<p>Have you ever wanted to have persistent storage for your Heroku app because ephemeral storage was <em>just not cutting it?</em></p>

<div style="text-align: center;">
    <img src="/assets/images/articles/cloudcube.png" class="img-bordered">
</div>
<p><a href="https://elements.heroku.com/addons/cloudcube">Cloudcube</a> is a storage addon that gives you an S3 bucket with
a 5mb limit in the free tier. Fairly generous! This is great because by default Heroku apps are ephemeral (storage
is deleted when a new version is deployed).</p>
<h3>Heroku</h3>
<p>Install the <a href="https://elements.heroku.com/addons/cloudcube">add on</a> for your Heroku app, or if you're using
<a href="https://devcenter.heroku.com/articles/github-integration-review-apps">Review apps</a> then you'll
want to add <code>"cloudcube:free"</code> to your <code>addons</code> key in <code>app.json</code>:</p>
<pre><code class="language-json">{
  "addons": [
    "cloudcube:free"
  ],
}
</code></pre>
<h3>Django/Python</h3>
<p>Make sure you install <code>django-storages</code> and <code>boto3</code>:</p>
<pre><code class="language-bash">$ pip install django-storages boto3
</code></pre>
<pre><code class="language-python"># settings/base.py
import os

# =============================================================================
# Cloudcube storage
# =============================================================================
DEFAULT_FILE_STORAGE = 'storages.backends.s3boto3.S3Boto3Storage'

# example cloudcube url: https://cloud-cube.s3.amazonaws.com/bucketname
cloudcube_url = os.environ.get('CLOUDCUBE_URL')
cloudcube_bucket = os.path.basename(cloudcube_url)   # "bucketname"
cloudcube_base_url = os.path.dirname(cloudcube_url)  # "https://cloud-cube.s3.amazonaws.com/" 

AWS_S3_ENDPOINT_URL = cloudcube_base_url
AWS_ACCESS_KEY_ID = os.environ.get('CLOUDCUBE_ACCESS_KEY_ID')
AWS_SECRET_ACCESS_KEY = os.environ.get('CLOUDCUBE_SECRET_ACCESS_KEY')
AWS_STORAGE_BUCKET_NAME = cloudcube_bucket
AWS_DEFAULT_ACL = os.environ.get('AWS_DEFAULT_ACL', 'private')
AWS_QUERYSTRING_AUTH = False
AWS_S3_SIGNATURE_VERSION = "s3v4"
</code></pre>
<p>We want everything by default to be private, so we've set the <code>AWS_DEFAULT_ACL</code> setting
to <code>"private"</code>. If we want to override this private setting, we can subclass
<code>S3Boto3Storage</code> and change the setting.</p>
<p>For example, static file storage or user image uploads should be public. We'll
want to use a <code>"public-read"</code> setting.</p>
<p>Example demonstrating public and private styles:</p>
<pre><code class="language-python"># custom settings class in yourapp/storages.py
from django.core.files.storage import get_storage_class


class PublicStorage(get_storage_class()):
    default_acl = 'public-read'
    

class PrivateStorage(Storage):
    """When you call file.url using this storage, URLs are automatically appended with
    SAS (Signed Access Signature) parameters."""
    default_acl = 'private'
    secure_urls = True
    querystring_auth = True


# static files in settings/base.py
STATICFILES_STORAGE = 'yourapp.storages.PublicStorage'


# image uploads in someapp/models.py
from yourapp.storages import PublicStorage
class MyModel(models.Model):
    logo = models.ImageField(upload_to='logos', storage=PublicStorage())
    private_upload = models.FileField(upload_to='private', storage=PrivateStorage())
</code></pre>
<div style="text-align: center;">
    <img src="/assets/images/articles/cloudcube_screenshots.png" class="img-bordered"><br>
    <small><i>CloudCube interface</i></small>
</div>
<h3>Conclusion</h3>
<p>Thanks CloudCube folks for giving us free persistent storage! 5mb aint much, but it
allows us to give our clients an easy place to upload small CSVs at least. If we need
to test more, $5/mo for 5gb aint bad!</p>
<p>..although, it would be neat to have a $1/mo 100mb tier :)</p>

CloudCube (S3) in Django on Heroku