Batch marked as failed event alert for App Insights

This enables an alert that will trigger if one
instance of a log based on the query is returned -
so if the batch_marked_failed event is triggered
once.

https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/monitor_scheduled_query_rules_alert_v2

Author: Harriethw

infrastructure/modules/container-apps/alerts.tf

@@ -0,0 +1,38 @@
+resource "azurerm_monitor_scheduled_query_rules_alert_v2" "failure_event" {
+  count = var.enable_alerting ? 1 : 0
+
+  auto_mitigation_enabled           = false
+  description                       = "An alert triggered by a custom event batch_marked_as_failed logged in code"
+  enabled                           = var.enable_alerting
+  evaluation_frequency              = "PT5M"
+  location                          = var.region
+  name                              = "${var.app_short_name}-batch-failed-alert"
+  resource_group_name               = azurerm_resource_group.main.name
+  scopes                            = [var.app_insights_id]
+  severity                          = 2
+  skip_query_validation             = false
+  target_resource_types             = ["microsoft.insights/components"]
+  window_duration                   = "PT5M"
+  workspace_alerts_storage_enabled  = false
+
+  action {
+    action_groups     = [var.action_group_id]
+  }
+
+  criteria {
+    operator                = "GreaterThan"
+    query                   = <<-QUERY
+      customEvents
+        | where name == "batch_marked_as_failed"
+        | project timestamp, name
+        | project-rename TimeGenerated=timestamp
+      QUERY
+    threshold               = 0
+    time_aggregation_method = "Count"
+
+    failing_periods {
+      minimum_failing_periods_to_trigger_alert = 1
+      number_of_evaluation_periods             = 1
+    }
+  }
+}