ESP8266: add NTP sync timeout

Author: pennam

src/utility/time/TimeService.cpp

@@ -43,6 +43,9 @@ time_t cvt_time(char const * time);
  * CONSTANTS
  **************************************************************************************/
 
+#ifdef ARDUINO_ARCH_ESP8266
+static unsigned long const AIOT_TIMESERVICE_ESP8266_NTP_SYNC_TIMEOUT_ms = 86400000;
+#endif
 static time_t const EPOCH_AT_COMPILE_TIME = cvt_time(__DATE__);
 static time_t const EPOCH = 0;
 
@@ -57,8 +60,9 @@ TimeService::TimeService()
 , _timezone_offset(0)
 , _timezone_dst_until(0)
 #ifdef ARDUINO_ARCH_ESP8266
-, _soft_rtc_value(0)
-, _soft_rtc_offset(0)
+, _last_ntp_sync_tick(0)
+, _last_rtc_update_tick(0)
+, _rtc(0)
 #endif
 {
 
@@ -110,19 +114,27 @@ unsigned long TimeService::getTime()
   }
   return time(NULL);
 #elif ARDUINO_ARCH_ESP8266
-  if(!_is_rtc_configured || millis() < _soft_rtc_offset)
+  unsigned long const now = millis();
+  bool const is_ntp_sync_timeout = (now - _last_ntp_sync_tick) > AIOT_TIMESERVICE_ESP8266_NTP_SYNC_TIMEOUT_ms;
+  if(!_is_rtc_configured || is_ntp_sync_timeout)
   {
     _is_rtc_configured = false;
     unsigned long utc = getRemoteTime();
     if(EPOCH_AT_COMPILE_TIME != utc)
     {
-      _soft_rtc_value = utc;
-      _soft_rtc_offset = millis();
+      _rtc = utc;
+      _last_ntp_sync_tick = now;
+      _last_rtc_update_tick = now;
       _is_rtc_configured = true;
     }
     return utc;
   }
-  return _soft_rtc_value + ((millis() - _soft_rtc_offset) / 1000);
+  unsigned long const elapsed_s = (now - _last_rtc_update_tick) / 1000;
+  if(elapsed_s) {
+    _rtc += elapsed_s;
+    _last_rtc_update_tick = now;
+  }
+  return _rtc;
 #else
   return getRemoteTime();
 #endif

src/utility/time/TimeService.h

@@ -61,8 +61,9 @@ class TimeService
   long _timezone_offset;
   unsigned long _timezone_dst_until;
 #ifdef ARDUINO_ARCH_ESP8266
-  unsigned long _soft_rtc_value;
-  unsigned long _soft_rtc_offset;
+  unsigned long _last_ntp_sync_tick;
+  unsigned long _last_rtc_update_tick;
+  unsigned long _rtc;
 #endif
 
   unsigned long getRemoteTime();