add missing import; remove outdated comment; reformat grouping message

src/robusta/integrations/slack/sender.py

@@ -1,6 +1,7 @@
 import logging
 import ssl
 import tempfile
+import time
 from datetime import datetime
 from itertools import chain
 from typing import Any, Dict, List, Set, Tuple
@@ -415,15 +416,16 @@ def send_or_update_summary_message(
     ):
         """Create or update a summary message with tabular information about the amount of events
         fired/resolved and a header describing the event group that this information concerns."""
-        # TODO investigate button
+        now_ts = time.time()
+
         rows = []
+        n_total_alerts = 0
         for key, value in sorted(summary_table.items()):
             # key is a tuple of attribute names; value is a 2-element list with
-            # the number of firing and resolved events.
+            # the number of firing and resolved notifications.
             row = list(str(e) for e in chain(key, value))
             rows.append(row)
-
-        now_ts = time.time()
+            n_total_alerts += value[0] + value[1]  # count firing and resolved notifications
 
         table_block = TableBlock(headers=finding_summary_header + ["Fired", "Resolved"], rows=rows)
         summary_start_utc_dt = datetime.fromtimestamp(summary_start).astimezone(tz.UTC)
@@ -434,8 +436,11 @@ def send_or_update_summary_message(
             f"*Group time range:* <!date^{int(summary_start)}^{{date_num}} {{time}}|{formatted_summary_start}>"
             f" to <!date^{int(now_ts)}^{{date_num}} {{time}}|{formatted_now_ts}>"
         )
+        group_by_criteria_str = ", ".join(f"`header`" for header in group_by_classification_header)
         blocks = [
-            MarkdownBlock("👀 Group summary for " + ", ".join(group_by_classification_header)),
+            MarkdownBlock("👀 Alert summary"),
+            MarkdownBlock(f"Total alerts: {n_total_alerts}"),
+            MarkdownBlock(f"Matching criteria: {group_by_criteria_str}"),
             LinksBlock(
                 links=[
                     LinkProp(