no systemd on macos (or any other non-linux os)

Fixes #6

backend/Rhyolite/Backend/Logging.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP #-}
 {-# LANGUAGE DeriveAnyClass #-}
 {-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE DeriveTraversable #-}
@@ -41,7 +42,9 @@ module Rhyolite.Backend.Logging
   , RhyoliteLogLevel(..)
   , RhyoliteLogAppenderStderr (..)
   , RhyoliteLogAppenderFile (..)
+#ifdef linux_HOST_OS
   , RhyoliteLogAppenderJournald (..)
+#endif
   , example
   ) where
 
@@ -63,7 +66,11 @@ import qualified Data.Text.Encoding as TE
 import qualified Data.Trie.BigEndianPatricia.Base as Trie
 import GHC.Generics
 import System.Log.FastLogger
+
+#ifdef linux_HOST_OS
 import Systemd.Journal
+#endif
+
 import Data.Default
 
 newtype LoggingEnv =  LoggingEnv { unLoggingEnv :: Loc -> LogSource -> LogLevel -> LogStr -> IO () }
@@ -105,7 +112,9 @@ data LoggingContext m = LoggingContext
 data RhyoliteLogAppender
    = RhyoliteLogAppender_Stderr   RhyoliteLogAppenderStderr
    | RhyoliteLogAppender_File     RhyoliteLogAppenderFile
-   | RhyoliteLogAppender_Journald RhyoliteLogAppenderJournald
+#ifdef linux_HOST_OS
+   | RhyoliteLogAppender_Journald RhyoliteLogAppenderJournald -- journalctl log with syslogIdentifier specified.
+#endif
   deriving (Generic, Eq, Ord, Show)
 
 instance Default RhyoliteLogAppender where
@@ -122,9 +131,11 @@ data RhyoliteLogAppenderFile = RhyoliteLogAppenderFile
   { _rhyoliteLogAppenderFile_file :: !FilePath
   } deriving (Generic, Eq, Ord, Show)
 
+#ifdef linux_HOST_OS
 data RhyoliteLogAppenderJournald = RhyoliteLogAppenderJournald
   { _rhyoliteLogAppenderJournald_syslogIdentifier :: T.Text -- journalctl log with syslogIdentifier specified.
   } deriving (Generic, Eq, Ord, Show)
+#endif
 
 -- derive a little differently from `Rhyolite.Request.makeJson` so that more
 -- things end up as records, so that new fields don't break old configs
@@ -138,7 +149,9 @@ fmap concat $ traverse (deriveJSON defaultOptions
   , ''RhyoliteLogAppender
   , ''RhyoliteLogAppenderStderr
   , ''RhyoliteLogAppenderFile
+#ifdef linux_HOST_OS
   , ''RhyoliteLogAppenderJournald
+#endif
   , ''LoggingConfig
   ]
 
@@ -148,6 +161,7 @@ runLoggingEnv = flip runLoggingT . unLoggingEnv
 logToFastLogger :: LoggerSet -> LoggingEnv
 logToFastLogger ls = LoggingEnv $ \_loc logSource logLevel logStr -> pushLogStrLn ls (toLogStr (show logLevel) <> toLogStr (show logSource) <> logStr)
 
+#ifdef linux_HOST_OS
 logger2journald :: LogLevel -> JournalFields
 logger2journald = \case
   LevelWarn -> priority Warning
@@ -156,6 +170,7 @@ logger2journald = \case
   LevelError -> priority Error
   LevelOther level -> priority Error  -- Error because that makes this logger2journald monotone
     <> mkJournalField' "PRIORITY_OTHER" level
+#endif
 
 class LogAppender a where
   getLogContext :: MonadIO m => a -> m (LoggingContext m)
@@ -168,14 +183,16 @@ instance LogAppender RhyoliteLogAppender where
       RhyoliteLogAppender_File (RhyoliteLogAppenderFile filename) -> do
         logSet <- liftIO $ newFileLoggerSet defaultBufSize filename
         return $ LoggingContext (liftIO (rmLoggerSet logSet)) (logToFastLogger logSet)
+#ifdef linux_HOST_OS
       RhyoliteLogAppender_Journald cfg -> return $ LoggingContext (return ()) (logToJournalCtl (syslogIdentifier $ _rhyoliteLogAppenderJournald_syslogIdentifier cfg))
-
+#endif
 
 configLogger :: (LogAppender a, MonadIO m) => LoggingConfig a -> m (LoggingContext m)
 configLogger (LoggingConfig ls fs) = do
   LoggingContext cleaner logger <- getLogContext ls
   return $ LoggingContext cleaner $ filterLog (fmap toLogLevel $ maybe M.empty id fs) logger
 
+#ifdef linux_HOST_OS
 mkJournalField' :: T.Text -> T.Text -> JournalFields
 mkJournalField' k v = HashMap.singleton (mkJournalField k) (TE.encodeUtf8 v)
 
@@ -193,6 +210,7 @@ logToJournalCtl syslogId = LoggingEnv $ \loc logSource logLevel logStr -> sendMe
   , loc2jf loc
   , mkJournalField' "logsource" logSource
   ]
+#endif
 
 -- | match the LogSource on prefixes in m.  if found, log only the messages at equal or higher than the
 --   matched level.  if not found, log only LevelWarn or higher.   You can override the default with a zero length prefix, ie `"" := LevelDebug`
@@ -224,7 +242,9 @@ example f = do
     [ LoggingConfig (RhyoliteLogAppender_Stderr $ RhyoliteLogAppenderStderr Nothing) Nothing
     , LoggingConfig (RhyoliteLogAppender_File $ RhyoliteLogAppenderFile "/dev/null") Nothing
     , LoggingConfig (RhyoliteLogAppender_Stderr $ RhyoliteLogAppenderStderr Nothing) (Just $ M.fromList [("context",RhyoliteLogLevel_Debug)])
+#ifdef linux_HOST_OS
     , LoggingConfig (RhyoliteLogAppender_Journald $ RhyoliteLogAppenderJournald "foo") Nothing
+#endif
     ]
   withLogging @ RhyoliteLogAppender [def] $ do
     $(logError) "Err"

backend/rhyolite-backend.cabal

@@ -30,7 +30,6 @@ library
     , HaskellNet-SSL
     , io-streams
     , lens
-    , libsystemd-journal
     , lifted-base
     , mime-mail
     , monad-control
@@ -60,6 +59,9 @@ library
     , vector
     , websockets
     , websockets-snap
+  if os(linux)
+    build-depends:
+      libsystemd-journal
 
   exposed-modules:
     Rhyolite.Backend.Account