{
		  "Effect": "Allow",
		  "Action": [
		    "ec2:DescribeSpotPriceHistory",
		    "autoscaling:UpdateAutoScalingGroup",
		    "autoscaling:DescribeAutoScalingGroups"
		  ],
		  "Resource": "*"
		}
			

	
	    	if spot_price > threshold:
			    update_asg(100)  # All On-Demand
			else:
			    update_asg(50)   # Half Spot, Half On-Demand
	    
		

		import boto3
import datetime
import os
import requests

# AWS clients
ec2 = boto3.client('ec2')
asg = boto3.client('autoscaling')

# Configuration from environment variables
INSTANCE_TYPE = os.getenv("INSTANCE_TYPE", "t3.medium")
ASG_NAME = os.getenv("ASG_NAME", "example-asg")
PRICE_THRESHOLD = float(os.getenv("PRICE_THRESHOLD", "0.05"))
AVAILABILITY_ZONE = os.getenv("AZ", "us-east-1a")
SLACK_WEBHOOK = os.getenv("SLACK_WEBHOOK")

def get_latest_spot_price():
    """Fetches the latest Spot price for the specified instance type and AZ."""
    now = datetime.datetime.utcnow()
    prices = ec2.describe_spot_price_history(
        InstanceTypes=[INSTANCE_TYPE],
        ProductDescriptions=['Linux/UNIX'],
        StartTime=now - datetime.timedelta(minutes=15),
        EndTime=now,
        AvailabilityZone=AVAILABILITY_ZONE,
        MaxResults=1
    )
    if prices['SpotPriceHistory']:
        return float(prices['SpotPriceHistory'][0]['SpotPrice'])
    else:
        raise Exception("No Spot price history available.")

def update_asg(on_demand_percent):
    """Updates the ASG with a new On-Demand percentage."""
    response = asg.update_auto_scaling_group(
        AutoScalingGroupName=ASG_NAME,
        MixedInstancesPolicy={
            'InstancesDistribution': {
                'OnDemandPercentageAboveBaseCapacity': on_demand_percent,
                'SpotAllocationStrategy': 'capacity-optimized'
            }
        }
    )
    return response

def send_alert(message):
    """Sends an optional Slack alert."""
    if SLACK_WEBHOOK:
        try:
            requests.post(SLACK_WEBHOOK, json={"text": message})
        except Exception as e:
            print(f"[ERROR] Failed to send Slack alert: {e}")

def lambda_handler(event, context):
    """Main Lambda entry point."""
    try:
        price = get_latest_spot_price()
        print(f"[INFO] Current Spot Price: ${price:.4f}")

        if price > PRICE_THRESHOLD:
            update_asg(100)  # All On-Demand
            msg = (
                f"Spot price is ${price:.4f}, above threshold (${PRICE_THRESHOLD}). "
                f"Switched ASG '{ASG_NAME}' to 100% On-Demand to preserve uptime."
            )
        else:
            update_asg(50)  # 50% Spot, 50% On-Demand
            msg = (
                f"Spot price is ${price:.4f}, below threshold (${PRICE_THRESHOLD}). "
                f"Using 50% Spot in ASG '{ASG_NAME}' for optimized savings."
            )

        print(msg)
        send_alert(msg)

    except Exception as e:
        error_msg = f"[ERROR] {str(e)}"
        print(error_msg)
        send_alert(f"Lambda error in spot_monitor: {str(e)}")