s3-bucket

An easy to use client for S3


License
MIT
Install
pip install s3-bucket==1.4.0

Documentation

CodeLighthouse's Python AWS S3 Client

Welcome to CodeLighthouse's official documentation for our python AWS S3 client! If you're looking for guidance on how to install, configure, and use the S3 client, you're in the right place!

The S3 Client is designed to provide many of the high-level functionalities of Amazon's botocore's S3 resource, without forcing users to decipher botocore's arcane documentation or deal with low-level configuration.

Overview

Amazon Web Services' botocore API is extremely low-level, and it can be extremely difficult to work with. AWS S3 (Simple Storage Service) is not complicated - it's object storage. You can GET, PUT, DELETE, and COPY objects, with a few other functionalities. Simple, right? Yet for some reason, if you were to print botocore's documentation for the S3 service, you'd come out to about 525 printed pages.

To develop with S3 faster, we wrote a Python package to abstract away a lot of the overhead and configuration that's required, so that you can focus on developing with S3 faster. Note that this package provides a high-level API that does not allow for some types of low-level management.

Getting Started

Installing with pip

Our S3 client is hosted on PyPi, so it couldn't be easier to install:

pip install s3-bucket

Configuring the S3 Client

Once you've installed the S3 client, you'll need to configure it with your AWS access key ID and your AWS secret access key. We strongly suggest not hard-coding these values in your code, since doing so can create security vulnerabilities, and is bad practice. Instead, we recommend storing them in environment variables and using the os module to fetch them:

import s3_bucket as S3
import os

# get your key data from environment variables
AWS_ACCESS_KEY_ID = os.environ.get('AWS_ACCESS_KEY_ID')
AWS_SECRET_ACCESS_KEY = os.environ.get('AWS_SECRET_ACCESS_KEY')

# initialize the package
S3.Bucket.prepare(AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY)

Temporary AWS Credentials

If you're using temporary credentials (i.e. AWS STS) you'll need to pass in your session token as well:

import s3_bucket as S3
import os

# get your key data from environment variables
AWS_ACCESS_KEY_ID = os.environ.get('AWS_ACCESS_KEY_ID')
AWS_SECRET_ACCESS_KEY = os.environ.get('AWS_SECRET_ACCESS_KEY')
AWS_SESSION_TOKEN = os.environ.get('AWS_SESSION_TOKEN')

# initialize the package
S3.Bucket.prepare(AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, AWS_SESSION_TOKEN)

Using the S3 Client

The S3 Client API is designed to be logically similar to how AWS structures S3 buckets. Instead of using botocore's Resource, Session, Client, and Object APIs, there is one, simple API: the Bucket API.

The Bucket API

The Bucket API is simple, and provides most basic methods you'd want to use for an S3 bucket. Once you've initialized the S3 client with the keys as described in the previous section, you can initialize a Bucket object by passing it a bucket name:

bucket = S3.Bucket('your bucket name')

#example
bucket = S3.Bucket('my-website-data')

Once you've done that, it's smooth sailing - you can use any of the following methods:

Method Description
bucket.get(key) returns a two-tuple containing the bytes of the object and a Dict containing the object's metadata
bucket.put(key, data, metadata=metadata) upload data as an object with key as the object's key. data can be either a str type or a bytes type. metadata is an optional argument that should be a Dict containing metadata to store with the object.
bucket.delete(key) delete the object in the bucket specified by key
bucket.upload_file(local_filepath, key) Upload the file specified by local_filepath to the bucket with key as the object's key.
bucket.download_file(key, local_filepath) Download the object specified by key from the bucket and store it in the local file local_filepath.

Custom Exceptions

As I mentioned earlier, the way that botocore raises exceptions is somewhat arcane. Instead of raising different types of exceptions to indicate different types of problems, it throws one type of exception that contains properties that you must use to determine what went wrong. It's really obtuse, and a bad design pattern.

Instead of relying on your client code to decipher botocore's exceptions, I wrote custom exception classes that you can use to handle most common types of S3 errors.

Exception Cause Properties
BucketException The super class for all other Bucket exceptions. Can be used to generically catch other exceptions raised by the API. bucket, message
NoSuchBucket Raised if you try to access a bucket that does not exist. bucket, message
NoSuchKey Raised if you try to access an object that does not exist within an existing bucket. bucket, key, message
BucketAccessDenied AWS denied access to the bucket you tried to access. It may not exist, or you may not have permission to access it. bucket, message
UnknownBucketException Botocore threw an exception which this client was not programmed to handle. bucket, error_code, error_message

To use these exceptions, you can do the following:

try:
	bucket = S3.Bucket('my-bucket-name') 
	data, metadata = bucket.get('some key')
except S3.Exceptions.NoSuchBucket as e:
	# some error handling here
	pass

Examples

Below we've provided some examples of common use cases for the S3 Client.

Uploading and downloading files

This example shows how to upload and download files to/from your S3 bucket

import s3_bucket as S3
import os

# get your key data from environment variables
AWS_ACCESS_KEY_ID = os.environ.get('AWS_ACCESS_KEY_ID')
AWS_SECRET_ACCESS_KEY = os.environ.get('AWS_SECRET_ACCESS_KEY')

# initialize the package
S3.Bucket.prepare(AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY)

# initialize a bucket
my_bucket = S3.Bucket('my-bucket')

# UPLOAD A FILE
my_bucket.upload_file('/tmp/file_to_upload.txt', 'myfile.txt')
my_bucket.download_file('myfile.txt', '/tmp/destination_filename.txt')

Storing and retrieving large blobs of text

The reason that we originally built this client was to handle storing and retrieving large blobs of JSON data that were way to big to store in my database. The below example shows you how to do that.

import s3_bucket as S3
import os

# get your key data from environment variables
AWS_ACCESS_KEY_ID = os.environ.get('AWS_ACCESS_KEY_ID')
AWS_SECRET_ACCESS_KEY = os.environ.get('AWS_SECRET_ACCESS_KEY')

# initialize the package
S3.Bucket.prepare(AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY)
# initialize a bucket
my_bucket = S3.bucket('my-bucket')

# some json string
my_json_str = "{'a': 1, 'b': 2}" # an example json string

my_bucket.put('json_data_1', my_json_str)

data, metadata = my_bucket.get('json_data_1')