htools: add a very basic lib/config.py equivalent

This only is able to load the configuration data for now.

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Guido Trotter <ultrotter@google.com>

Makefile.am

@@ -395,6 +395,7 @@ HS_LIB_SRCS = \
 	htools/Ganeti/HTools/Program/Hscan.hs \
 	htools/Ganeti/HTools/Program/Hspace.hs \
 	htools/Ganeti/BasicTypes.hs \
+	htools/Ganeti/Config.hs \
 	htools/Ganeti/Jobs.hs \
 	htools/Ganeti/Luxi.hs \
 	htools/Ganeti/Objects.hs \

htools/Ganeti/Config.hs

+{-| Implementation of the Ganeti configuration database.
+
+-}
+
+{-
+
+Copyright (C) 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.Config
+    ( LinkIpMap
+    , loadConfig
+    , getNodeInstances
+    , getDefaultNicLink
+    , getInstancesIpByLink
+    , getNode
+    , getInstance
+    , getInstPrimaryNode
+    , buildLinkIpInstnameMap
+    ) where
+
+import Data.List (foldl')
+import qualified Data.Map as M
+import qualified Text.JSON as J
+
+import Ganeti.HTools.JSON
+import Ganeti.BasicTypes
+
+import qualified Ganeti.Constants as C
+import Ganeti.Objects
+
+-- | Type alias for the link and ip map.
+type LinkIpMap = M.Map String (M.Map String String)
+
+-- | Reads the config file.
+readConfig :: FilePath -> IO String
+readConfig = readFile
+
+-- | Parses the configuration file.
+parseConfig :: String -> Result ConfigData
+parseConfig = fromJResult "parsing configuration" . J.decodeStrict
+
+-- | Wrapper over 'readConfig' and 'parseConfig'.
+loadConfig :: FilePath -> IO (Result ConfigData)
+loadConfig = fmap parseConfig . readConfig
+
+-- * Query functions
+
+-- | Get instances of a given node.
+getNodeInstances :: ConfigData -> String -> ([Instance], [Instance])
+getNodeInstances cfg nname =
+    let all_inst = M.elems . configInstances $ cfg
+        pri_inst = filter ((== nname) . instPrimaryNode) all_inst
+        -- FIXME: actually compute the secondary nodes
+        sec_inst = undefined
+    in (pri_inst, sec_inst)
+
+-- | Returns the default cluster link.
+getDefaultNicLink :: ConfigData -> String
+getDefaultNicLink =
+  nicpLink . (M.! C.ppDefault) . clusterNicparams . configCluster
+
+-- | Returns instances of a given link.
+getInstancesIpByLink :: LinkIpMap -> String -> [String]
+getInstancesIpByLink linkipmap link =
+  M.keys $ M.findWithDefault M.empty link linkipmap
+
+-- | Looks up a node.
+getNode :: ConfigData -> String -> Result Node
+getNode cfg name =
+  maybe (Bad $ "Node " ++ name ++ " not found") Ok $
+        M.lookup name (configNodes cfg)
+
+-- | Looks up an instance.
+getInstance :: ConfigData -> String -> Result Instance
+getInstance cfg name =
+  maybe (Bad $ "Instance " ++ name ++ " not found") Ok $
+        M.lookup name (configInstances cfg)
+
+-- | Looks up an instance's primary node.
+getInstPrimaryNode :: ConfigData -> String -> Result Node
+getInstPrimaryNode cfg name =
+  getInstance cfg name >>= return . instPrimaryNode >>= getNode cfg
+
+-- | Builds link -> ip -> instname map.
+--
+-- TODO: improve this by splitting it into multiple independent functions:
+--
+-- * abstract the \"fetch instance with filled params\" functionality
+--
+-- * abstsract the [instance] -> [(nic, instance_name)] part
+--
+-- * etc.
+buildLinkIpInstnameMap :: ConfigData -> LinkIpMap
+buildLinkIpInstnameMap cfg =
+  let cluster = configCluster cfg
+      instances = M.elems . configInstances $ cfg
+      defparams = (M.!) (clusterNicparams cluster) C.ppDefault
+      nics = concatMap (\i -> [(instName i, nic) | nic <- instNics i])
+             instances
+  in foldl' (\accum (iname, nic) ->
+               let pparams = nicNicparams nic
+                   fparams = fillNICParams defparams pparams
+                   link = nicpLink fparams
+               in case nicIp nic of
+                    Nothing -> accum
+                    Just ip -> let oldipmap = M.findWithDefault (M.empty)
+                                              link accum
+                                   newipmap = M.insert ip iname oldipmap
+                               in M.insert link newipmap accum
+            ) M.empty nics