Add event/update counter to metrics

mautrix_telegram/matrix.py

@@ -29,13 +29,17 @@ if TYPE_CHECKING:
     from .context import Context
 
 try:
-    from prometheus_client import Histogram
+    from prometheus_client import Histogram, Counter
 
+    EVENT_COUNT = Counter("matrix_event_count", "Number of Matrix events processed",
+                          ["event_type"])
     EVENT_TIME = Histogram("matrix_event", "Time spent processing Matrix events",
                            ["event_type"])
 except ImportError:
     Histogram = None
     EVENT_TIME = None
+    EVENT_COUNT = None
+
 
 class MatrixHandler:
     log = logging.getLogger("mau.mx")  # type: logging.Logger
@@ -442,5 +446,6 @@ class MatrixHandler:
             await self.handle_typing(room_id, content.get("user_ids", []))
         else:
             return
-        if EVENT_TIME:
+        if EVENT_TIME and EVENT_COUNT:
             EVENT_TIME.labels(event_type=evt_type).observe(time.time() - start_time)
+            EVENT_COUNT.labels(event_type=evt_type).inc()