Merge pull request #1 from fretlink/support-additional-metav2019-01-15

Support additional meta in GELF messages

1 files changed, 43 insertions, 6 deletions

diff --git a/src/Graylog/Gelf.hs b/src/Graylog/Gelf.hs
index ee17e3d..8ffe24f 100644
--- a/src/Graylog/Gelf.hs
+++ b/src/Graylog/Gelf.hs
@@ -1,17 +1,21 @@
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE DeriveGeneric      #-}
 {-# LANGUAGE OverloadedStrings  #-}
+{-# LANGUAGE RecordWildCards    #-}
 
 -- | Default formatting for Graylog messages,
 -- see http://docs.graylog.org/en/latest/pages/gelf.html
 module Graylog.Gelf where
 
-import           Data.Aeson        (ToJSON (..), Value (..), genericToJSON,
-                                    toJSON)
-import           Data.Aeson.Casing
-import           Data.Text         (Text)
+import           Data.Aeson          (ToJSON (..), Value (..), object, toJSON,
+                                      (.=))
+import           Data.HashMap.Strict (HashMap)
+import           Data.Scientific     (Scientific)
+import           Data.Semigroup      ((<>))
+import           Data.Text           (Text)
 import           Data.Time
 import           Data.Typeable
+import           GHC.Exts            (toList)
 import           GHC.Generics
 
 data GELF
@@ -24,11 +28,44 @@ data GELF
       , _gelfLevel        :: Maybe SyslogLevel
       , _gelfLine         :: Maybe Word
       , _gelfFile         :: Maybe Text
+      , _gelfMeta         :: HashMap Text MetaValue
       }
    deriving (Show, Typeable, Generic)
 
+data MetaValue
+  = TextValue Text
+  | NumberValue Scientific
+  deriving (Show)
+
+instance ToJSON MetaValue where
+  toJSON (TextValue txt) = toJSON txt
+  toJSON (NumberValue n) = toJSON n
+
+class ToMeta a where
+  toMeta :: a -> MetaValue
+
+instance ToMeta Text where
+  toMeta = TextValue
+
+instance ToMeta Scientific where
+  toMeta = NumberValue
+
+instance ToMeta Integer where
+  toMeta = NumberValue . fromInteger
+
+instance ToMeta Int where
+  toMeta = toMeta . toInteger
+
 instance ToJSON GELF where
-   toJSON = genericToJSON $ aesonPrefix snakeCase
+  toJSON GELF{..} = object $ [ "version"        .= _gelfVersion
+                             , "host"           .= _gelfHost
+                             , "short_message"  .= _gelfShortMessage
+                             , "full_message"   .= _gelfFullMessage
+                             , "timestamp"      .= _gelfTimestamp
+                             , "level"          .= _gelfLevel
+                             , "line"           .= _gelfLine
+                             , "file"           .= _gelfFile
+                             ] <> toList (toJSON <$> _gelfMeta)
 
 --
 
@@ -69,4 +106,4 @@ simpleGelf
    -> Text     -- ^ Short message
    -> GELF
 simpleGelf host short =
-   GELF Version1x1 host short Nothing Nothing Nothing Nothing Nothing
+  GELF Version1x1 host short Nothing Nothing Nothing Nothing Nothing mempty