Amazon Lambda reads S3 bucket information and update IoT Thing's status

gistfile1.txt

import os
import sys
import json

root = os.environ["LAMBDA_TASK_ROOT"]
sys.path.insert(0, root)

import boto3

s3 = boto3.client('s3')
iot = boto3.client('iot-data', region_name='us-east-1')

def lambda_handler (event, context):

  try:
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = event['Records'][0]['s3']['object']['key']
    obj = s3.get_object(Bucket=bucket, Key=key)
    objlist = s3.list_objects(Bucket=bucket)
    payload = {
      "state": {
        "desired": {
          "Count": len(objlist['Contents']),
          "Time": obj['LastModified'].strftime('%Y-%m-%D %H:%M:%S')
        }
      }
    }
    iot.publish(
      topic='$aws/things/s3thing/shadow/update',
      qos=0,
      payload=json.dumps(payload)
    )
  except Exception as e:
    print(e)
    raise e