Python program to find the checksum and Etag of a file. Etag is a property of a file in S3 which is similar to checksum

EtagExample.py

import os
import boto
import traceback
from boto.s3.connection import S3Connection


class ETagExample(object):
    def __init__(self):
        self.aws_access_key = "XXXXXXXXX"
        self.aws_secret_key = "XXXXXXXXX"
        self.s3_bucket = "checksum-test"
        self.s3_conn = boto.connect_s3(aws_access_key_id=self.aws_access_key,
                                   aws_secret_access_key=self.aws_secret_key,
                                   calling_format=boto.s3.connection.OrdinaryCallingFormat())

    #Function to calculate the checksum of a local file
    def find_checksum(self, file_name):
        try:
            checksum = hashlib.md5(open(file_name).read()).hexdigest()
            return checksum
        except Exception, e:
            print "Exception occurred while calculating checksum :" + str(e)
            print traceback.print_exc()

    #Function to calculate the Etag of a file in S3
    def find_etag(self, full_key_name):
        try:
            bucket = self.s3_conn.get_bucket(self.s3_bucket)
            key = bucket.new_key(full_key_name)
            s3_etag = key.etag.strip('"').strip("'")
            return s3_etag
        except Exception, e:
            print "Exception occurred while calculating S3 Etag : " + str(e)
            print traceback.print_exc()