Compress S3 Images using Boto3

compress_s3_images.py

import sys, botocore

import boto3
from io import BytesIO
from PIL import Image as pil

def start_compressing(dry_run=False):
    s3 = boto3.resource('s3')
    bucket = s3.Bucket('mybucketname')
    exists = True
    try:
        s3.meta.client.head_bucket(Bucket='mybucketname')
    except botocore.exceptions.ClientError as e:
        # If a client error is thrown, then check that it was a 404 error.
        # If it was a 404 error, then the bucket does not exist.
        error_code = int(e.response['Error']['Code'])
        if error_code == 404:
            exists = False

    i = 0
    for file in bucket.objects.all():
        if file.key[-4:] == '.jpg' or file.key[-4:] == '.png':
            if file.size > 150000:
                if not dry_run:
                    compress_image(file, i)
                i += 1

    if dry_run:
       print('Will compress {0} images'.format(i))
    else:
       print('Compressed {0} images'.format(i))


def compress_image(pic, index):
    print('{0}: compressing image: {1}'.format(index, pic.key))
    input_file = BytesIO(pic.get()['Body'].read())
    img = pil.open(input_file)
    tmp = BytesIO()
    img.save(tmp, 'JPEG', quality=50)
    tmp.seek(0)
    output_data = tmp.getvalue()

    content_type = 'image/jpeg'
    content_length = len(output_data)
    cache_control  = 'max-age = 604800'

    pic.put(Body=output_data, CacheControl=cache_control, ContentLength=content_length, ContentType=content_type, ServerSideEncryption='AES256', ACL='public-read')

    tmp.close()
    input_file.close()

if __name__ == "__main__":
    if len(sys.argv) > 1:
        command = sys.argv[1]
        if command == 'dry_run':
            start_compressing(dry_run=True)
        else:
            print('Invalid command. For a dry run please run: python compress_s3_images.py dry_run')
    else:
        start_compressing()
    print("end")
    sys.exit()

Derived from this boto (2.x) gist @rigoneri