chore(settings): simplify/flatten userdb config settings

config/settings.yml

@@ -131,13 +131,12 @@ auto-db-migrate: '_env:AUTO_DB_MIGRATE:true'
 # External databases used for authentication and user data lookup
 # If the first user database in the list is unreachable, the application will perform a failover to the next list entry, etc.
 user-database:
-  mode: simple
+  mode: single-source
+  protocol: oauth2
   config:
-    protocol: "oauth2"
-    config:
-      client-id:      "_env:OAUTH2CLIENTID:"
-      client-secret:  "_env:OAUTH2CLIENTSECRET:"
-      tenant-id:      "_env:OAUTH2TENANTID:"
+    client-id:      "_env:OAUTH2CLIENTID:"
+    client-secret:  "_env:OAUTH2CLIENTSECRET:"
+    tenant-id:      "_env:OAUTH2TENANTID:"
     # protocol: "ldap"
     # config:
     #   host:           "_env:LDAPHOST:"

src/Settings.hs

@@ -146,16 +146,16 @@ data UserDbConf' = UserDbLdap LdapConf | UserDbOAuth2 OAuth2Conf
   deriving (Show)
 
 data UserDbConf =
-      UserDbSimple -- ^ use only one specific source
-      { userdbSource :: UserDbConf'
+      UserDbSingleSource -- ^ use only one specific source
+      { userdbSingleSource :: UserDbConf'
       }
   -- TODO: other modes yet to be implemented
   -- | UserDbFailover  -- ^ use only one user source at a time, but failover to the next-best database if the current source is unavailable
   --   { userdbFailoverSources :: PointedList UserDbConf
   --   , userDbFailoverRetest  :: NominalDiffTime
   --   }
-  -- | UserDbMerge  -- ^ Multiple coequal user sources
-  --   { userdbMergeSources :: Set UserDbConf
+  -- | UserDbMultiSource  -- ^ Multiple coequal user sources
+  --   { userdbMultiSources :: Set UserDbConf
   --   }
   deriving (Show)
 
@@ -318,14 +318,12 @@ deriveFromJSON defaultOptions
   , sumEncoding = TaggedObject "protocol" "config"
   } ''UserDbConf'
 
-instance FromJSON UserDbConf where
-  parseJSON = withObject "UserDbConf" $ \o -> do
-    mode <- o .: "mode"
-    case mode of
-      "simple" -> do
-        userdbSource <- o .: "config"
-        return UserDbSimple{..}
-      other -> error $ "Unsupported user database mode: " <> other
+deriveFromJSON defaultOptions
+  { constructorTagModifier = camelToPathPiece' 1
+  , fieldLabelModifier = camelToPathPiece' 1
+  , sumEncoding = TaggedObject "mode" "config"
+  , unwrapUnaryRecords = True
+  } ''UserDbConf
 
 instance FromJSON HaskellNet.PortNumber where
   parseJSON = withScientific "PortNumber" $ \sciNum -> case Scientific.toBoundedInteger sciNum of