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- each vpn provider json data file can contain the `"preferred": true` field to enforce it is used even if outdated, unless there is a version mismatch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/privado/servers.go

@@ -0,0 +1,70 @@
+package privado
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"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,
+) {
+	const url = "https://privadovpn.com/apps/servers_export.json"
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+
+	response, err := u.client.Do(request)
+	if err != nil {
+		return nil, err
+	}
+
+	var data struct {
+		Servers []struct {
+			Country  string     `json:"country"`
+			City     string     `json:"city"`
+			Hostname string     `json:"hostname"`
+			IP       netip.Addr `json:"ip"`
+		} `json:"servers"`
+	}
+	decoder := json.NewDecoder(response.Body)
+	err = decoder.Decode(&data)
+	if err != nil {
+		_ = response.Body.Close()
+		return nil, fmt.Errorf("decoding JSON response: %w", err)
+	}
+
+	err = response.Body.Close()
+	if err != nil {
+		return nil, fmt.Errorf("closing response body: %w", err)
+	}
+
+	if len(data.Servers) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(data.Servers), minServers)
+	}
+
+	servers = make([]models.Server, len(data.Servers))
+	for i, server := range data.Servers {
+		servers[i] = models.Server{
+			VPN:      constants.OpenVPN,
+			Country:  server.Country,
+			City:     server.City,
+			Hostname: server.Hostname,
+			IPs:      []netip.Addr{server.IP},
+			UDP:      true,
+		}
+	}
+
+	sort.Sort(models.SortableServers(servers))
+
+	return servers, nil
+}

gluetun-servers/pkg/updaters/providers/privado/updater.go

@@ -0,0 +1,27 @@
+package privado
+
+import (
+	"net/http"
+
+	"github.com/qdm12/gluetun-servers/pkg/updaters/common"
+)
+
+type Updater struct {
+	client *http.Client
+	warner common.Warner
+}
+
+func New(client *http.Client, warner common.Warner) *Updater {
+	return &Updater{
+		client: client,
+		warner: warner,
+	}
+}
+
+func (u *Updater) Version() uint16 {
+	return 6 //nolint:mnd
+}
+
+func (u *Updater) Name() string {
+	return "privado"
+}