log when runner is behind

src/dexorder/runner.py

@@ -213,6 +213,7 @@ class BlockStateRunner(BlockProgressor):
 
 
     async def worker(self):
+        was_behind = False
         try:
             log.info(f'Runner started')
             w3 = current_w3.get()
@@ -263,6 +264,14 @@ class BlockStateRunner(BlockProgressor):
                     else:
                         log.info(f'Reverting {fork.branch} due to {e}') # runtime exception like SystemExit
                     self.state.remove_branch(fork.branch)
+                processed_block = await get_block(fork.head)
+                behind = timestamp() - processed_block.timestamp
+                if behind > 2:
+                    # todo pagerduty alerts if too far behind
+                    log.info(f'Runner is {timedelta(seconds=behind)} behind')
+                    was_behind = True
+                elif was_behind:
+                    log.info('Runner has caught up')
         except Exception as e:
             fatal('Unhandled exception in runner worker', exception=e)
         finally: