add: config client-error-verbosity to set error verbosity

Set error verbosity using this config. The verbosity can
be set to `verbose` or `minimal` for client error responses.

This only affects client side HTTP responses, server side logs
are not affected by this config.

Signed-off-by: Taimoor Zaeem <taimoorzaeem@gmail.com>

src/PostgREST/App.hs

@@ -119,30 +119,31 @@ postgrest logLevel appState connWorker =
   Logger.middleware logLevel Auth.getRole $
     -- fromJust can be used, because the auth middleware will **always** add
     -- some AuthResult to the vault.
-    \req respond -> case fromJust $ Auth.getResult req of
-      Left err -> respond $ Error.errorResponseFor err
-      Right authResult -> do
-        appConf <- AppState.getConfig appState -- the config must be read again because it can reload
-        maybeSchemaCache <- AppState.getSchemaCache appState
+    \req respond -> do
+      appConf@AppConfig{..} <- AppState.getConfig appState -- the config must be read again because it can reload
+      case fromJust $ Auth.getResult req of
+        Left err -> respond $ Error.errorResponseFor configClientErrorVerbosity err
+        Right authResult -> do
+          maybeSchemaCache <- AppState.getSchemaCache appState
 
-        let
-          eitherResponse :: IO (Either Error Wai.Response)
-          eitherResponse =
-            runExceptT $ postgrestResponse appState appConf maybeSchemaCache authResult req
+          let
+            eitherResponse :: IO (Either Error Wai.Response)
+            eitherResponse =
+              runExceptT $ postgrestResponse appState appConf maybeSchemaCache authResult req
 
-        response <- either Error.errorResponseFor identity <$> eitherResponse
-        -- Launch the connWorker when the connection is down. The postgrest
-        -- function can respond successfully (with a stale schema cache) before
-        -- the connWorker is done. However, when there's an empty schema cache
-        -- postgrest responds with the error `PGRST002`; this means that the schema
-        -- cache is still loading, so we don't launch the connWorker here because
-        -- it would duplicate the loading process, e.g. https://github.com/PostgREST/postgrest/issues/3704
-        -- TODO: this process may be unnecessary when the Listener is enabled. Revisit once https://github.com/PostgREST/postgrest/issues/1766 is done
-        when (isServiceUnavailable response && isJust maybeSchemaCache) connWorker
-        resp <- do
-          delay <- AppState.getNextDelay appState
-          return $ addRetryHint delay response
-        respond resp
+          response <- either (Error.errorResponseFor configClientErrorVerbosity) identity <$> eitherResponse
+          -- Launch the connWorker when the connection is down. The postgrest
+          -- function can respond successfully (with a stale schema cache) before
+          -- the connWorker is done. However, when there's an empty schema cache
+          -- postgrest responds with the error `PGRST002`; this means that the schema
+          -- cache is still loading, so we don't launch the connWorker here because
+          -- it would duplicate the loading process, e.g. https://github.com/PostgREST/postgrest/issues/3704
+          -- TODO: this process may be unnecessary when the Listener is enabled. Revisit once https://github.com/PostgREST/postgrest/issues/1766 is done
+          when (isServiceUnavailable response && isJust maybeSchemaCache) connWorker
+          resp <- do
+            delay <- AppState.getNextDelay appState
+            return $ addRetryHint delay response
+          respond resp
 
 postgrestResponse
   :: AppState.AppState