chore(settings): refactor settings processing (#756)

- Better settings tree structure logged using `qdm12/gotree`
- Read settings from environment variables, then files, then secret files
- Settings methods to default them, merge them and override them
- `DNS_PLAINTEXT_ADDRESS` default changed to `127.0.0.1` to use DoT. Warning added if set to something else.
- `HTTPPROXY_LISTENING_ADDRESS` instead of `HTTPPROXY_PORT` (with retro-compatibility)

internal/provider/vpnunlimited/connection.go

@@ -3,7 +3,7 @@ package vpnunlimited
 import (
 	"errors"
 
-	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/utils"
@@ -11,11 +11,11 @@ import (
 
 var ErrProtocolUnsupported = errors.New("network protocol is not supported")
 
-func (p *Provider) GetConnection(selection configuration.ServerSelection) (
+func (p *Provider) GetConnection(selection settings.ServerSelection) (
 	connection models.Connection, err error) {
 	const port = 1194
 	const protocol = constants.UDP
-	if selection.OpenVPN.TCP {
+	if *selection.OpenVPN.TCP {
 		return connection, ErrProtocolUnsupported
 	}
 

internal/provider/vpnunlimited/filter.go

@@ -1,12 +1,12 @@
 package vpnunlimited
 
 import (
-	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/utils"
 )
 
-func (p *Provider) filterServers(selection configuration.ServerSelection) (
+func (p *Provider) filterServers(selection settings.ServerSelection) (
 	servers []models.VPNUnlimitedServer, err error) {
 	for _, server := range p.servers {
 		switch {
@@ -14,8 +14,8 @@ func (p *Provider) filterServers(selection configuration.ServerSelection) (
 			utils.FilterByPossibilities(server.Country, selection.Countries),
 			utils.FilterByPossibilities(server.City, selection.Cities),
 			utils.FilterByPossibilities(server.Hostname, selection.Hostnames),
-			selection.FreeOnly && !server.Free,
-			selection.StreamOnly && !server.Stream,
+			*selection.FreeOnly && !server.Free,
+			*selection.StreamOnly && !server.Stream,
 			utils.FilterByProtocol(selection, server.TCP, server.UDP):
 		default:
 			servers = append(servers, server)

internal/provider/vpnunlimited/openvpnconf.go

@@ -1,22 +1,24 @@
 package vpnunlimited
 
 import (
+	"fmt"
 	"strconv"
 
-	"github.com/qdm12/gluetun/internal/configuration"
+	"github.com/qdm12/gluetun/internal/configuration/settings"
 	"github.com/qdm12/gluetun/internal/constants"
 	"github.com/qdm12/gluetun/internal/models"
+	"github.com/qdm12/gluetun/internal/openvpn/parse"
 	"github.com/qdm12/gluetun/internal/provider/utils"
 )
 
 func (p *Provider) BuildConf(connection models.Connection,
-	settings configuration.OpenVPN) (lines []string, err error) {
+	settings settings.OpenVPN) (lines []string, err error) {
 	lines = []string{
 		"client",
 		"nobind",
 		"tls-exit",
 		"dev " + settings.Interface,
-		"verb " + strconv.Itoa(settings.Verbosity),
+		"verb " + strconv.Itoa(*settings.Verbosity),
 
 		// VPNUnlimited specific
 		"ping 5",
@@ -40,35 +42,43 @@ func (p *Provider) BuildConf(connection models.Connection,
 		lines = append(lines, utils.CipherLines(settings.Ciphers, settings.Version)...)
 	}
 
-	if settings.Auth != "" {
-		lines = append(lines, "auth "+settings.Auth)
+	if *settings.Auth != "" {
+		lines = append(lines, "auth "+*settings.Auth)
 	}
 
-	if settings.MSSFix > 0 {
-		lines = append(lines, "mssfix "+strconv.Itoa(int(settings.MSSFix)))
+	if *settings.MSSFix > 0 {
+		lines = append(lines, "mssfix "+strconv.Itoa(int(*settings.MSSFix)))
 	}
 
 	if connection.Protocol == constants.UDP {
 		lines = append(lines, "explicit-exit-notify")
 	}
 
-	if !settings.Root {
+	if !*settings.Root {
 		lines = append(lines, "user "+settings.ProcUser)
 		lines = append(lines, "persist-tun")
 		lines = append(lines, "persist-key")
 	}
 
-	if !settings.IPv6 {
+	if !*settings.IPv6 {
 		lines = append(lines, `pull-filter ignore "route-ipv6"`)
 		lines = append(lines, `pull-filter ignore "ifconfig-ipv6"`)
 	}
 
 	lines = append(lines, utils.WrapOpenvpnCA(
 		constants.VPNUnlimitedCertificateAuthority)...)
-	lines = append(lines, utils.WrapOpenvpnCert(
-		settings.ClientCrt)...)
-	lines = append(lines, utils.WrapOpenvpnKey(
-		settings.ClientKey)...)
+
+	certData, err := parse.ExtractCert([]byte(*settings.ClientCrt))
+	if err != nil {
+		return nil, fmt.Errorf("client cert is not valid: %w", err)
+	}
+	lines = append(lines, utils.WrapOpenvpnCert(certData)...)
+
+	keyData, err := parse.ExtractPrivateKey([]byte(*settings.ClientKey))
+	if err != nil {
+		return nil, fmt.Errorf("client key is not valid: %w", err)
+	}
+	lines = append(lines, utils.WrapOpenvpnKey(keyData)...)
 
 	lines = append(lines, "")