Support logging to PSQL; general improvement to logging effect; cleanup and clarification of names

src/Handlers.hs

@@ -2,6 +2,7 @@ module Handlers where
 
 import Core
 import Database
+import Logger
 
 import qualified Data.ByteString.Char8    as C
 import Data.List
@@ -13,20 +14,26 @@ import Effectful.FileSystem.IO.ByteString as EBS
 import Servant hiding                     ((:>), throwError)
 import qualified Servant                  as S
 
-rootHandler :: (Error ServerError :> es) => Eff es T.Text
-rootHandler = return "Hello, World!"
+type CRUD es = ( Database :> es, Logger :> es, Error ServerError :> es )
 
-userListHandler :: ( Database :> es, Error ServerError :> es) => Eff es [User]
-userListHandler = databaseRead_ "SELECT id, name FROM users"
+rootHandler :: (Logger :> es, Error ServerError :> es) => Eff es T.Text
+rootHandler = (writeLog Info "Hit the root!") >>= \_ ->
+  return "Hello, World!"
 
-userGetHandler :: (Database :> es, Error ServerError :> es)
-               => Int -> Eff es User
+userListHandler :: CRUD es => Eff es [User]
+userListHandler = (writeLog Info "Selected all users!") >>= \_ -> 
+  databaseRead_ "SELECT id, name FROM users"
+
+userGetHandler :: CRUD es => UserId -> Eff es User
 userGetHandler userId = databaseRead (queryUser userId) >>= \mUser ->
   case mUser of
     (a:_) -> pure a
-    []    -> pure (User 0 "No user found")
+    []    -> pure (User (UserId 0) "No user found")
 
-userPostHandler :: ( Database :> es, Error ServerError :> es)
-                => String -> Eff es NoContent
+userPostHandler :: CRUD es => T.Text -> Eff es NoContent
 userPostHandler name =
   databaseWrite (writeUser name) >>= \_ -> return NoContent
+
+userDeleteHandler :: CRUD es => UserId -> Eff es NoContent
+userDeleteHandler userId =
+  databaseWrite (deleteUser userId) >>= \_ -> return NoContent