Update lambda_function.py

EC2/Stopping-EC2-Instances-Nightly/lambda_function.py

@@ -1,25 +1,29 @@
-import boto3
+import boto3 #library used to create ec2_client object to interact with EC2 INSTANCES INSIDE OF AWS
 
 
 def lambda_handler(event, context):
 
     # Get list of regions
     ec2_client = boto3.client('ec2')
     regions = [region['RegionName']
+               # retrieves a list of available AWS regions by calling ec2_client.describe_regions(). The response is a dictionary containing information about the regions. The code extracts the region names and stores them inside of the regions list
                for region in ec2_client.describe_regions()['Regions']]
 
     # Iterate over each region
     for region in regions:
+        #creates an EC2 resource object (ec2) for the current region using boto3.resource('ec2', region_name=region).
         ec2 = boto3.resource('ec2', region_name=region)
-
+        #prints the current region to the console 
         print("Region:", region)
 
-        # Get only running instances
+        #code filters the EC2 instances in the current region to get only the running instances. 
+        #It uses ec2.instances.filter() and specifies a filter to include instances with the state 'running'
         instances = ec2.instances.filter(
             Filters=[{'Name': 'instance-state-name',
                       'Values': ['running']}])
 
         # Stop the instances
         for instance in instances:
             instance.stop()
+            #prints the id of each stopped instance 
             print('Stopped instance: ', instance.id)