Feat: healthcheck uses ping instead of DNS

internal/healthcheck/server.go

@@ -2,7 +2,6 @@ package healthcheck
 
 import (
 	"context"
-	"net"
 
 	"github.com/qdm12/gluetun/internal/configuration"
 	"github.com/qdm12/gluetun/internal/vpn"
@@ -16,20 +15,20 @@ type ServerRunner interface {
 }
 
 type Server struct {
-	logger   logging.Logger
-	handler  *handler
-	resolver *net.Resolver
-	config   configuration.Health
-	vpn      vpnHealth
+	logger  logging.Logger
+	handler *handler
+	pinger  Pinger
+	config  configuration.Health
+	vpn     vpnHealth
 }
 
 func NewServer(config configuration.Health,
 	logger logging.Logger, vpnLooper vpn.Looper) *Server {
 	return &Server{
-		logger:   logger,
-		handler:  newHandler(logger),
-		resolver: net.DefaultResolver,
-		config:   config,
+		logger:  logger,
+		handler: newHandler(logger),
+		pinger:  newPinger(),
+		config:  config,
 		vpn: vpnHealth{
 			looper:      vpnLooper,
 			healthyWait: config.VPN.Initial,