Implement envy

app/Main.hs

@@ -10,6 +10,7 @@ import Control.Monad.IO.Class (liftIO)
 import Control.Monad.Trans.Except (ExceptT (..), runExceptT)
 import Data.Proxy (Proxy (..))
 import Data.Time (Day, toGregorian)
+import GHC.Generics (Generic)
 import Network.HTTP.Media ((//), (/:))
 import Network.HTTP.Types (Status (..), mkStatus, status200)
 import Servant
@@ -31,7 +32,6 @@ import Servant
   , (:>)
   , pattern MkHandler
   )
-import System.Exit (exitWith, ExitCode (..))
 import System.FilePath ((</>))
 import Text.Blaze.Html.Renderer.Utf8 (renderHtml)
 import Text.Blaze.Html5 ((!))
@@ -51,25 +51,32 @@ import Yore.DB (DayFile (..))
 import Yore.Error (Error (..))
 import Yore.Time (addYears, getCurrentDay, getSecondsUntilMidnight)
 
-import qualified Yore.Config as Config
+import qualified Envy
 import qualified Yore.DB as DB
 import qualified Yore.Log as Log
 
+data Config f = Config
+  { port :: Envy.Env f (Envy.Optional Integer 3000)
+  , downloadDir :: Envy.Env f (Envy.Optional String "download")
+  , factor :: Envy.Env f (Envy.Required Rational)
+  , factorFallback :: Envy.Env f (Envy.Optional Rational '(1, 1))
+  }
+  deriving (Generic)
+
 main :: IO ()
 main = do
-  cfg <- Config.load @Config.Config >>= \case
-    Left err -> do
-      Log.error err
-      exitWith $ ExitFailure 1
-    Right cfg ->
-      pure cfg
+  print . port =<< Envy.load @Config
+  print . downloadDir =<< Envy.load @Config
+  print . factor =<< Envy.load @Config
+  let
+    settings =
+      Warp.setLogger logger $
+        Warp.setPort 3000 $
+          Warp.setOnException onException Warp.defaultSettings
+
   db <- DB.initDB "host=localhost user=yore-test port=5433 dbname=yore-test"
   Warp.runSettings settings $ serve (Proxy :: Proxy API) $ hoistServer (Proxy :: Proxy API) nt $ server db
   where
-    settings =
-      Warp.setLogger logger $
-        Warp.setOnException onException Warp.defaultSettings
-
     logger req status _ = do
       Log.info $
         printf