Want my AWS s3 Bucket to read Name from CloudWatch Event

Question

Currently, I am writing a Lambda function that triggers when a new s3 bucket is created (under my project).
I am using a cloudwatch function which triggers the lambda function. 

I have to pass the whole event to the lambda function as input. What do I do to get my Lambda function so that it can read the bucket's name from the event and assign the name as the value to a string variable?

I am using this code below, I have written it myself, might be some mistakes, please correct me where I am lacking and I need to do to accomplish the task that I have mentioned above, thanks in advance and yeah now take a look at my code below:

import boto3
from botocore.exceptions import ClientError

s3 = boto3.client('s3')  

def lambda_handler(event, context):

    bucket = event['s3']['bucket']['name']

Answer 1

CloudTrail events for S3 bucket level operations have the different format than the other events. Actually, the name of bucket is within a JSON object called requestParameters. Also, the whole event is encapsulated within the Records array.
See CloudTrail Log Event Reference.

A truncated version of CloudTrail event for bucket creation is here, this code below might be able to help you out: 

"eventSource": "s3.amazonaws.com",
"eventName": "CreateBucket",
"userAgent": "signin.amazonaws.com",
"requestParameters": {
    "CreateBucketConfiguration": {
        "LocationConstraint": "aws-region",
        "xmlns": "http://s3.amazonaws.com/doc/2006-03-01/"
    },
    "bucketName": "my-awsome-bucket"
}
Therefore, your code could look something like:

import boto3
from botocore.exceptions import ClientError

s3 = boto3.client('s3')  

def lambda_handler(event, context):
    for record in event['Records']:
        if record['eventName'] == "CreateBucket":
            bucket = record['requestParameters']['bucketName']
            print(bucket)

Answer 2

There is a brief description about cloudwatch
https://docs.aws.amazon.com/awscloudtrail/latest/userguide/cloudtrail-event-reference.html