNodeEvac :: Group.List
                 -> Node.List
                 -> Instance.List
                 -> (Node.List, Instance.List, Evacuate.EvacSolution)
                 -> Result IAllocResult
  formatNodeEvac gl nl il (fin_nl, fin_il, es) =
    let iname = Instance.name . flip Container.find il
        nname = Node.name . flip Container.find nl
        gname = Group.name . flip Container.find gl
        fes = map (\(idx, msg) -> (iname idx, msg)) $ Evacuate.esFailed es
        mes = map (\(idx, gdx, ndxs) -> (iname idx, gname gdx, map nname ndxs))
              $ Evacuate.esMoved es
        failed = length fes
        moved  = length mes
        info = show failed ++ " instances failed to move and " ++ show moved ++
               " were moved successfully"
    in Ok (info, showJSON (mes, fes, Evacuate.esOpCodes es), fin_nl, fin_il)
  
  -- | Runs relocate for a single instance.
  --
  -- This is wrapper over the 'Cluster.tryNodeEvac' function that is run
  -- with a single instance (ours), and further it checks that the
  -- result it got (in the nodes field) is actually consistent, as
  -- tryNodeEvac is designed to output primarily an opcode list, not a
  -- node list.
  processRelocate :: AlgorithmOptions
                  -> Group.List      -- ^ The group list
                  -> Node.List       -- ^ The node list
                  -> Instance.List   -- ^ The instance list
                  -> Idx             -- ^ The index of the instance to move
                  -> Int             -- ^ The number of nodes required
                  -> [Ndx]           -- ^ Nodes which should not be used
                  -> Result (Node.List, Instance.List, [Ndx]) -- ^ Solution list
  processRelocate opts gl nl il idx 1 exndx = do
    let orig = Container.find idx il
        sorig = Instance.sNode orig
        porig = Instance.pNode orig
        mir_type = Instance.mirrorType orig
    (exp_node, node_type, reloc_type) <-
      case mir_type of
        MirrorNone -> fail "Can't relocate non-mirrored instances"
        MirrorInternal -> return (sorig, "secondary", ChangeSecondary)
        MirrorExternal -> return (porig, "primary", ChangePrimary)
    when (exndx /= [exp_node]) .
         -- FIXME: we can't use the excluded nodes here; the logic is
         -- already _but only partially_ implemented in tryNodeEvac...
         fail $ "Unsupported request: excluded nodes not equal to\
                \ instance's " ++  node_type ++ "(" ++ show exp_node
                ++ " versus " ++ show exndx ++ ")"
    (nl', il', esol) <- Evacuate.tryNodeEvac opts gl nl il reloc_type [idx]
    nodes <- case lookup idx (Evacuate.esFailed esol) of
               Just msg -> fail msg
               Nothing ->
                   case lookup idx (map (\(a, _, b) -> (a, b))
                                    (Evacuate.esMoved esol)) of
                     Nothing ->
                         fail "Internal error: lost instance idx during move"
                     Just n -> return n
    let inst = Container.find idx il'
        pnode = Instance.pNode inst
        snode = Instance.sNode inst
    nodes' <-
      case mir_type of
        MirrorNone -> fail "Internal error: mirror type none after relocation?!"
        MirrorInternal ->
          do
            when (snode == sorig) $
                 fail "Internal error: instance didn't change secondary node?!"
            when (snode == pnode) $
                 fail "Internal error: selected primary as new secondary?!"
            if nodes == [pnode, snode]
              then return [snode] -- only the new secondary is needed
              else fail $ "Internal error: inconsistent node list (" ++
                   show nodes ++ ") versus instance nodes (" ++ show pnode ++
                   "," ++ show snode ++ ")"
        MirrorExternal ->
          do
            when (pnode == porig) $
                 fail "Internal error: instance didn't change primary node?!"
            if nodes == [pnode]
              then return nodes
              else fail $ "Internal error: inconsistent node list (" ++
                   show nodes ++ ") versus instance node (" ++ show pnode ++ ")"
    return (nl', il', nodes')
  
  processRelocate _ _ _ _ _ reqn _ =
    fail $ "Exchange " ++ show reqn ++ " nodes mode is not implemented"
  
  formatRelocate :: (Node.List, Instance.List, [Ndx])
                 -> Result IAllocResult
  formatRelocate (nl, il, ndxs) =
    let nodes = map (`Container.find` nl) ndxs
        names = map Node.name nodes
    in Ok ("success", showJSON names, nl, il)
  
  -- | Process a request and return new node lists.
  processRequest :: AlgorithmOptions -> Request -> Result IAllocResult
  processRequest opts request =
    let Request rqtype (ClusterData gl nl il _ _) = request
    in case rqtype of
         Allocate xi (Cluster.AllocDetails reqn Nothing) rest_nodes ->
           let opts' = opts { algRestrictToNodes = algRestrictToNodes opts
                                                   `mplus` rest_nodes }
           in Cluster.tryMGAlloc opts' gl nl il xi reqn >>= formatAllocate il
         Allocate xi (Cluster.AllocDetails reqn (Just gn)) rest_nodes ->
           let opts' = opts { algRestrictToNodes = algRestrictToNodes opts
                                                   `mplus` rest_nodes }
           in Cluster.tryGroupAlloc opts' gl nl il gn xi reqn
              >>= formatAllocate il
         Relocate idx reqn exnodes ->
           processRelocate opts gl nl il idx reqn exnodes >>= formatRelocate
         ChangeGroup gdxs idxs ->
           Cluster.tryChangeGroup opts gl nl il idxs gdxs >>=
                  formatNodeEvac gl nl il
         NodeEvacuate xi mode ->
           Evacuate.tryNodeEvac opts gl nl il mode xi >>=
                  formatNodeEvac gl nl il
         MultiAllocate xies ->
           Cluster.allocList opts gl nl il xies [] >>= formatMultiAlloc
         AllocateSecondary xi ->
           AllocSecondary.tryAllocateSecondary opts gl nl il xi
             >>= formatAllocateSecondary il
  
  -- | Reads the request from the data file(s).
  readRequest :: FilePath -- ^ Path to IAllocator input file
              -> Int -- ^ Static node memory size, see optStaticKvmNodeMemory
              -> IO Request
  readRequest fp static_n_mem = do
    now <- getClockTime
    input_data <- case fp of
                    "-" -> getContents
                    _   -> readFile fp
    case parseData now input_data static_n_mem of
      Bad err -> exitErr err
      Ok (fix_msgs, rq) -> maybeShowWarnings fix_msgs >> return rq
  
  -- | Format an IAlloc result to maybe the new cluster and a response.
  formatIAllocResult :: Result IAllocResult
                     -> (Maybe (Node.List, Instance.List), String)
  formatIAllocResult iallocResult =
    let (ok, info, result, cdata) =
          case iallocResult of
            Ok (msg, r, nl, il) -> (True, "Request successful: " ++ msg, r,
                                    Just (nl, il))
            Bad msg -> (False, "Request failed: " ++ msg, JSArray [], Nothing)
        rstring = formatResponse ok info result
    in (cdata, rstring)
  
  -- | Main iallocator pipeline.
  runIAllocator :: AlgorithmOptions
                -> Request -> (Maybe (Node.List, Instance.List), String)
  runIAllocator opts request = formatIAllocResult $ processRequest opts request
  
  -- | Load the data from an iallocation request file
  loadData :: FilePath -- ^ Path to IAllocator input file
           -> Int -- ^ Static node memory size, see optStaticKvmNodeMemory
           -> IO (Result ClusterData)
  loadData fp static_n_mem = do
    Request _ cdata <- readRequest fp static_n_mem
    return $ Ok cdata
  