How to use Python boto scripts to manage DreamObjects


Boto is a python library that makes it easier to work with services supporting the Amazon Web Services API, such as DreamObjects. Using boto directly requires a little bit of Python-scripting knowledge, whereas you can use the same library via utilities like boto-rsync.

This article describes a few different examples on how you can use boto with DreamHost. If you’re ready to dig into some boto code, the boto getting started guide is a great place to start. DreamHost’s servers already have boto installed so you can skip that part in the documentation.

Creating a .boto file

Now you have to take your user and secret key and put them into a file named ‘.boto’ in our users home directory. You can do this with the following commands if you substitute your own keys:

echo[Credentials]” >> ~/.boto
echo “aws_access_key_id = 98F3n8qUtWEJ6ZdBYyQy” >> ~/.boto
echo “aws_secret_access_key = p5kptXKQrsQtTNJTYtG7emGYooXkN6Kaza1OV-_s” >> ~/.boto

Example Scripts

Here are some examples of scripts that can be useful for managing your DreamObjects service.

Checking the size of a bucket

# -*- coding: utf-8 -*-
#Programmatically calculate the total size of your bucket, by iterating over all your objects
import  boto
c = boto.connect_s3("ACCESS KEY", "SECRET KEY", host="")
b = c.get_bucket("BUCKET NAME")
s = 0
for o in b.list():
   s += o.size
#show you the file size in Megabytes if it's too small to be legible in Gigabytes.
print str(s * 1.0 / 1024 ** 2) + " MB\n"
#Shows you the file size in Gigabytes
print str(s * 1.0 / 1024 ** 3) + " GB"

Purging a directory from a bucket


Below is a script which removes content from a bucket. Proceed with caution as this will permanently delete your data.


The prefix in the script below can be set to “” to delete all data from a bucket, in the case you wish to remove a bucket that contains data.

import boto

c = boto.connect_s3("ACCESS KEY", "SECRET KEY", host="")
b = c.get_bucket("BUCKET NAME", validate=True)

l = [o for o in b.list(prefix="path/to/directory/to/delete")]
while len(l):
   s = l[0:1000]
   rs = b.delete_keys(s)
   if len(s) == len(rs.deleted):
       l = l[1000:]

Change all object permissions in a bucket

This script changes all permissions in a bucket to either private (private) or public (public-read). Uncomment one of the last two lines for the specific permission you wish to use.

import boto

#Connect to S3
c = boto.connect_s3("ACCESS KEY", "SECRET KEY", host="")
b = c.get_bucket("BUCKET NAME")

for o in b.list():
#       o.set_acl('public-read')
#       o.set_acl('private')

Uploading to a bucket in chunks

If the file you are attempting to upload is too large, it must be uploaded in “chunks”. You can use a client that supports multi-part uploads, or use the boto script below.


This script requires the “FileChunkIO” library. If you wish to use this on a DreamHost server, you will first need to reference the Python documentation setting up a virtualenv, activating it and then running the needed “pip install FileChunkIO” and “pip install boto” commands. If not on a DreamHost server and you have root access, using a virtualenv is optional.

import math, os
import boto
from filechunkio import FileChunkIO

#Connect to S3
c = boto.connect_s3("ACCESS KEY", "SECRET KEY", host="")
b = c.get_bucket("BUCKET NAME")

#file info
source_path ='PATH TO YOUR FILE'
source_size = os.stat(source_path).st_size

#Create a multipart upload request
mp = b.initiate_multipart_upload(os.path.basename(source_path))

#set a chunk size (feel free to change this)
chunk_size = 100000
chunk_count = int(math.ceil(source_size / float(chunk_size)))

#send the file parts using FileChunkIO to create a file-like object
#that points to a certain byte range within the original file. We set
#bytes to never exceed the original file size.
for i in range(chunk_count):
        offset = chunk_size * i
        bytes = min(chunk_size, source_size - offset)
        with FileChunkIO(source_path, 'r', offset=offset,bytes=bytes) as fp:
           mp.upload_part_from_file(fp,part_num=i +1)

#Finish the upload

Additional Examples

How to remove multi-part (MPU) upload data and free up bucket space

For more examples of Python code using DreamObjects, please see Sample Python Code Using DreamObjects.

Did this article answer your questions?

Article last updated .