root / Ganeti / HTools / IAlloc.hs @ 9188aeef
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{-| Implementation of the iallocator interface. |
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-} |
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module Ganeti.HTools.IAlloc |
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( |
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parseData |
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, formatResponse |
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, RqType(..) |
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, Request(..) |
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) where |
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|
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import Data.Either () |
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import Control.Monad |
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import Text.JSON (JSObject, JSValue(JSBool, JSString, JSArray), |
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makeObj, encodeStrict, decodeStrict, |
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fromJSObject, toJSString) |
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import qualified Ganeti.HTools.Container as Container |
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import qualified Ganeti.HTools.Node as Node |
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import qualified Ganeti.HTools.Instance as Instance |
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import Ganeti.HTools.Loader |
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import Ganeti.HTools.Utils |
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import Ganeti.HTools.Types |
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|
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-- | The request type. |
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data RqType |
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= Allocate Instance.Instance Int -- ^ A new instance allocation |
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| Relocate Idx Int [Ndx] -- ^ Move an instance to a new |
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-- secondary node |
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deriving (Show) |
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|
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-- | A complete request, as received from Ganeti. |
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data Request = Request RqType Node.List Instance.List String |
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deriving (Show) |
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|
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-- | Parse the basic specifications of an instance. |
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-- |
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-- Instances in the cluster instance list and the instance in an |
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-- 'Allocate' request share some common properties, which are read by |
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-- this function. |
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parseBaseInstance :: String |
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-> JSObject JSValue |
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-> Result (String, Instance.Instance) |
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parseBaseInstance n a = do |
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disk <- case fromObj "disk_usage" a of |
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Bad _ -> do |
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all_d <- fromObj "disks" a >>= asObjectList |
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szd <- mapM (fromObj "size") all_d |
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let sze = map (+128) szd |
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szf = (sum sze)::Int |
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return szf |
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x@(Ok _) -> x |
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mem <- fromObj "memory" a |
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let running = "running" |
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return $ (n, Instance.create n mem disk running 0 0) |
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|
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-- | Parses an instance as found in the cluster instance list. |
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parseInstance :: NameAssoc -- ^ The node name-to-index association list |
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-> String -- ^ The name of the instance |
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-> JSObject JSValue -- ^ The JSON object |
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-> Result (String, Instance.Instance) |
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parseInstance ktn n a = do |
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base <- parseBaseInstance n a |
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nodes <- fromObj "nodes" a |
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pnode <- readEitherString $ head nodes |
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pidx <- lookupNode ktn n pnode |
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let snodes = tail nodes |
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sidx <- (if null snodes then return Node.noSecondary |
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else (readEitherString $ head snodes) >>= lookupNode ktn n) |
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return (n, Instance.setBoth (snd base) pidx sidx) |
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|
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-- | Parses a node as found in the cluster node list. |
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parseNode :: String -- ^ The node's name |
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-> JSObject JSValue -- ^ The JSON object |
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-> Result (String, Node.Node) |
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parseNode n a = do |
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let name = n |
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offline <- fromObj "offline" a |
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drained <- fromObj "drained" a |
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node <- (case offline of |
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True -> return $ Node.create name 0 0 0 0 0 True |
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_ -> do |
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mtotal <- fromObj "total_memory" a |
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mnode <- fromObj "reserved_memory" a |
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mfree <- fromObj "free_memory" a |
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dtotal <- fromObj "total_disk" a |
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dfree <- fromObj "free_disk" a |
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return $ Node.create n mtotal mnode mfree |
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dtotal dfree (offline || drained)) |
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return (name, node) |
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|
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-- | Top-level parser. |
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parseData :: String -- ^ The JSON message as received from Ganeti |
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-> Result Request -- ^ A (possible valid) request |
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parseData body = do |
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decoded <- fromJResult $ decodeStrict body |
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let obj = decoded |
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-- request parser |
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request <- fromObj "request" obj |
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rname <- fromObj "name" request |
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-- existing node parsing |
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nlist <- fromObj "nodes" obj |
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let ndata = fromJSObject nlist |
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nobj <- (mapM (\(x,y) -> asJSObject y >>= parseNode x)) ndata |
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let (ktn, nl) = assignIndices nobj |
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-- existing instance parsing |
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ilist <- fromObj "instances" obj |
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let idata = fromJSObject ilist |
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iobj <- (mapM (\(x,y) -> asJSObject y >>= parseInstance ktn x)) idata |
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let (kti, il) = assignIndices iobj |
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(map_n, map_i, csf) <- mergeData (nl, il) |
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req_nodes <- fromObj "required_nodes" request |
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optype <- fromObj "type" request |
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rqtype <- |
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case optype of |
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"allocate" -> |
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do |
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inew <- parseBaseInstance rname request |
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let io = snd inew |
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return $ Allocate io req_nodes |
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"relocate" -> |
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do |
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ridx <- lookupInstance kti rname |
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ex_nodes <- fromObj "relocate_from" request |
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let ex_nodes' = map (stripSuffix $ length csf) ex_nodes |
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ex_idex <- mapM (Container.findByName map_n) ex_nodes' |
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return $ Relocate ridx req_nodes ex_idex |
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other -> fail $ ("Invalid request type '" ++ other ++ "'") |
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return $ Request rqtype map_n map_i csf |
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|
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-- | Formats the response into a valid IAllocator response message. |
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formatResponse :: Bool -- ^ Whether the request was successful |
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-> String -- ^ Information text |
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-> [String] -- ^ The list of chosen nodes |
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-> String -- ^ The JSON-formatted message |
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formatResponse success info nodes = |
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let |
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e_success = ("success", JSBool success) |
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e_info = ("info", JSString . toJSString $ info) |
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e_nodes = ("nodes", JSArray $ map (JSString . toJSString) nodes) |
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in encodeStrict $ makeObj [e_success, e_info, e_nodes] |