Maintenance: refactor servers updater code

- Require at least 80% of number of servers now to pass
- Each provider is in its own package with a common structure
- Unzip package with unzipper interface
- Openvpn package with extraction and download functions

internal/updater/providers/torguard/filename.go

@@ -0,0 +1,31 @@
+package torguard
+
+import "strings"
+
+func parseFilename(fileName string) (country, city string) {
+	const prefix = "TorGuard."
+	const suffix = ".ovpn"
+	s := strings.TrimPrefix(fileName, prefix)
+	s = strings.TrimSuffix(s, suffix)
+
+	switch {
+	case strings.Count(s, ".") == 1 && !strings.HasPrefix(s, "USA"):
+		parts := strings.Split(s, ".")
+		country = parts[0]
+		city = parts[1]
+
+	case strings.HasPrefix(s, "USA"):
+		country = "USA"
+		s = strings.TrimPrefix(s, "USA-")
+		s = strings.ReplaceAll(s, "-", " ")
+		s = strings.ReplaceAll(s, ".", " ")
+		s = strings.ToLower(s)
+		s = strings.Title(s)
+		city = s
+
+	default:
+		country = s
+	}
+
+	return country, city
+}

internal/updater/providers/torguard/servers.go

@@ -0,0 +1,76 @@
+// Package torguard contains code to obtain the server information
+// for the Torguard provider.
+package torguard
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/updater/openvpn"
+	"github.com/qdm12/gluetun/internal/updater/unzip"
+)
+
+var ErrNotEnoughServers = errors.New("not enough servers found")
+
+func GetServers(ctx context.Context, unzipper unzip.Unzipper, minServers int) (
+	servers []models.TorguardServer, warnings []string, err error) {
+	const url = "https://torguard.net/downloads/OpenVPN-TCP-Linux.zip"
+	contents, err := unzipper.FetchAndExtract(ctx, url)
+	if err != nil {
+		return nil, nil, err
+	} else if len(contents) < minServers {
+		return nil, nil, fmt.Errorf("%w: %d and expected at least %d",
+			ErrNotEnoughServers, len(contents), minServers)
+	}
+
+	servers = make([]models.TorguardServer, 0, len(contents))
+	for fileName, content := range contents {
+		if !strings.HasSuffix(fileName, ".ovpn") {
+			continue // not an OpenVPN file
+		}
+
+		country, city := parseFilename(fileName)
+
+		host, warning, err := openvpn.ExtractHost(content)
+		if warning != "" {
+			warnings = append(warnings, warning)
+		}
+		if err != nil {
+			// treat error as warning and go to next file
+			warning := err.Error() + " in " + fileName
+			warnings = append(warnings, warning)
+			continue
+		}
+
+		ip, warning, err := openvpn.ExtractIP(content)
+		if warning != "" {
+			warnings = append(warnings, warning)
+		}
+		if err != nil {
+			// treat error as warning and go to next file
+			warning := err.Error() + " in " + fileName
+			warnings = append(warnings, warning)
+			continue
+		}
+
+		server := models.TorguardServer{
+			Country:  country,
+			City:     city,
+			Hostname: host,
+			IP:       ip,
+		}
+		servers = append(servers, server)
+	}
+
+	if len(servers) < minServers {
+		return nil, warnings, fmt.Errorf("%w: %d and expected at least %d",
+			ErrNotEnoughServers, len(servers), minServers)
+	}
+
+	sortServers(servers)
+
+	return servers, warnings, nil
+}

internal/updater/providers/torguard/sort.go

@@ -0,0 +1,19 @@
+package torguard
+
+import (
+	"sort"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
+
+func sortServers(servers []models.TorguardServer) {
+	sort.Slice(servers, func(i, j int) bool {
+		if servers[i].Country == servers[j].Country {
+			if servers[i].City == servers[j].City {
+				return servers[i].Hostname < servers[j].Hostname
+			}
+			return servers[i].City < servers[j].City
+		}
+		return servers[i].Country < servers[j].Country
+	})
+}

internal/updater/providers/torguard/string.go

@@ -0,0 +1,14 @@
+package torguard
+
+import "github.com/qdm12/gluetun/internal/models"
+
+func Stringify(servers []models.TorguardServer) (s string) {
+	s = "func TorguardServers() []models.TorguardServer {\n"
+	s += "	return []models.TorguardServer{\n"
+	for _, server := range servers {
+		s += "		" + server.String() + ",\n"
+	}
+	s += "	}\n"
+	s += "}"
+	return s
+}