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- each vpn provider json data file can contain the `"preferred": true` field to enforce it is used even if outdated, unless there is a version mismatch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

@@ -0,0 +1,120 @@
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"net/netip"
+	"strings"
+	"time"
+
+	"github.com/qdm12/gluetun-servers/pkg/constants"
+	"github.com/qdm12/gluetun-servers/pkg/publicip/models"
+)
+
+type ipInfo struct {
+	client *http.Client
+	token  string
+}
+
+func newIPInfo(client *http.Client, token string) *ipInfo {
+	return &ipInfo{
+		client: client,
+		token:  token,
+	}
+}
+
+func (i *ipInfo) String() string {
+	return string(IPInfo)
+}
+
+func (i *ipInfo) CanFetchAnyIP() bool {
+	return true
+}
+
+func (i *ipInfo) Token() string {
+	return i.token
+}
+
+// FetchInfo obtains information on the ip address provided
+// using the ipinfo.io API. If the ip is the zero value, the public IP address
+// of the machine is used as the IP.
+func (i *ipInfo) FetchInfo(ctx context.Context, ip netip.Addr) (
+	result models.PublicIP, err error,
+) {
+	// Define a timeout since the default client has a large timeout and we don't
+	// want to wait too long.
+	const timeout = 15 * time.Second
+	ctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	url := "https://ipinfo.io/"
+	switch {
+	case ip.Is6():
+		url = "https://v6.ipinfo.io/" + ip.String()
+	case ip.Is4():
+		url = "https://ipinfo.io/" + ip.String()
+	}
+
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return result, err
+	}
+	request.Header.Set("Authorization", "Bearer "+i.token)
+
+	response, err := i.client.Do(request)
+	if err != nil {
+		return result, err
+	}
+	defer response.Body.Close()
+
+	if i.token != "" && response.StatusCode == http.StatusUnauthorized {
+		return result, fmt.Errorf("token is not valid: %s", response.Status)
+	}
+
+	switch response.StatusCode {
+	case http.StatusOK:
+	case http.StatusTooManyRequests, http.StatusForbidden:
+		return result, fmt.Errorf("%w from %s: %d %s",
+			ErrTooManyRequests, url, response.StatusCode, response.Status)
+	default:
+		return result, fmt.Errorf("bad HTTP status received from %s: %d %s",
+			url, response.StatusCode, response.Status)
+	}
+
+	decoder := json.NewDecoder(response.Body)
+	var data struct {
+		IP       netip.Addr `json:"ip,omitempty"`
+		Region   string     `json:"region,omitempty"`
+		Country  string     `json:"country,omitempty"`
+		City     string     `json:"city,omitempty"`
+		Hostname string     `json:"hostname,omitempty"`
+		Loc      string     `json:"loc,omitempty"`
+		Org      string     `json:"org,omitempty"`
+		Postal   string     `json:"postal,omitempty"`
+		Timezone string     `json:"timezone,omitempty"`
+	}
+	if err := decoder.Decode(&data); err != nil {
+		return result, fmt.Errorf("decoding response: %w", err)
+	}
+
+	countryCode := strings.ToLower(data.Country)
+	country, ok := constants.CountryCodes()[countryCode]
+	if ok {
+		data.Country = country
+	}
+
+	result = models.PublicIP{
+		IP:           data.IP,
+		Region:       data.Region,
+		Country:      data.Country,
+		City:         data.City,
+		Hostname:     data.Hostname,
+		Location:     data.Loc,
+		Organization: data.Org,
+		PostalCode:   data.Postal,
+		Timezone:     data.Timezone,
+	}
+	return result, nil
+}