Initial support for reading from RAPI

src/Rapi.hs

+{-| Implementation of the RAPI client interface.
+
+-}
+
+module Rapi
+    where
+
+import Network.Curl
+import Network.Curl.Types
+import Network.Curl.Code
+import Data.Either (either)
+import Data.Maybe
+import Control.Monad
+import Text.JSON
+import Text.Printf (printf)
+import Utils
+
+
+{-- Our cheap monad-like stuff.
+
+Thi is needed since Either e a is already a monad instance somewhere
+in the standard libraries (Control.Monad.Error) and we don't need that
+entire thing.
+
+-}
+combine :: (Either String a) -> (a -> Either String b)  -> (Either String b)
+combine (Left s) _ = Left s
+combine (Right s) f = f s
+
+ensureList :: [Either String a] -> Either String [a]
+ensureList lst =
+    foldr (\elem accu ->
+               case (elem, accu) of
+                 (Left x, _) -> Left x
+                 (_, Left x) -> Left x -- should never happen
+                 (Right e, Right a) -> Right (e:a)
+          )
+    (Right []) lst
+
+loadJSArray :: String -> Either String [JSObject JSValue]
+loadJSArray s = resultToEither $ decodeStrict s
+
+getStringElement :: String -> JSObject JSValue -> Either String String
+getStringElement key o =
+    resultToEither $ valFromObj key o
+
+getIntElement :: String -> JSObject JSValue -> Either String String
+getIntElement key o =
+    let tmp = resultToEither $ ((valFromObj key o)::Result Int)
+    in case tmp of
+         Left x -> Left x
+         Right x -> Right $ show x
+
+concatElems a b =
+    case a of
+      Left _ -> a
+      Right [] -> b
+      Right x ->
+          case b of
+            Left _ -> b
+            Right y ->  Right (x ++ "|" ++ y)
+
+getUrl :: String -> IO (Either String String)
+getUrl url = do
+  (code, body) <- curlGetString url [CurlSSLVerifyPeer False,
+                                     CurlSSLVerifyHost 0]
+  return (case code of
+            CurlOK -> Right body
+            _ -> Left $ printf "url:%s, error: %s" url (show code))
+
+getInstances :: String -> IO (Either String String)
+getInstances master =
+    let url = printf "https://%s:5080/2/instances?bulk=1" master
+    in do
+      body <- getUrl  url
+      let inst = body `combine` loadJSArray `combine` (parseList parseInstance)
+      return inst
+
+getNodes :: String -> IO (Either String String)
+getNodes master =
+    let url = printf "https://%s:5080/2/nodes?bulk=1" master
+    in do
+      body <- getUrl  url
+      let inst = body `combine` loadJSArray `combine` (parseList parseNode)
+      return inst
+
+parseList :: (JSObject JSValue -> Either String String)
+          -> [JSObject JSValue]
+          ->Either String String
+parseList fn idata =
+    let ml = ensureList $ map fn idata
+    in ml `combine` (Right . unlines)
+
+parseInstance :: JSObject JSValue -> Either String String
+parseInstance a =
+    let name = getStringElement "name" a
+        disk = case getIntElement "disk_usage" a of
+                 Left _ -> getIntElement "sda_size" a
+                 Right x -> Right x
+        bep = (resultToEither $ valFromObj "beparams" a)
+    in
+      case bep of
+        Left x -> Left x
+        Right x -> let mem = getIntElement "memory" x
+                   in concatElems name $ concatElems mem disk
+
+parseNode :: JSObject JSValue -> Either String String
+parseNode a =
+    let name = getStringElement "name" a
+        mtotal = getIntElement "mtotal" a
+        mfree = getIntElement "mfree" a
+        dtotal = getIntElement "dtotal" a
+        dfree = getIntElement "dfree" a
+    in concatElems name $ concatElems mtotal $ concatElems mfree $
+       concatElems dtotal dfree

src/hbal.hs

@@ -16,6 +16,7 @@ import Text.Printf (printf)
 
 import qualified Container
 import qualified Cluster
+import Rapi
 
 -- | Command line options structure.
 data Options = Options
@@ -110,6 +111,10 @@ parseOpts argv =
 -- | Main function.
 main :: IO ()
 main = do
+  i <- getInstances "gnta1"
+  n <- getNodes "gnta1"
+  print i
+  print n
   cmd_args <- System.getArgs
   (opts, _) <- parseOpts cmd_args
   (nl, il, ktn, kti) <- liftM2 Cluster.loadData