add Lambda function to stop EC2 after 30 min to save costs

code-server-stack.yaml

@@ -1,7 +1,3 @@
-#------------------------------------------------------
-# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
-# SPDX-License-Identifier: MIT-0 
-#------------------------------------------------------
 AWSTemplateFormatVersion: "2010-09-09"
 Description: deploy a vscode-server on an ec2 
 #------------------------------------------------------
@@ -263,6 +259,100 @@ Resources:
           ViewerProtocolPolicy: allow-all
           OriginRequestPolicyId: !Ref OriginRequestPolicyId 
           CachePolicyId: !Ref VSCodeServerCloudFrontCachePolicy 
+#--------------------
+# Lambda function resources
+#--------------------
+  LambdaExecutionRole:
+    Type: AWS::IAM::Role
+    Properties:
+      AssumeRolePolicyDocument:
+        Version: '2012-10-17'
+        Statement:
+          - Effect: Allow
+            Principal:
+              Service: lambda.amazonaws.com
+            Action: sts:AssumeRole
+      Policies:
+        - PolicyName: LambdaEC2Policy
+          PolicyDocument:
+            Version: '2012-10-17'
+            Statement:
+              - Effect: Allow
+                Action:
+                  - ec2:DescribeInstances
+                  - ec2:StopInstances
+                Resource: !Sub 'arn:aws:ec2:${AWS::Region}:${AWS::AccountId}:instance/${VSCodeServer}'
+              - Effect: Allow
+                Action:
+                  - cloudwatch:GetMetricStatistics
+                Resource: '*'
+        - PolicyName: LambdaLogsPolicy
+          PolicyDocument:
+            Version: '2012-10-17'
+            Statement:
+              - Effect: Allow
+                Action:
+                  - logs:CreateLogGroup
+                  - logs:CreateLogStream
+                  - logs:PutLogEvents
+                Resource: arn:aws:logs:*:*:*
+
+  IdleEC2CheckerFunction:
+    Type: AWS::Lambda::Function
+    Properties:
+      Handler: index.handler
+      Role: !GetAtt LambdaExecutionRole.Arn
+      Code:
+        ZipFile: |
+          import boto3
+          import datetime
+          import os
+
+          def handler(event, context):
+              ec2 = boto3.client('ec2')
+              cloudwatch = boto3.client('cloudwatch')
+
+              target_instance_id = os.environ['TARGET_INSTANCE_ID']
+
+              # Check CPU utilization for the last 30 minutes
+              response = cloudwatch.get_metric_statistics(
+                  Namespace='AWS/EC2',
+                  MetricName='CPUUtilization',
+                  Dimensions=[{'Name': 'InstanceId', 'Value': target_instance_id}],
+                  StartTime=datetime.datetime.utcnow() - datetime.timedelta(minutes=30),
+                  EndTime=datetime.datetime.utcnow(),
+                  Period=300,
+                  Statistics=['Average']
+              )
+
+              datapoints = response['Datapoints']
+              if datapoints and max(point['Average'] for point in datapoints) <= 10:
+                  print(f"Stopping idle instance: {target_instance_id}")
+                  ec2.stop_instances(InstanceIds=[target_instance_id])
+
+      Runtime: python3.12
+      Timeout: 60
+      Environment:
+        Variables:
+          TARGET_INSTANCE_ID: !Ref VSCodeServer
+
+  ScheduledRule:
+    Type: AWS::Events::Rule
+    Properties:
+      Description: "ScheduledRule"
+      ScheduleExpression: "rate(30 minutes)"
+      State: "ENABLED"
+      Targets: 
+        - Arn: !GetAtt IdleEC2CheckerFunction.Arn
+          Id: "TargetFunctionV1"
+
+  PermissionForEventsToInvokeLambda: 
+    Type: AWS::Lambda::Permission
+    Properties: 
+      FunctionName: !Ref IdleEC2CheckerFunction
+      Action: "lambda:InvokeFunction"
+      Principal: "events.amazonaws.com"
+      SourceArn: !GetAtt ScheduledRule.Arn
 #------------------------------------------------------
 # Exported output
 #------------------------------------------------------ 

lambda-stop-idle-ec2.yaml

@@ -0,0 +1,101 @@
+AWSTemplateFormatVersion: '2010-09-09'
+Description: 'Lambda function to stop idle EC2 instances'
+
+Parameters:
+  TargetEC2InstanceId:
+    Type: AWS::EC2::Instance::Id
+    Description: The ID of the EC2 instance to monitor for idleness
+
+Resources:
+  LambdaExecutionRole:
+    Type: AWS::IAM::Role
+    Properties:
+      AssumeRolePolicyDocument:
+        Version: '2012-10-17'
+        Statement:
+          - Effect: Allow
+            Principal:
+              Service: lambda.amazonaws.com
+            Action: sts:AssumeRole
+      Policies:
+        - PolicyName: LambdaEC2Policy
+          PolicyDocument:
+            Version: '2012-10-17'
+            Statement:
+              - Effect: Allow
+                Action:
+                  - ec2:DescribeInstances
+                  - ec2:StopInstances
+                Resource: !Sub 'arn:aws:ec2:${AWS::Region}:${AWS::AccountId}:instance/${TargetEC2InstanceId}'
+              - Effect: Allow
+                Action:
+                  - cloudwatch:GetMetricStatistics
+                Resource: '*'
+        - PolicyName: LambdaLogsPolicy
+          PolicyDocument:
+            Version: '2012-10-17'
+            Statement:
+              - Effect: Allow
+                Action:
+                  - logs:CreateLogGroup
+                  - logs:CreateLogStream
+                  - logs:PutLogEvents
+                Resource: arn:aws:logs:*:*:*
+
+  IdleEC2CheckerFunction:
+    Type: AWS::Lambda::Function
+    Properties:
+      Handler: index.handler
+      Role: !GetAtt LambdaExecutionRole.Arn
+      Code:
+        ZipFile: |
+          import boto3
+          import datetime
+          import os
+
+          def handler(event, context):
+              ec2 = boto3.client('ec2')
+              cloudwatch = boto3.client('cloudwatch')
+
+              target_instance_id = os.environ['TARGET_INSTANCE_ID']
+
+              # Check CPU utilization for the last 30 minutes
+              response = cloudwatch.get_metric_statistics(
+                  Namespace='AWS/EC2',
+                  MetricName='CPUUtilization',
+                  Dimensions=[{'Name': 'InstanceId', 'Value': target_instance_id}],
+                  StartTime=datetime.datetime.utcnow() - datetime.timedelta(minutes=30),
+                  EndTime=datetime.datetime.utcnow(),
+                  Period=300,
+                  Statistics=['Average']
+              )
+
+              datapoints = response['Datapoints']
+              if datapoints and max(point['Average'] for point in datapoints) <= 10:
+                  print(f"Stopping idle instance: {target_instance_id}")
+                  ec2.stop_instances(InstanceIds=[target_instance_id])
+
+      Runtime: python3.12
+      Timeout: 60
+      Environment:
+        Variables:
+          TARGET_INSTANCE_ID: !Ref TargetEC2InstanceId
+
+  ScheduledRule:
+    Type: AWS::Events::Rule
+    Properties:
+      Description: "ScheduledRule"
+      ScheduleExpression: "rate(30 minutes)"
+      State: "ENABLED"
+      Targets: 
+        - Arn: !GetAtt IdleEC2CheckerFunction.Arn
+          Id: "TargetFunctionV1"
+
+  PermissionForEventsToInvokeLambda: 
+    Type: AWS::Lambda::Permission
+    Properties: 
+      FunctionName: !Ref IdleEC2CheckerFunction
+      Action: "lambda:InvokeFunction"
+      Principal: "events.amazonaws.com"
+      SourceArn: !GetAtt ScheduledRule.Arn
+