From 7ad4d97b0372b9c78e3081851f0db2d63ee0e10f Mon Sep 17 00:00:00 2001
From: Guslington <guslington@gmail.com>
Date: Wed, 3 Aug 2022 12:55:05 +1000
Subject: [PATCH] alarm to monitor total file size of an efs volume

---
 lib/cfnguardian/models/alarm.rb                  |  5 ++++-
 lib/cfnguardian/resources/elastic_file_system.rb | 12 ++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/cfnguardian/models/alarm.rb b/lib/cfnguardian/models/alarm.rb
index bb13fa7..cd94554 100644
--- a/lib/cfnguardian/models/alarm.rb
+++ b/lib/cfnguardian/models/alarm.rb
@@ -299,11 +299,14 @@ def initialize(resource)
     end
     
     class ElasticFileSystemAlarm < BaseAlarm
-      def initialize(resource)
+      def initialize(resource, storage_class = nil)
         super(resource)
         @group = 'ElasticFileSystem'
         @namespace = 'AWS/EFS'
         @dimensions = { FileSystemId: resource['Id'] }
+        unless storage_class.nil?
+          @dimensions[:StorageClass] = storage_class
+        end
       end
     end
     
diff --git a/lib/cfnguardian/resources/elastic_file_system.rb b/lib/cfnguardian/resources/elastic_file_system.rb
index 968fb64..c7198b8 100644
--- a/lib/cfnguardian/resources/elastic_file_system.rb
+++ b/lib/cfnguardian/resources/elastic_file_system.rb
@@ -22,6 +22,18 @@ def default_alarms
         alarm.treat_missing_data = 'notBreaching'
         alarm.datapoints_to_alarm = 5
         @alarms.push(alarm)
+
+        alarm = CfnGuardian::Models::ElasticFileSystemAlarm.new(@resource, 'Total')
+        alarm.name = 'TotalStorageUsed'
+        alarm.metric_name = 'StorageBytes'
+        alarm.comparison_operator = 'GreaterThanThreshold'
+        alarm.threshold = 10000000000 # 10GB default
+        alarm.evaluation_periods = 60
+        alarm.treat_missing_data = 'notBreaching'
+        alarm.datapoints_to_alarm = 30
+        alarm.alarm_action = 'Task'
+        alarm.enabled = false
+        @alarms.push(alarm)
       end
     end
   end