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/fastestvpn/filename.go

@@ -0,0 +1,39 @@
+package fastestvpn
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+var errFilenameNoProtocolSuffix = errors.New("filename does not have a protocol suffix")
+
+var trailNumberExp = regexp.MustCompile(`[0-9]+$`)
+
+func parseFilename(fileName string) (
+	country string, tcp, udp bool, err error,
+) {
+	const (
+		tcpSuffix = "-TCP.ovpn"
+		udpSuffix = "-UDP.ovpn"
+	)
+	var suffix string
+	switch {
+	case strings.HasSuffix(fileName, tcpSuffix):
+		suffix = tcpSuffix
+		tcp = true
+	case strings.HasSuffix(fileName, udpSuffix):
+		suffix = udpSuffix
+		udp = true
+	default:
+		return "", false, false, fmt.Errorf("%w: %s",
+			errFilenameNoProtocolSuffix, fileName)
+	}
+
+	countryWithNumber := strings.TrimSuffix(fileName, suffix)
+	number := trailNumberExp.FindString(countryWithNumber)
+	country = countryWithNumber[:len(countryWithNumber)-len(number)]
+
+	return country, tcp, udp, nil
+}

internal/updater/providers/fastestvpn/hosttoserver.go

@@ -0,0 +1,53 @@
+package fastestvpn
+
+import (
+	"net"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
+
+type hostToServer map[string]models.FastestvpnServer
+
+func (hts hostToServer) add(host, country string, tcp, udp bool) {
+	server, ok := hts[host]
+	if !ok {
+		server.Hostname = host
+		server.Country = country
+	}
+	if tcp {
+		server.TCP = true
+	}
+	if udp {
+		server.UDP = true
+	}
+	hts[host] = server
+}
+
+func (hts hostToServer) toHostsSlice() (hosts []string) {
+	hosts = make([]string, 0, len(hts))
+	for host := range hts {
+		hosts = append(hosts, host)
+	}
+	return hosts
+}
+
+func (hts hostToServer) adaptWithIPs(hostToIPs map[string][]net.IP) {
+	for host, IPs := range hostToIPs {
+		server := hts[host]
+		server.IPs = IPs
+		hts[host] = server
+	}
+	for host, server := range hts {
+		if len(server.IPs) == 0 {
+			delete(hts, host)
+		}
+	}
+}
+
+func (hts hostToServer) toServersSlice() (servers []models.FastestvpnServer) {
+	servers = make([]models.FastestvpnServer, 0, len(hts))
+	for _, server := range hts {
+		servers = append(servers, server)
+	}
+	return servers
+}

internal/updater/providers/fastestvpn/resolve.go

@@ -0,0 +1,30 @@
+package fastestvpn
+
+import (
+	"context"
+	"net"
+	"time"
+
+	"github.com/qdm12/gluetun/internal/updater/resolver"
+)
+
+func resolveHosts(ctx context.Context, presolver resolver.Parallel,
+	hosts []string, minServers int) (hostToIPs map[string][]net.IP,
+	warnings []string, err error) {
+	const (
+		maxFailRatio = 0.1
+		maxNoNew     = 1
+		maxFails     = 2
+	)
+	settings := resolver.ParallelSettings{
+		MaxFailRatio: maxFailRatio,
+		MinFound:     minServers,
+		Repeat: resolver.RepeatSettings{
+			MaxDuration: time.Second,
+			MaxNoNew:    maxNoNew,
+			MaxFails:    maxFails,
+			SortIPs:     true,
+		},
+	}
+	return presolver.Resolve(ctx, hosts, settings)
+}

internal/updater/providers/fastestvpn/servers.go

@@ -0,0 +1,82 @@
+// Package fastestvpn contains code to obtain the server information
+// for the FastestVPN provider.
+package fastestvpn
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/updater/openvpn"
+	"github.com/qdm12/gluetun/internal/updater/resolver"
+	"github.com/qdm12/gluetun/internal/updater/unzip"
+)
+
+var ErrNotEnoughServers = errors.New("not enough servers found")
+
+func GetServers(ctx context.Context, unzipper unzip.Unzipper,
+	presolver resolver.Parallel, minServers int) (
+	servers []models.FastestvpnServer, warnings []string, err error) {
+	const url = "https://support.fastestvpn.com/download/openvpn-tcp-udp-config-files"
+	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)
+	}
+
+	hts := make(hostToServer)
+
+	for fileName, content := range contents {
+		if !strings.HasSuffix(fileName, ".ovpn") {
+			continue // not an OpenVPN file
+		}
+
+		country, tcp, udp, err := parseFilename(fileName)
+		if err != nil {
+			warnings = append(warnings, err.Error())
+			continue
+		}
+
+		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
+		}
+
+		hts.add(host, country, tcp, udp)
+	}
+
+	if len(hts) < minServers {
+		return nil, warnings, fmt.Errorf("%w: %d and expected at least %d",
+			ErrNotEnoughServers, len(hts), minServers)
+	}
+
+	hosts := hts.toHostsSlice()
+	hostToIPs, newWarnings, err := resolveHosts(ctx, presolver, hosts, minServers)
+	warnings = append(warnings, newWarnings...)
+	if err != nil {
+		return nil, warnings, err
+	}
+
+	hts.adaptWithIPs(hostToIPs)
+
+	servers = hts.toServersSlice()
+
+	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/fastestvpn/sort.go

@@ -0,0 +1,16 @@
+package fastestvpn
+
+import (
+	"sort"
+
+	"github.com/qdm12/gluetun/internal/models"
+)
+
+func sortServers(servers []models.FastestvpnServer) {
+	sort.Slice(servers, func(i, j int) bool {
+		if servers[i].Country == servers[j].Country {
+			return servers[i].Hostname < servers[j].Hostname
+		}
+		return servers[i].Country < servers[j].Country
+	})
+}

internal/updater/providers/fastestvpn/string.go

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