Using ImageMagick to generate thumbnails for images stored in Amazon S3

Question

I'm looking to use ImageMagick's convert utility to make thumbnails for images stored in S3. I'm writing this in Python.

How should I approach this?

Should I read the image from S3, save it to a temporary folder on an EC2 instance, generate the thumbnail to a temporary directory, then put the temporary file into S3 and delete it?

Or can I "pipe" the result from S3 right into ImageMagick without storing it to local disk?

Is there a recommended way to do this?

Thanks in advance.

Answer 1

You can use subprocess with file objects and directly pipe them to imagemagick. For example here I convert directly an online png to a jpg without using temporary files.

import subprocess
import urllib2
import sys 
source = urllib2.urlopen('http://cdn.sstatic.net/stackoverflow/img/apple-touch-icon.png')
p = subprocess.Popen(['convert','png:-', 'jpg:-'], stdin=source, stdout=subprocess.PIPE)
p.communicate()[0] # this is your converted image