network enhanecment / refactor (#361)

* chore(network): improve connectivity check

* refactor(network): rewrite network and timesync component

* feat(display): show cloud connection status

* chore: change logging verbosity

* chore(websecure): update log message

* fix(ota): validate root certificate when downloading update

* feat(ui): add network settings tab

* fix(display): cloud connecting animation

* fix: golintci issues

* feat: add network settings tab

* feat(timesync): query servers in parallel

* refactor(network): move to internal/network package

* feat(timesync): add metrics

* refactor(log): move log to internal/logging package

* refactor(mdms): move mdns to internal/mdns package

* feat(developer): add pprof endpoint

* feat(logging): add a simple logging streaming endpoint

* fix(mdns): do not start mdns until network is up

* feat(network): allow users to update network settings from ui

* fix(network): handle errors when net.IPAddr is nil

* fix(mdns): scopedLogger SIGSEGV

* fix(dhcp): watch directory instead of file to catch fsnotify.Create event

* refactor(nbd): move platform-specific code to different files

* refactor(native): move platform-specific code to different files

* chore: fix linter issues

* chore(dev_deploy): allow to override PION_LOG_TRACE

timesync.go

@@ -0,0 +1,53 @@
+package kvm
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/jetkvm/kvm/internal/timesync"
+)
+
+var (
+	timeSync       *timesync.TimeSync
+	builtTimestamp string
+)
+
+func isTimeSyncNeeded() bool {
+	if builtTimestamp == "" {
+		timesyncLogger.Warn().Msg("built timestamp is not set, time sync is needed")
+		return true
+	}
+
+	ts, err := strconv.Atoi(builtTimestamp)
+	if err != nil {
+		timesyncLogger.Warn().Str("error", err.Error()).Msg("failed to parse built timestamp")
+		return true
+	}
+
+	// builtTimestamp is UNIX timestamp in seconds
+	builtTime := time.Unix(int64(ts), 0)
+	now := time.Now()
+
+	if now.Sub(builtTime) < 0 {
+		timesyncLogger.Warn().
+			Str("built_time", builtTime.Format(time.RFC3339)).
+			Str("now", now.Format(time.RFC3339)).
+			Msg("system time is behind the built time, time sync is needed")
+		return true
+	}
+
+	return false
+}
+
+func initTimeSync() {
+	timeSync = timesync.NewTimeSync(&timesync.TimeSyncOptions{
+		Logger:        timesyncLogger,
+		NetworkConfig: config.NetworkConfig,
+		PreCheckFunc: func() (bool, error) {
+			if !networkState.IsOnline() {
+				return false, nil
+			}
+			return true, nil
+		},
+	})
+}