From d7dc6a493f3a2dd77eaeb40715622a9d06b61052 Mon Sep 17 00:00:00 2001
From: Wolfgang Walther <walther@technowledgy.de>
Date: Sun, 3 Jan 2021 22:28:47 +0100
Subject: [PATCH] refactor: simplify logger middleware

---
 postgrest.cabal             |  2 --
 src/PostgREST/Middleware.hs | 58 +++++++++----------------------------
 2 files changed, 14 insertions(+), 46 deletions(-)

diff --git a/postgrest.cabal b/postgrest.cabal
index 4711fd48dc5..ccec2fd8211 100644
--- a/postgrest.cabal
+++ b/postgrest.cabal
@@ -81,7 +81,6 @@ library
                     , contravariant-extras      >= 0.3.3 && < 0.4
                     , cookie                    >= 0.4.2 && < 0.5
                     , either                    >= 4.4.1 && < 5.1
-                    , fast-logger               >= 2.4.5
                     , gitrev                    >= 1.2 && < 1.4
                     , hasql                     >= 1.4 && < 1.5
                     , hasql-dynamic-statements  == 0.3.1
@@ -111,7 +110,6 @@ library
                     , wai                       >= 3.2.1 && < 3.3
                     , wai-cors                  >= 0.2.5 && < 0.3
                     , wai-extra                 >= 3.0.19 && < 3.2
-                    , wai-logger                >= 2.3.2
                     , wai-middleware-static     >= 0.8.1 && < 0.10
                     , warp                      >= 3.2.12 && < 3.4
                       -- -fno-spec-constr may help keep compile time memory use in check,
diff --git a/src/PostgREST/Middleware.hs b/src/PostgREST/Middleware.hs
index 8a794b03ac7..2b24126e256 100644
--- a/src/PostgREST/Middleware.hs
+++ b/src/PostgREST/Middleware.hs
@@ -5,7 +5,6 @@ Description : Sets CORS policy. Also the PostgreSQL GUCs, role, search_path and
 {-# LANGUAGE RecordWildCards #-}
 module PostgREST.Middleware
   ( runPgLocals
-  , pgrstFormat
   , pgrstMiddleware
   , optionalRollback
   ) where
@@ -23,21 +22,15 @@ import qualified Hasql.DynamicStatements.Statement    as H
 import qualified Hasql.Transaction                    as H
 import qualified Network.HTTP.Types.Header            as HTTP
 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 System.IO.Unsafe          (unsafePerformIO)
-import System.Log.FastLogger     (toLogStr)
+import Network.HTTP.Types.Status (status400, status500)
 
 import PostgREST.Config             (AppConfig (..), LogLevel (..))
 import PostgREST.Config.PgVersion   (PgVersion (..), pgVersion140)
@@ -95,45 +88,22 @@ runPgLocals conf claims app req jsonDbS actualPgVersion = do
     unquoted (JSON.Bool b) = show b
     unquoted v = toS $ 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 logLevel
   . Wai.cors corsPolicy
-  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
+
+logger :: LogLevel -> Wai.Middleware
+logger logLevel app req sendResponse = app req $ \res ->
+  let
+    status = Wai.responseStatus res
+    logRequest = Wai.logStdout app req sendResponse
+  in
+  case logLevel of
+    LogInfo                        -> logRequest
+    LogWarn  | status >= status400 -> logRequest
+    LogError | status >= status500 -> logRequest
+    _                              -> sendResponse res
 
 -- | CORS policy to be used in by Wai Cors middleware
 corsPolicy :: Wai.Request -> Maybe Wai.CorsResourcePolicy