import os
ACCESS_KEY_ID = os.environ['ACCESS_KEY_ID']
SECRET_ACCESS_KEY = os.environ['SECRET_ACCESS_KEY']

import boto

def list_all_buckets(s3):
    buckets = s3.get_all_buckets()
    return buckets

# SNIP
def main():
    s3 = boto.connect_s3(
        host='s3.amazonaws.com',
        aws_access_key_id=ACCESS_KEY_ID,
        aws_secret_access_key=SECRET_ACCESS_KEY)
    buckets = list_all_buckets(s3)
# SNAP
    
    for bucket in buckets:
        print("First objects from bucket '{}' in location {}:".
            format(bucket.name, bucket.get_location()))
        for i, obj in enumerate(bucket.list()):
            if i > 3:
                break
            print("  {}".format(repr(obj)))

main()