S3 Wrapper

s3.py

#!/usr/bin/env python
import threading
import contextlib as ctx
import boto.s3 as s3

storage_info = threading.local()

DEFAULT_REGION = 'us-east-1'

@ctx.contextmanager
def storage(key_name):
    global storage_info
    try:
        conn = storage_info.s3_conn
        if conn is None:
            raise AttributeError('S3 connection does not exist')
    except AttributeError:
        conn = s3.connect_to_region(
            DEFAULT_REGION,
            aws_access_key=settings.access_key,
            aws_secret_key=settings.secret_key
        )
        storage_info.s3_conn = conn

    try:
        bucket = storage_info.s3_bucket
        if bucket is None:
            raise AttributeError('Bucket does not exist')
    except AttributeError:
        bucket = conn.get_bucket(settings.bucket_name, validate=False)
        storage_info.s3_bucket = bucket

    key = bucket.get_key(key_name, validate=False)
    
    yield key
    
    # Do some cleanup after use


filename = 'linkshare/somefile.csv'

# Reading
with storage(filename) as key:
    key.open_read()

# Writing
with storage(filename) as key:
    key.set_contents_from_stream(blah)