add config

lib/Config.hs

@@ -0,0 +1,45 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Config
+  ( parserOpts
+  , AppConfig(..)
+  ) where
+
+import Options.Applicative
+import Data.Text (Text)
+
+data AppConfig = AppConfig
+  { appPort :: Int
+  , appDbFile :: FilePath
+  , appUser :: Text
+  , appPassHash :: Text
+  } deriving (Show, Eq)
+
+appConfig :: Parser AppConfig
+appConfig = AppConfig
+  <$> option auto
+     ( long "port"
+     <> help "port to listen"
+     <> showDefault
+     <> value 8000
+     <> metavar "INT")
+   <*> strOption
+     ( long "dbpath"
+     <> help "sqlite db file path"
+     <> showDefault
+     <> value "quotes.db"
+     <> metavar "TARGET")
+    <*> strOption
+     ( long "user"
+     <> help "basic auth user (for writes)"
+     <> showDefault
+     <> value "root"
+     <> metavar "USER")
+    <*> strOption
+     ( long "password"
+     <> help "password hash for basic auth user, generate with argon2")
+
+parserOpts :: ParserInfo AppConfig
+parserOpts =  info (appConfig <**> helper)
+      ( fullDesc
+     <> progDesc "Serve Quotes API"
+     <> header "quotes api" )