lambda-function-url-demo.py

import boto3
import json
import base64

#set up ec2 client
#adjust region_name according to your preference
ec2 = boto3.client('ec2', region_name='us-east-1')

def lambda_handler(event, context):
    
    #Uncomment to log the event object in CloudWatch Logs
    # print(event)
    
    payload = parse_slack_payload(event["body"])
    tag_name = 'Env'
    tag_value = payload['text']
    
    #filter instances by tag name and value
    response = ec2.describe_instances(Filters=[{'Name': 'tag:' + tag_name, 'Values': [tag_value]}])
    
    # get the instance id and state of each instance
    instances = [ (instance['Instances'][0]['InstanceId'], instance['Instances'][0]['State']['Name']) 
                   for instance in response['Reservations']
                ]
    #prepare slack message
    slack_message=build_slack_message(instances=instances)
    
    #send response back to Slack
    return { 
        "statusCode": 200, 
        "headers": { "Content-Type": "application/json" }, 
        "body": json.dumps(slack_message)
        }

def parse_slack_payload(data):
    # decode the data using the b64decode function
    decoded_data_raw = base64.b64decode(data).decode('utf-8').split('&')

    decoded_data_formatted={}
    for item in decoded_data_raw:
        data_object = item.split('=')
        decoded_data_formatted[data_object[0]] = data_object[1]
    
    return decoded_data_formatted
    

def build_slack_message(instances):
    
    slack_message = { "blocks": [
        {
			"type": "section",
			"fields": [
				{
					"type": "mrkdwn",
					"text": "*Instance Id*"
				},
				{
					"type": "mrkdwn",
					"text": "*State*"
				}
			]
		} ] 
        
    }
    
    for instance_id, instance_state in instances:
        
        block = { 
            "type": "section", 
            "fields": [ 
                { "type": "mrkdwn", "text": instance_id  }, 
                { "type": "mrkdwn", "text": instance_state } 
            ] 
        }
        
        slack_message["blocks"].append(block)
    
    return slack_message