fix: don't enable admin server /config by default

This now requires setting `admin-server-config-enabled`.

src/PostgREST/Admin.hs

@@ -56,8 +56,11 @@ admin appState req respond  = do
       in
       respond $ Wai.responseLBS status [] mempty
     ["config"] -> do
-      config <- AppState.getConfig appState
-      respond $ Wai.responseLBS HTTP.status200 [] (LBS.fromStrict $ encodeUtf8 $ Config.toText config)
+      config@Config.AppConfig{configAdminServerConfigEnabled} <- AppState.getConfig appState
+      if configAdminServerConfigEnabled then
+        respond $ Wai.responseLBS HTTP.status200 [] (LBS.fromStrict $ encodeUtf8 $ Config.toText config)
+      else
+        respond $ Wai.responseLBS HTTP.status404 [] mempty
     ["schema_cache"] -> do
       sCache <- AppState.getSchemaCache appState
       respond $ Wai.responseLBS HTTP.status200 [] (maybe mempty JSON.encode sCache)

src/PostgREST/CLI.hs

@@ -128,6 +128,9 @@ exampleConfigFile =
   [str|## Admin server used for checks. It's disabled by default unless a port is specified.
       |# admin-server-port = 3001
       |
+      |## Whether to enable the /config endpoint of the admin server
+      |# admin-server-config-enabled = false
+      |
       |## The database role to use when no client authentication is provided
       |# db-anon-role = "anon"
       |

src/PostgREST/Config.hs

@@ -110,6 +110,7 @@ data AppConfig = AppConfig
   , configServerUnixSocket         :: Maybe FilePath
   , configServerUnixSocketMode     :: FileMode
   , configAdminServerPort          :: Maybe Int
+  , configAdminServerConfigEnabled :: Bool
   , configRoleSettings             :: RoleSettings
   , configRoleIsoLvl               :: RoleIsolationLvl
   , configInternalSCSleep          :: Maybe Int32
@@ -180,6 +181,7 @@ toText conf =
       ,("server-unix-socket",        q . maybe mempty T.pack . configServerUnixSocket)
       ,("server-unix-socket-mode",   q . T.pack . showSocketMode)
       ,("admin-server-port",             maybe "\"\"" show . configAdminServerPort)
+      ,("admin-server-config-enabled",             T.toLower . show . configAdminServerConfigEnabled)
       ]
 
     -- quote all app.settings
@@ -286,6 +288,7 @@ parser optPath env dbSettings roleSettings roleIsolationLvl =
     <*> (fmap T.unpack <$> optString "server-unix-socket")
     <*> parseSocketFileMode "server-unix-socket-mode"
     <*> optInt "admin-server-port"
+    <*> (fromMaybe False <$> optBool "admin-server-config-enabled")
     <*> pure roleSettings
     <*> pure roleIsolationLvl
     <*> optInt "internal-schema-cache-sleep"