Synnefo » snf-ganeti

{-# LANGUAGE OverloadedStrings #-}

{-| Implementation of the Ganeti confd server functionality.

-}

{-

Copyright (C) 2013 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.Monitoring.Server

  ( main

  , checkMain

  , prepMain

  ) where

import Control.Applicative

import Control.Monad

import Snap.Core

import Snap.Http.Server

import Data.ByteString.Char8

import qualified Text.JSON as J

import Ganeti.Daemon

import qualified Ganeti.Constants as C

-- * Types and constants definitions

-- | Type alias for checkMain results.

type CheckResult = ()

-- | Type alias for prepMain results.

type PrepResult = Config Snap ()

-- | Version of the latest supported http API.

latestAPIVersion :: Int

latestAPIVersion = 1

-- * Configuration handling

-- | The default configuration for the HTTP server.

defaultHttpConf :: Config Snap ()

defaultHttpConf =

  setAccessLog (ConfigFileLog C.daemonsExtraLogfilesGanetiMondAccess) .

  setCompression False .

  setErrorLog (ConfigFileLog C.daemonsExtraLogfilesGanetiMondError) $

  setVerbose False

  emptyConfig

-- * Helper functions

-- | Check function for the monitoring agent.

checkMain :: CheckFn CheckResult

checkMain _ = return $ Right ()

-- | Prepare function for monitoring agent.

prepMain :: PrepFn CheckResult PrepResult

prepMain opts _ =

  return $

    setPort (maybe C.defaultMondPort fromIntegral (optPort opts))

      defaultHttpConf

-- * Query answers

-- | Reply to the supported API version numbers query.

versionQ :: Snap ()

versionQ = writeBS . pack $ J.encode [latestAPIVersion]

-- | Version 1 of the monitoring HTTP API.

version1Api :: Snap ()

version1Api =

  let returnNull = writeBS . pack $ J.encode J.JSNull :: Snap ()

  in ifTop returnNull <|>

     route

       [ ("list", listHandler)

       , ("report", reportHandler)

       ]

-- | Handler for returning lists.

listHandler :: Snap ()

listHandler =

  dir "collectors" $ writeText "TODO: return the list of collectors"

-- | Handler for returning data collector reports.

reportHandler :: Snap ()

reportHandler =

  route

    [ ("all", allReports)

    , (":category/:collector", oneReport)

    ]

-- | Return the report of all the available collectors

allReports :: Snap ()

allReports = writeText "TODO: return the reports of all the collectors"

-- | Return the report of one collector

oneReport :: Snap ()

oneReport = do

  category <- fmap (maybe mzero unpack) $ getParam "category"

  collector <- fmap (maybe mzero unpack) $ getParam "collector"

  writeBS . pack $

    "TODO: return the report for collector " ++ category

      ++ "/" ++ collector

-- | The function implementing the HTTP API of the monitoring agent.

-- TODO: Currently it only replies to the API version query: implement all the

-- missing features.

monitoringApi :: Snap ()

monitoringApi =

  ifTop versionQ <|>

  dir "1" version1Api

-- | Main function.

main :: MainFn CheckResult PrepResult

main _ _ httpConf =

  httpServe httpConf $ method GET monitoringApi