fix(metrics): stabilize query cache and add weekly warm cron

  * Use fixed UTC date bounds for metrics intervals so cache keys stay stable across the week
  * Expose created_at on the API
  * Align the dashboard with the email window, and warm the cache after the Saturday metrics email.

  Closes #1940

Signed-off-by: Alan Peixinho <alan.peixinho@profusion.mobi>

fix: change seeds to include older timestamp

Signed-off-by: Alan Peixinho <alan.peixinho@profusion.mobi>

Author: alanpeixinho

backend/kernelCI/settings.py

@@ -227,6 +227,10 @@ def get_json_env_var(name, default):
                 "--monitoring-id=delete_unused_hardware_status",
             ],
         ),
+        (
+            "10 0 * * 6",
+            "kernelCI_app.queries.notifications.warm_metrics_cache",
+        ),
         (
             "0 0 * * 6",
             "django.core.management.call_command",

backend/kernelCI_app/constants/localization.py

@@ -71,10 +71,10 @@ class DocStrings:
     )
     DEFAULT_INTERVAL_DESCRIPTION = "Interval in days for the listing"
     METRICS_START_DAYS_AGO_DESCRIPTION = (
-        "Number of days ago that marks the start of the metrics interval"
+        "Inclusive UTC day offset for the start of a [start, end) metrics interval"
     )
     METRICS_END_DAYS_AGO_DESCRIPTION = (
-        "Number of days ago that marks the end of the metrics interval"
+        "Exclusive UTC day offset for the end of a [start, end) metrics interval"
     )
     DEFAULT_LISTING_STARTING_DATE_DESCRIPTION = (
         "Starting date to calculate the search interval."

backend/kernelCI_app/management/commands/notifications.py

@@ -1,7 +1,7 @@
 import json
 import sys
 from collections import defaultdict
-from datetime import datetime, timedelta, timezone
+from datetime import datetime, time, timedelta, timezone
 from email.utils import make_msgid
 from types import SimpleNamespace
 from typing import Optional
@@ -38,6 +38,7 @@
 from kernelCI_app.queries.notifications import (
     get_checkout_summary_data,
     get_metrics_data,
+    interval_params,
     kcidb_build_incidents,
     kcidb_issue_details,
     kcidb_last_build_without_issue,
@@ -847,8 +848,14 @@ def generate_metrics_report(
         return
 
     now = datetime.now(timezone.utc)
-    start_datetime = now - timedelta(days=start_days_ago)
-    end_datetime = now - timedelta(days=end_days_ago)
+    bounds = interval_params(start_days_ago, end_days_ago)
+    start_datetime = datetime.fromisoformat(bounds["start_date"])
+    exclusive_end = datetime.fromisoformat(bounds["end_date"])
+    end_datetime = datetime.combine(
+        exclusive_end.date() - timedelta(days=1),
+        time.max,
+        tzinfo=timezone.utc,
+    )
 
     data: MetricsReportData = get_metrics_data(
         start_days_ago=start_days_ago,