src/Graylog/UDP.hs

   1 module Graylog.UDP
   2    ( sendLog
   3
   4    , module Export
   5    ) where
   6
   7 import           Data.Aeson
   8 import           Data.ByteString.Builder
   9 import qualified Data.ByteString.Lazy           as LBS
  10 import           Data.Monoid
  11 import           Data.Word
  12 import           Network.Socket.ByteString.Lazy
  13 import           System.Random
  14
  15 import           Graylog.Gelf                   as Export
  16 import           Graylog.Types                  as Export
  17
  18 sendLog :: Graylog -> GELF -> IO ()
  19 sendLog glog msg = do
  20    cks <- chunky glog raw
  21    mapM_ (send $ _graylogSocket glog) cks
  22    where
  23       raw = encode msg
  24
  25 chunky :: Graylog -> LBS.ByteString -> IO [LBS.ByteString]
  26 chunky glog raw = do
  27    groupId <- randomIO
  28    let groups = divide totalNum raw
  29    return $ append groupId groups seqNums
  30    where
  31       magic           = word8 0x1e <> word8 0x0f
  32       seqNums         = [0..] :: [Word8]
  33       totalNum        = if excess > 0 then count + 1 else count
  34       (count, excess) = quotRem (LBS.length raw) gsize
  35       hlen            = 12
  36       gsize           = (fromIntegral (_graylogChunkSize glog)) - hlen
  37
  38       divide   0 dat = [dat]
  39       divide num dat = let (pre, post) = LBS.splitAt gsize dat
  40                         in pre : divide (num - 1) post
  41
  42       append _   []     _      = []
  43       append _   _      []     = error "the impossible has happened."
  44       append gid (g:gs) (s:ss) = (toLazyByteString
  45          $ magic
  46         <> word64BE gid
  47         <> word8 s
  48         <> word8 (fromIntegral totalNum)
  49         <> lazyByteString g) : append gid gs ss