Maint: internal/storage rework

- No more global variables
- Inject merged servers to configuration package
- Fix #566: configuration parsing to use persisted servers.json
- Move server data files from `internal/constants` to `internal/storage`

cmd/gluetun/main.go

@@ -135,8 +135,16 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		}
 	}
 
+	// TODO run this in a loop or in openvpn to reload from file without restarting
+	storageLogger := logger.NewChild(logging.Settings{Prefix: "storage: "})
+	storage, err := storage.New(storageLogger, constants.ServersData)
+	if err != nil {
+		return err
+	}
+	allServers := storage.GetServers()
+
 	var allSettings configuration.Settings
-	err := allSettings.Read(env,
+	err = allSettings.Read(env, allServers,
 		logger.NewChild(logging.Settings{Prefix: "configuration: "}))
 	if err != nil {
 		return err
@@ -200,15 +208,6 @@ func _main(ctx context.Context, buildInfo models.BuildInformation,
 		return err
 	}
 
-	// TODO run this in a loop or in openvpn to reload from file without restarting
-	storage := storage.New(
-		logger.NewChild(logging.Settings{Prefix: "storage: "}),
-		constants.ServersData)
-	allServers, err := storage.SyncServers(constants.GetAllServers())
-	if err != nil {
-		return err
-	}
-
 	const defaultUsername = "nonrootuser"
 	nonRootUsername, err := alpineConf.CreateUser(defaultUsername, puid)
 	if err != nil {