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- each vpn provider json data file can contain the `"preferred": true` field to enforce it is used even if outdated, unless there is a version mismatch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/ip2location.go

@@ -0,0 +1,138 @@
+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 ip2Location struct {
+	client       *http.Client
+	token        string
+	countryCodes map[string]string
+}
+
+func newIP2Location(client *http.Client, token string) *ip2Location {
+	return &ip2Location{
+		client:       client,
+		token:        token,
+		countryCodes: constants.CountryCodes(),
+	}
+}
+
+func (i *ip2Location) String() string {
+	return string(IP2Location)
+}
+
+func (i *ip2Location) CanFetchAnyIP() bool {
+	return true
+}
+
+func (i *ip2Location) Token() string {
+	return i.token
+}
+
+// FetchInfo obtains information on the ip address provided
+// using the api.ip2location.io API. If the ip is the zero value,
+// the public IP address of the machine is used as the IP.
+func (i *ip2Location) 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://api.ip2location.io/"
+	if ip.IsValid() {
+		url += "?ip=" + ip.String()
+	}
+
+	if i.token != "" {
+		if !strings.Contains(url, "?") {
+			url += "?"
+		}
+		url += "&key=" + i.token
+	}
+
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return result, err
+	}
+
+	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"`
+		CountryName string     `json:"country_name,omitempty"`
+		RegionName  string     `json:"region_name,omitempty"`
+		CityName    string     `json:"city_name,omitempty"`
+		Latitude    float32    `json:"latitude,omitempty"`
+		Longitude   float32    `json:"longitude,omitempty"`
+		ZipCode     string     `json:"zip_code,omitempty"`
+		// Timezone in the form -07:00
+		Timezone string `json:"time_zone,omitempty"`
+		As       string `json:"as,omitempty"`
+	}
+	if err := decoder.Decode(&data); err != nil {
+		return result, fmt.Errorf("decoding response: %w", err)
+	}
+
+	// Remove parentheses from country name
+	idx := strings.Index(data.CountryName, " (")
+	if idx != -1 {
+		data.CountryName = data.CountryName[:idx]
+	}
+
+	// Rename country to match country string obtained from other IP data sources
+	countryRenames := map[string]string{
+		"Netherlands":              i.countryCodes["nl"],
+		"United States of America": i.countryCodes["us"],
+		"United Kingdom of Great Britain and Northern Ireland": i.countryCodes["gb"],
+		"Czechia": i.countryCodes["cz"],
+		"Korea":   i.countryCodes["kr"],
+	}
+	if newName, ok := countryRenames[data.CountryName]; ok {
+		data.CountryName = newName
+	}
+
+	result = models.PublicIP{
+		IP:           data.IP,
+		Region:       data.RegionName,
+		Country:      data.CountryName,
+		City:         data.CityName,
+		Hostname:     "", // no hostname
+		Location:     fmt.Sprintf("%f,%f", data.Latitude, data.Longitude),
+		Organization: data.As,
+		PostalCode:   data.ZipCode,
+		Timezone:     data.Timezone,
+	}
+	return result, nil
+}