Synnefo » snf-ganeti

{-| Generic data loader

This module holds the common code for parsing the input data after it

has been loaded from external sources.

-}

{-

Copyright (C) 2009 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.Loader

    ( mergeData

    , checkData

    , assignIndices

    , lookupNode

    , lookupInstance

    , stripSuffix

    , RqType(..)

    , Request(..)

    ) where

import Data.Function (on)

import Data.List

import Data.Maybe (fromJust)

import Text.Printf (printf)

import qualified Ganeti.HTools.Container as Container

import qualified Ganeti.HTools.Instance as Instance

import qualified Ganeti.HTools.Node as Node

import Ganeti.HTools.Types

-- * Constants

-- | The exclusion tag prefix

exTagsPrefix :: String

exTagsPrefix = "htools:iextags:"

-- * Types

{-| The iallocator request type.

This type denotes what request we got from Ganeti and also holds

request-specific fields.

-}

data RqType

    = Allocate Instance.Instance Int -- ^ A new instance allocation

    | Relocate Idx Int [Ndx]         -- ^ Move an instance to a new

                                     -- secondary node

    | Evacuate [Ndx]                 -- ^ Evacuate nodes

    deriving (Show)

-- | A complete request, as received from Ganeti.

data Request = Request RqType Node.List Instance.List [String] String

    deriving (Show)

-- * Functions

-- | Lookups a node into an assoc list.

lookupNode :: (Monad m) => [(String, Ndx)] -> String -> String -> m Ndx

lookupNode ktn inst node =

    case lookup node ktn of

      Nothing -> fail $ "Unknown node '" ++ node ++ "' for instance " ++ inst

      Just idx -> return idx

-- | Lookups an instance into an assoc list.

lookupInstance :: (Monad m) => [(String, Idx)] -> String -> m Idx

lookupInstance kti inst =

    case lookup inst kti of

      Nothing -> fail $ "Unknown instance '" ++ inst ++ "'"

      Just idx -> return idx

-- | Given a list of elements (and their names), assign indices to them.

assignIndices :: (Element a) =>

                 [(String, a)]

              -> (NameAssoc, [(Int, a)])

assignIndices =

    unzip . map (\ (idx, (k, v)) -> ((k, idx), (idx, setIdx v idx)))

          . zip [0..]

-- | Assoc element comparator

assocEqual :: (Eq a) => (a, b) -> (a, b) -> Bool

assocEqual = (==) `on` fst

-- | For each instance, add its index to its primary and secondary nodes.

fixNodes :: [(Ndx, Node.Node)]

         -> Instance.Instance

         -> [(Ndx, Node.Node)]

fixNodes accu inst =

    let

        pdx = Instance.pNode inst

        sdx = Instance.sNode inst

        pold = fromJust $ lookup pdx accu

        pnew = Node.setPri pold inst

        ac1 = deleteBy assocEqual (pdx, pold) accu

        ac2 = (pdx, pnew):ac1

    in

      if sdx /= Node.noSecondary

      then let sold = fromJust $ lookup sdx accu

               snew = Node.setSec sold inst

               ac3 = deleteBy assocEqual (sdx, sold) ac2

           in (sdx, snew):ac3

      else ac2

-- | Remove non-selected tags from the exclusion list

filterExTags :: [String] -> Instance.Instance -> Instance.Instance

filterExTags tl inst =

    let old_tags = Instance.tags inst

        new_tags = filter (\tag -> any (\extag -> isPrefixOf extag tag) tl)

                   old_tags

    in inst { Instance.tags = new_tags }

-- | Compute the longest common suffix of a list of strings that

-- | starts with a dot.

longestDomain :: [String] -> String

longestDomain [] = ""

longestDomain (x:xs) =

      foldr (\ suffix accu -> if all (isSuffixOf suffix) xs

                              then suffix

                              else accu)

      "" $ filter (isPrefixOf ".") (tails x)

-- | Remove tail suffix from a string.

stripSuffix :: Int -> String -> String

stripSuffix sflen name = take (length name - sflen) name

-- | Extracts the exclusion tags from the cluster configuration

extractExTags :: [String] -> [String]

extractExTags =

    map (drop (length exTagsPrefix)) .

    filter (isPrefixOf exTagsPrefix)

-- | Initializer function that loads the data from a node and instance

-- list and massages it into the correct format.

mergeData :: [(String, DynUtil)]  -- ^ Instance utilisation data

          -> [String]             -- ^ Exclusion tags

          -> (Node.AssocList, Instance.AssocList, [String])

          -- ^ Data from backends

          -> Result (Node.List, Instance.List, [String], String)

mergeData um extags (nl, il, tags) =

  let il2 = Container.fromAssocList il

      il3 = foldl' (\im (name, n_util) ->

                        case Container.findByName im name of

                          Nothing -> im -- skipping unknown instance

                          Just inst ->

                              let new_i = inst { Instance.util = n_util }

                              in Container.add (Instance.idx inst) new_i im

                   ) il2 um

      allextags = extags ++ extractExTags tags

      il4 = Container.map (filterExTags allextags) il3

      nl2 = foldl' fixNodes nl (Container.elems il4)

      nl3 = Container.fromAssocList

            (map (\ (k, v) -> (k, Node.buildPeers v il4)) nl2)

      node_names = map (Node.name . snd) nl

      inst_names = map (Instance.name . snd) il

      common_suffix = longestDomain (node_names ++ inst_names)

      csl = length common_suffix

      snl = Container.map (\n -> setName n (stripSuffix csl $ nameOf n)) nl3

      sil = Container.map (\i -> setName i (stripSuffix csl $ nameOf i)) il4

  in Ok (snl, sil, tags, common_suffix)

-- | Checks the cluster data for consistency.

checkData :: Node.List -> Instance.List

          -> ([String], Node.List)

checkData nl il =

    Container.mapAccum

        (\ msgs node ->

             let nname = Node.name node

                 nilst = map (flip Container.find il) (Node.pList node)

                 dilst = filter (not . Instance.running) nilst

                 adj_mem = sum . map Instance.mem $ dilst

                 delta_mem = truncate (Node.tMem node)

                             - Node.nMem node

                             - Node.fMem node

                             - nodeImem node il

                             + adj_mem

                 delta_dsk = truncate (Node.tDsk node)

                             - Node.fDsk node

                             - nodeIdsk node il

                 newn = Node.setFmem (Node.setXmem node delta_mem)

                        (Node.fMem node - adj_mem)

                 umsg1 = [printf "node %s is missing %d MB ram \

                                 \and %d GB disk"

                                 nname delta_mem (delta_dsk `div` 1024) |

                                 delta_mem > 512 || delta_dsk > 1024]::[String]

             in (msgs ++ umsg1, newn)

        ) [] nl

-- | Compute the amount of memory used by primary instances on a node.

nodeImem :: Node.Node -> Instance.List -> Int

nodeImem node il =

    let rfind = flip Container.find il

    in sum . map (Instance.mem . rfind)

           $ Node.pList node

-- | Compute the amount of disk used by instances on a node (either primary

-- or secondary).

nodeIdsk :: Node.Node -> Instance.List -> Int

nodeIdsk node il =

    let rfind = flip Container.find il

    in sum . map (Instance.dsk . rfind)

           $ Node.pList node ++ Node.sList node