feat(vpn): rotate filtered servers on internal vpn restarts

- Fix #290

internal/provider/utils/pick_test.go

@@ -1,26 +1,137 @@
 package utils
 
 import (
-	"math/rand"
+	"net/netip"
 	"testing"
 
+	"github.com/qdm12/gluetun/internal/configuration/settings"
+	"github.com/qdm12/gluetun/internal/constants/vpn"
 	"github.com/qdm12/gluetun/internal/models"
 	"github.com/stretchr/testify/assert"
 )
 
-func Test_pickRandomConnection(t *testing.T) {
+func Test_ConnectionPicker_pickConnection(t *testing.T) {
 	t.Parallel()
-	connections := []models.Connection{
-		{Port: 1}, {Port: 2}, {Port: 3}, {Port: 4},
+
+	picker := NewConnectionPicker()
+
+	poolA := []models.Connection{
+		{Port: 1}, {Port: 2}, {Port: 3},
 	}
-	source := rand.NewSource(0)
+	connection := picker.pickConnection(poolA)
+	assert.Equal(t, models.Connection{Port: 1}, connection)
 
-	connection := pickRandomConnection(connections, source)
-	assert.Equal(t, models.Connection{Port: 3}, connection)
-
-	connection = pickRandomConnection(connections, source)
-	assert.Equal(t, models.Connection{Port: 3}, connection)
-
-	connection = pickRandomConnection(connections, source)
+	connection = picker.pickConnection(poolA)
 	assert.Equal(t, models.Connection{Port: 2}, connection)
+
+	connection = picker.pickConnection(poolA)
+	assert.Equal(t, models.Connection{Port: 3}, connection)
+
+	connection = picker.pickConnection(poolA)
+	assert.Equal(t, models.Connection{Port: 1}, connection)
+
+	poolB := []models.Connection{
+		{Port: 10}, {Port: 20},
+	}
+	connection = picker.pickConnection(poolB)
+	assert.Equal(t, models.Connection{Port: 10}, connection)
+
+	connection = picker.pickConnection(poolB)
+	assert.Equal(t, models.Connection{Port: 20}, connection)
+
+	connection = picker.pickConnection(poolB)
+	assert.Equal(t, models.Connection{Port: 10}, connection)
+}
+
+func Test_pickConnection(t *testing.T) {
+	t.Parallel()
+
+	testCases := map[string]struct {
+		connections []models.Connection
+		selection   settings.ServerSelection
+		connection1 models.Connection
+		connection2 models.Connection
+		errMessage  string
+	}{
+		"empty_connections": {
+			errMessage: "no connection to pick from",
+		},
+		"openvpn_cycles": {
+			connections: []models.Connection{
+				{Type: vpn.OpenVPN, Port: 1, Hostname: "one"},
+				{Type: vpn.OpenVPN, Port: 2, Hostname: "two"},
+			},
+			selection: settings.ServerSelection{VPN: vpn.OpenVPN},
+			connection1: models.Connection{
+				Type: vpn.OpenVPN, Port: 1,
+				Hostname: "one",
+			},
+			connection2: models.Connection{
+				Type: vpn.OpenVPN, Port: 2,
+				Hostname: "two",
+			},
+		},
+		"openvpn_endpoint_ip_overrides_cycle_pick": {
+			connections: []models.Connection{
+				{Type: vpn.OpenVPN, Hostname: "one", IP: netip.AddrFrom4([4]byte{1, 1, 1, 1})},
+				{Type: vpn.OpenVPN, Hostname: "two", IP: netip.AddrFrom4([4]byte{2, 2, 2, 2})},
+			},
+			selection: settings.ServerSelection{
+				VPN: vpn.OpenVPN,
+				OpenVPN: settings.OpenVPNSelection{
+					EndpointIP: netip.AddrFrom4([4]byte{9, 9, 9, 9}),
+				},
+			},
+			connection1: models.Connection{
+				Type: vpn.OpenVPN, Hostname: "one",
+				IP: netip.AddrFrom4([4]byte{9, 9, 9, 9}),
+			},
+			connection2: models.Connection{
+				Type: vpn.OpenVPN, Hostname: "two",
+				IP: netip.AddrFrom4([4]byte{9, 9, 9, 9}),
+			},
+		},
+		"wireguard_endpoint_ip_picks_target": {
+			connections: []models.Connection{
+				{Type: vpn.Wireguard, Hostname: "one", IP: netip.AddrFrom4([4]byte{1, 1, 1, 1})},
+				{Type: vpn.Wireguard, Hostname: "two", IP: netip.AddrFrom4([4]byte{2, 2, 2, 2})},
+			},
+			selection: settings.ServerSelection{
+				VPN: vpn.Wireguard,
+				Wireguard: settings.WireguardSelection{
+					EndpointIP: netip.AddrFrom4([4]byte{2, 2, 2, 2}),
+				},
+			},
+			connection1: models.Connection{
+				Type: vpn.Wireguard, Hostname: "two",
+				IP: netip.AddrFrom4([4]byte{2, 2, 2, 2}),
+			},
+			connection2: models.Connection{
+				Type: vpn.Wireguard, Hostname: "two",
+				IP: netip.AddrFrom4([4]byte{2, 2, 2, 2}),
+			},
+		},
+	}
+
+	for name, testCase := range testCases {
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			connPicker := NewConnectionPicker()
+
+			connection, err := pickConnection(testCase.connections,
+				testCase.selection, connPicker)
+			if testCase.errMessage != "" {
+				assert.EqualError(t, err, testCase.errMessage)
+				assert.Equal(t, models.Connection{}, connection)
+				return
+			}
+			assert.NoError(t, err)
+			assert.Equal(t, testCase.connection1, connection)
+
+			connection, err = pickConnection(testCase.connections,
+				testCase.selection, connPicker)
+			assert.NoError(t, err)
+			assert.Equal(t, testCase.connection2, connection)
+		})
+	}
 }