refactor: simplify logger middleware

src/PostgREST/Middleware.hs

@@ -6,7 +6,6 @@ Description : Sets CORS policy. Also the PostgreSQL GUCs, role, search_path and
 {-# LANGUAGE RecordWildCards #-}
 module PostgREST.Middleware
   ( runPgLocals
-  , pgrstFormat
   , pgrstMiddleware
   , optionalRollback
   ) where
@@ -24,21 +23,16 @@ import qualified Hasql.DynamicStatements.Snippet      as SQL hiding
 import qualified Hasql.DynamicStatements.Statement    as SQL
 import qualified Hasql.Transaction                    as SQL
 import qualified Network.Wai                          as Wai
-import qualified Network.Wai.Logger                   as Wai
 import qualified Network.Wai.Middleware.Cors          as Wai
-import qualified Network.Wai.Middleware.Gzip          as Wai
 import qualified Network.Wai.Middleware.RequestLogger as Wai
 
 import Control.Arrow ((***))
 
-import Data.Function             (id)
 import Data.List                 (lookup)
 import Data.Scientific           (FPFormat (..), formatScientific,
                                   isInteger)
-import Network.HTTP.Types.Status (Status, status400, status500,
-                                  statusCode)
+import Network.HTTP.Types.Status (status400, status500)
 import System.IO.Unsafe          (unsafePerformIO)
-import System.Log.FastLogger     (toLogStr)
 
 import PostgREST.Config             (AppConfig (..), LogLevel (..))
 import PostgREST.Config.PgVersion   (PgVersion (..), pgVersion140)
@@ -95,45 +89,23 @@ runPgLocals conf claims app req jsonDbS actualPgVersion = do
     unquoted (JSON.Bool b) = show b
     unquoted v = T.decodeUtf8 . LBS.toStrict $ JSON.encode v
 
--- | Log in apache format. Only requests that have a status greater than minStatus are logged.
--- | There's no way to filter logs in the apache format on wai-extra: https://hackage.haskell.org/package/wai-extra-3.0.29.2/docs/Network-Wai-Middleware-RequestLogger.html#t:OutputFormat.
--- | So here we copy wai-logger apacheLogStr function: https://github.com/kazu-yamamoto/logger/blob/a4f51b909a099c51af7a3f75cf16e19a06f9e257/wai-logger/Network/Wai/Logger/Apache.hs#L45
--- | TODO: Add the ability to filter apache logs on wai-extra and remove this function.
-pgrstFormat :: Status -> Wai.OutputFormatter
-pgrstFormat minStatus date req status responseSize =
-  if status < minStatus
-    then mempty
-  else toLogStr (getSourceFromSocket req)
-    <> " - - ["
-    <> toLogStr date
-    <> "] \""
-    <> toLogStr (Wai.requestMethod req)
-    <> " "
-    <> toLogStr (Wai.rawPathInfo req <> Wai.rawQueryString req)
-    <> " "
-    <> toLogStr (show (Wai.httpVersion req)::Text)
-    <> "\" "
-    <> toLogStr (show (statusCode status)::Text)
-    <> " "
-    <> toLogStr (maybe "-" show responseSize::Text)
-    <> " \""
-    <> toLogStr (fromMaybe mempty $ Wai.requestHeaderReferer req)
-    <> "\" \""
-    <> toLogStr (fromMaybe mempty $ Wai.requestHeaderUserAgent req)
-    <> "\"\n"
-  where
-    getSourceFromSocket = BS.pack . Wai.showSockAddr . Wai.remoteHost
-
-pgrstMiddleware :: LogLevel -> Wai.Application -> Wai.Application
+pgrstMiddleware :: LogLevel -> Wai.Middleware
 pgrstMiddleware logLevel =
-    logger
+    logger logLevel
   . Wai.cors corsPolicy
+
+logger :: LogLevel -> Wai.Middleware
+logger logLevel = case logLevel of
+  LogInfo  -> requestLogger (const True)
+  LogWarn  -> requestLogger (>= status400)
+  LogError -> requestLogger (>= status500)
+  LogCrit  -> requestLogger (const False)
   where
-    logger = case logLevel of
-      LogCrit  -> id
-      LogError -> unsafePerformIO $ Wai.mkRequestLogger Wai.def { Wai.outputFormat = Wai.CustomOutputFormat $ pgrstFormat status500}
-      LogWarn  -> unsafePerformIO $ Wai.mkRequestLogger Wai.def { Wai.outputFormat = Wai.CustomOutputFormat $ pgrstFormat status400}
-      LogInfo  -> Wai.logStdout
+    requestLogger filterStatus = unsafePerformIO $ Wai.mkRequestLogger Wai.defaultRequestLoggerSettings
+      { Wai.outputFormat = Wai.ApacheWithSettings $
+          Wai.defaultApacheSettings
+            & Wai.setApacheRequestFilter (\_ res -> filterStatus $ Wai.responseStatus res)
+      }
 
 -- | CORS policy to be used in by Wai Cors middleware
 corsPolicy :: Wai.Request -> Maybe Wai.CorsResourcePolicy