refactor(storage): new storage file structure

- new directory structure containing manifest.json and one json file per provider, by default.
- the manifest.json file can specify a filepath for each vpn provider
- each vpn provider json data file can contain the `"preferred": true` field to enforce it is used even if outdated, unless there is a version mismatch
- `STORAGE_SERVERS_DIRECTORY_PATH` replaces `STORAGE_FILEPATH` (which is now a migration source only). It sets the directory where server manifest and per-provider JSON files are stored (default: `/gluetun/servers/`).
- First-run migration: On startup, gluetun checks for the old /gluetun/servers.json file; if found and no new manifest exists, it automatically migrates all data to /gluetun/servers/ directory structure
- Silent fallback: If legacy file isn't found, uses the new directory path normally
- Legacy cleanup: After successful migration, attempts to remove the old fat JSON file (logs warning only if removal fails, e.g., read-only bind mounts)

gluetun-servers/pkg/updaters/providers/windscribe/servers.go

@@ -0,0 +1,73 @@
+package windscribe
+
+import (
+	"context"
+	"fmt"
+	"net/netip"
+	"sort"
+
+	"github.com/qdm12/gluetun-servers/pkg/constants"
+	"github.com/qdm12/gluetun-servers/pkg/models"
+	"github.com/qdm12/gluetun-servers/pkg/updaters/common"
+)
+
+func (u *Updater) FetchServers(ctx context.Context, minServers int) (
+	servers []models.Server, err error,
+) {
+	data, err := fetchAPI(ctx, u.client)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, regionData := range data.Data {
+		region := regionData.Region
+		for _, group := range regionData.Groups {
+			city := group.City
+			x5090Name := group.OvpnX509
+			wgPubKey := group.WgPubKey
+			for _, node := range group.Nodes {
+				ips := make([]netip.Addr, 0, 2) //nolint:mnd
+				if node.IP.IsValid() {
+					ips = append(ips, node.IP)
+				}
+				if node.IP2.IsValid() {
+					ips = append(ips, node.IP2)
+				}
+				server := models.Server{
+					VPN:      constants.OpenVPN,
+					TCP:      true,
+					UDP:      true,
+					Region:   region,
+					City:     city,
+					Hostname: node.Hostname,
+					OvpnX509: x5090Name,
+					IPs:      ips,
+				}
+				servers = append(servers, server)
+
+				if !node.IP3.IsValid() { // Wireguard + Stealth
+					continue
+				} else if wgPubKey == "" {
+					return nil, fmt.Errorf("no wireguard public key found: for node %s", node.Hostname)
+				}
+
+				server.VPN = constants.Wireguard
+				server.UDP = false
+				server.TCP = false
+				server.OvpnX509 = ""
+				server.WgPubKey = wgPubKey
+				server.IPs = []netip.Addr{node.IP3}
+				servers = append(servers, server)
+			}
+		}
+	}
+
+	if len(servers) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(servers), minServers)
+	}
+
+	sort.Sort(models.SortableServers(servers))
+
+	return servers, nil
+}