lambda_function.py

import json
import urllib.parse
import boto3
import os
print('Loading function')

s3 = boto3.client('s3')
TOPIC_ARN = os.environ['topicARN']

def lambda_handler(event, context):
    #print("Received event: " + json.dumps(event, indent=2))

    # Get the object from the event and show its content type
    bucket = event['Records'][0]['s3']['bucket']['name']
    key = urllib.parse.unquote_plus(event['Records'][0]['s3']['object']['key'], encoding='utf-8')
    try:
        response = s3.get_object(Bucket=bucket, Key=key)
        s3_object_body = response.get('Body')
        content_str = s3_object_body.read().decode()
        print("content String: " + content_str)
        words = len(content_str.split())
        result = "The word count in the "+ key +" file is "+ str(words)
        print(result)
        
        snsClient = boto3.client('sns')
        response = snsClient.publish(
            TopicArn = TOPIC_ARN,
            Subject = 'The word count',
            Message = result
        )
        return result
    except Exception as e:
        print(e)
        print('Error getting object {} from bucket {}. Make sure they exist and your bucket is in the same region as this function.'.format(key, bucket))
        raise e