updater: refactoring and set DNS server correctly

- Fix CLI operation not setting DNS server
- Fix periodic operation not setting DNS server
- Set DNS address for resolution once at start for both CLI and periodic operation
- Inject resolver to each provider instead of creating it within
- Use resolver settings on every call to `.Resolve` method, instead of passing it to constructor
- Move out minServers check from resolver

internal/provider/ivpn/updater/resolve.go

@@ -6,7 +6,7 @@ import (
 	"github.com/qdm12/gluetun/internal/updater/resolver"
 )
 
-func newParallelResolver() (parallelResolver *resolver.Parallel) {
+func parallelResolverSettings(hosts []string) (settings resolver.ParallelSettings) {
 	const (
 		maxFailRatio    = 0.1
 		maxDuration     = 20 * time.Second
@@ -14,7 +14,8 @@ func newParallelResolver() (parallelResolver *resolver.Parallel) {
 		maxNoNew        = 2
 		maxFails        = 2
 	)
-	settings := resolver.ParallelSettings{
+	return resolver.ParallelSettings{
+		Hosts:        hosts,
 		MaxFailRatio: maxFailRatio,
 		Repeat: resolver.RepeatSettings{
 			MaxDuration:     maxDuration,
@@ -24,5 +25,4 @@ func newParallelResolver() (parallelResolver *resolver.Parallel) {
 			SortIPs:         true,
 		},
 	}
-	return resolver.NewParallelResolver(settings)
 }

internal/provider/ivpn/updater/servers.go

@@ -38,7 +38,8 @@ func (u *Updater) FetchServers(ctx context.Context, minServers int) (
 			common.ErrNotEnoughServers, len(hosts), minServers)
 	}
 
-	hostToIPs, warnings, err := u.presolver.Resolve(ctx, hosts, minServers)
+	resolveSettings := parallelResolverSettings(hosts)
+	hostToIPs, warnings, err := u.presolver.Resolve(ctx, resolveSettings)
 	for _, warning := range warnings {
 		u.warner.Warn(warning)
 	}
@@ -46,6 +47,11 @@ func (u *Updater) FetchServers(ctx context.Context, minServers int) (
 		return nil, err
 	}
 
+	if len(hostToIPs) < minServers {
+		return nil, fmt.Errorf("%w: %d and expected at least %d",
+			common.ErrNotEnoughServers, len(servers), minServers)
+	}
+
 	servers = make([]models.Server, 0, len(hosts))
 	for _, serverData := range data.Servers {
 		vpnType := vpn.OpenVPN

internal/provider/ivpn/updater/servers_test.go

@@ -8,11 +8,13 @@ import (
 	"net/http"
 	"strings"
 	"testing"
+	"time"
 
 	"github.com/golang/mock/gomock"
 	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/qdm12/gluetun/internal/provider/common"
+	"github.com/qdm12/gluetun/internal/updater/resolver"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -33,7 +35,7 @@ func Test_Updater_GetServers(t *testing.T) {
 
 		// Resolution
 		expectResolve   bool
-		hostsToResolve  []string
+		resolveSettings resolver.ParallelSettings
 		hostToIPs       map[string][]net.IP
 		resolveWarnings []string
 		resolveErr      error
@@ -56,9 +58,19 @@ func Test_Updater_GetServers(t *testing.T) {
 			responseBody: `{"servers":[
 				{"hostnames":{"openvpn":"hosta"}}
 			]}`,
-			responseStatus:  http.StatusOK,
-			expectResolve:   true,
-			hostsToResolve:  []string{"hosta"},
+			responseStatus: http.StatusOK,
+			expectResolve:  true,
+			resolveSettings: resolver.ParallelSettings{
+				Hosts:        []string{"hosta"},
+				MaxFailRatio: 0.1,
+				Repeat: resolver.RepeatSettings{
+					MaxDuration:     20 * time.Second,
+					BetweenDuration: time.Second,
+					MaxNoNew:        2,
+					MaxFails:        2,
+					SortIPs:         true,
+				},
+			},
 			resolveWarnings: []string{"resolve warning"},
 			resolveErr:      errors.New("dummy"),
 			err:             errors.New("dummy"),
@@ -86,7 +98,17 @@ func Test_Updater_GetServers(t *testing.T) {
 			]}`,
 			responseStatus: http.StatusOK,
 			expectResolve:  true,
-			hostsToResolve: []string{"hosta", "hostb", "hostc"},
+			resolveSettings: resolver.ParallelSettings{
+				Hosts:        []string{"hosta", "hostb", "hostc"},
+				MaxFailRatio: 0.1,
+				Repeat: resolver.RepeatSettings{
+					MaxDuration:     20 * time.Second,
+					BetweenDuration: time.Second,
+					MaxNoNew:        2,
+					MaxFails:        2,
+					SortIPs:         true,
+				},
+			},
 			hostToIPs: map[string][]net.IP{
 				"hosta": {{1, 1, 1, 1}, {2, 2, 2, 2}},
 				"hostb": {{3, 3, 3, 3}, {4, 4, 4, 4}},
@@ -130,7 +152,7 @@ func Test_Updater_GetServers(t *testing.T) {
 
 			presolver := common.NewMockParallelResolver(ctrl)
 			if testCase.expectResolve {
-				presolver.EXPECT().Resolve(ctx, testCase.hostsToResolve, testCase.minServers).
+				presolver.EXPECT().Resolve(ctx, testCase.resolveSettings).
 					Return(testCase.hostToIPs, testCase.resolveWarnings, testCase.resolveErr)
 			}
 

internal/provider/ivpn/updater/updater.go

@@ -12,10 +12,11 @@ type Updater struct {
 	warner    common.Warner
 }
 
-func New(client *http.Client, warner common.Warner) *Updater {
+func New(client *http.Client, warner common.Warner,
+	parallelResolver common.ParallelResolver) *Updater {
 	return &Updater{
 		client:    client,
-		presolver: newParallelResolver(),
+		presolver: parallelResolver,
 		warner:    warner,
 	}
 }