Amazon S3

Usage

There is only one supported backend for interacting with Amazon’s S3, S3Boto3Storage, based on the boto3 library.

The legacy S3BotoStorage backend was removed in version 1.9. To continue getting new features you must upgrade to the S3Boto3Storage backend by following the migration instructions.

The minimum required version of boto3 is 1.4.4 although we always recommend the most recent.

Settings

To upload your media files to S3 set:

DEFAULT_FILE_STORAGE = 'storages.backends.s3boto3.S3Boto3Storage'

To allow django-admin collectstatic to automatically put your static files in your bucket set the following in your settings.py:

STATICFILES_STORAGE = 'storages.backends.s3boto3.S3StaticStorage'

If you want to use something like ManifestStaticFilesStorage then you must instead use:

STATICFILES_STORAGE = 'storages.backends.s3boto3.S3ManifestStaticStorage'

There are several different methods for specifying the AWS credentials used to create the S3 client. In the order that S3Boto3Storage searches for them:

  1. AWS_S3_SESSION_PROFILE
  2. AWS_S3_ACCESS_KEY_ID and AWS_S3_SECRET_ACCESS_KEY
  3. AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
  4. The environment variables AWS_S3_ACCESS_KEY_ID and AWS_S3_SECRET_ACCESS_KEY
  5. The environment variables AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY
  6. Use Boto3’s default session
AWS_S3_SESSION_PROFILE
The AWS profile to use instead of AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY. All configuration information other than the key id and secret key is ignored in favor of the other settings specified below.

Note

If this is set, then it is a configuration error to also set AWS_S3_ACCESS_KEY_ID and AWS_S3_SECRET_ACCESS_KEY. AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY are ignored

AWS_S3_ACCESS_KEY_ID or AWS_ACCESS_KEY_ID
Your Amazon Web Services access key, as a string.
AWS_S3_SECRET_ACCESS_KEY or AWS_SECRET_ACCESS_KEY
Your Amazon Web Services secret access key, as a string.
AWS_STORAGE_BUCKET_NAME
Your Amazon Web Services storage bucket name, as a string.
AWS_S3_OBJECT_PARAMETERS (optional, default {})

Use this to set parameters on all objects. To set these on a per-object basis, subclass the backend and override S3Boto3Storage.get_object_parameters.

To view a full list of possible parameters (there are many) see the Boto3 docs for uploading files; an incomplete list includes: CacheControl, SSEKMSKeyId, StorageClass, Tagging and Metadata.

AWS_DEFAULT_ACL (optional; default is None which means the file will be private per Amazon’s defalt)

Use this to set an ACL on your file such as public-read. If not set the file will be private per Amazon’s default. If the ACL parameter is set in AWS_S3_OBJECT_PARAMETERS, then this setting is ignored.

Options such as public-read and private come from the list of canned ACLs.

AWS_QUERYSTRING_AUTH (optional; default is True)
Setting AWS_QUERYSTRING_AUTH to False to remove query parameter authentication from generated URLs. This can be useful if your S3 buckets are public.
AWS_S3_MAX_MEMORY_SIZE (optional; default is 0 - do not roll over)
The maximum amount of memory (in bytes) a file can take up before being rolled over into a temporary file on disk.
AWS_QUERYSTRING_EXPIRE (optional; default is 3600 seconds)
The number of seconds that a generated URL is valid for.
AWS_S3_FILE_OVERWRITE (optional: default is True)
By default files with the same name will overwrite each other. Set this to False to have extra characters appended.
AWS_LOCATION (optional: default is ‘’)
A path prefix that will be prepended to all uploads
AWS_IS_GZIPPED (optional: default is False)
Whether or not to enable gzipping of content types specified by GZIP_CONTENT_TYPES
GZIP_CONTENT_TYPES (optional: default is text/css, text/javascript, application/javascript, application/x-javascript, image/svg+xml)
When AWS_IS_GZIPPED is set to True the content types which will be gzipped
AWS_S3_REGION_NAME (optional: default is None)
Name of the AWS S3 region to use (eg. eu-west-1)
AWS_S3_USE_SSL (optional: default is True)
Whether or not to use SSL when connecting to S3.
AWS_S3_VERIFY (optional: default is None)
Whether or not to verify the connection to S3. Can be set to False to not verify certificates or a path to a CA cert bundle.
AWS_S3_ENDPOINT_URL (optional: default is None)
Custom S3 URL to use when connecting to S3, including scheme. Overrides AWS_S3_REGION_NAME and AWS_S3_USE_SSL. To avoid AuthorizationQueryParametersError error, AWS_S3_REGION_NAME should also be set.
AWS_S3_ADDRESSING_STYLE (optional: default is None)
Possible values virtual and path.
AWS_S3_PROXIES (optional: default is None)
A dictionary of proxy servers to use by protocol or endpoint, e.g.: {‘http’: ‘foo.bar:3128’, ‘http://hostname’: ‘foo.bar:4012’}.

AWS_S3_SIGNATURE_VERSION (optional)

As of boto3 version 1.13.21 the default signature version used for generating presigned urls is still v2. To be able to access your s3 objects in all regions through presigned urls, explicitly set this to s3v4.

Set this to use an alternate version such as s3. Note that only certain regions support the legacy s3 (also known as v2) version. You can check to see if your region is one of them in the S3 region list.

Note

The signature versions are not backwards compatible so be careful about url endpoints if making this change for legacy projects.

Migrating from Boto to Boto3

Migration from the boto-based to boto3-based backend should be straightforward and painless.

The following adjustments to settings are required:

  • Rename AWS_HEADERS to AWS_S3_OBJECT_PARAMETERS and change the format of the key names as in the following example: cache-control becomes CacheControl.
  • Rename AWS_ORIGIN to AWS_S3_REGION_NAME
  • If AWS_S3_CALLING_FORMAT is set to VHostCallingFormat set AWS_S3_ADDRESSING_STYLE to virtual
  • Replace the combination of AWS_S3_HOST and AWS_S3_PORT with AWS_S3_ENDPOINT_URL
  • Extract the region name from AWS_S3_HOST and set AWS_S3_REGION_NAME
  • Replace AWS_S3_PROXY_HOST and AWS_S3_PROXY_PORT with AWS_S3_PROXIES
  • If using signature version s3v4 you can remove S3_USE_SIGV4
  • If you persist urls and rely on the output to use the signature version of s3 set AWS_S3_SIGNATURE_VERSION to s3
  • Update DEFAULT_FILE_STORAGE and/or STATICFILES_STORAGE to storages.backends.s3boto3.S3Boto3Storage

Additionally, you must install boto3. The minimum required version is 1.4.4 although we always recommend the most recent.

Please open an issue on the GitHub repo if any further issues are encountered or steps were omitted.

CloudFront

If you’re using S3 as a CDN (via CloudFront), you’ll probably want this storage to serve those files using that:

AWS_S3_CUSTOM_DOMAIN = 'cdn.mydomain.com'

Warning

Django’s STATIC_URL must end in a slash and the AWS_S3_CUSTOM_DOMAIN must not. It is best to set this variable independently of STATIC_URL.

Keep in mind you’ll have to configure CloudFront to use the proper bucket as an origin manually for this to work.

If you need to use multiple storages that are served via CloudFront, pass the custom_domain parameter to their constructors.

CloudFront Signed Urls

If you want django-storages to generate Signed Cloudfront Urls, you can do so by following these steps:

  • modify settings.py to include:

    AWS_CLOUDFRONT_KEY = os.environ.get('AWS_CLOUDFRONT_KEY', None).encode('ascii')
    AWS_CLOUDFRONT_KEY_ID = os.environ.get('AWS_CLOUDFRONT_KEY_ID', None)
    
  • Generate a CloudFront Key Pair as specified in the AWS Doc to create CloudFront key pairs.

  • Updated ENV vars with the corresponding values:

    AWS_CLOUDFRONT_KEY=-----BEGIN RSA PRIVATE KEY-----
    ...
    -----END RSA PRIVATE KEY-----
    AWS_CLOUDFRONT_KEY_ID=APK....
    

django-storages will now generate signed cloudfront urls

IAM Policy

The IAM policy permissions needed for most common use cases are:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "VisualEditor0",
            "Effect": "Allow",
            "Action": [
                "s3:PutObject",
                "s3:GetObjectAcl",
                "s3:GetObject",
                "s3:ListBucket",
                "s3:DeleteObject",
                "s3:PutObjectAcl"
            ],
            "Principal": {
                "AWS": "arn:aws:iam::example-AWS-account-ID:user/example-user-name"
            },
            "Resource": [
                "arn:aws:s3:::example-bucket-name/*",
                "arn:aws:s3:::example-bucket-name"
            ]
        }
    ]
}

For more information about Principal, please refer to AWS JSON Policy Elements

Storage

Standard file access options are available, and work as expected:

>>> from django.core.files.storage import default_storage
>>> default_storage.exists('storage_test')
False
>>> file = default_storage.open('storage_test', 'w')
>>> file.write('storage contents')
>>> file.close()

>>> default_storage.exists('storage_test')
True
>>> file = default_storage.open('storage_test', 'r')
>>> file.read()
'storage contents'
>>> file.close()

>>> default_storage.delete('storage_test')
>>> default_storage.exists('storage_test')
False

Overriding the default Storage class

You can override the default Storage class and create your custom storage backend. Below provides some examples and common use cases to help you get started. This section assumes you have your AWS credentials configured, e.g. AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY.

To create a storage class using a specific bucket:

from storages.backends.s3boto3 import S3Boto3Storage

class MediaStorage(S3Boto3Storage):
    bucket_name = 'my-media-bucket'

Assume that you store the above class MediaStorage in a file called custom_storage.py in the project directory tree like below:

| (your django project root directory)
| ├── manage.py
| ├── my_django_app
| │   ├── custom_storage.py
| │   └── ...
| ├── ...

You can now use your custom storage class for default file storage in Django settings like below:

DEFAULT_FILE_STORAGE = 'my_django_app.custom_storage.MediaStorage'

Or you may want to upload files to the bucket in some view that accepts file upload request:

import os

from django.views import View
from django.http import JsonResponse

from django_backend.custom_storages import MediaStorage

class FileUploadView(View):
    def post(self, requests, **kwargs):
        file_obj = requests.FILES.get('file', '')

        # do your validation here e.g. file size/type check

        # organize a path for the file in bucket
        file_directory_within_bucket = 'user_upload_files/{username}'.format(username=requests.user)

        # synthesize a full file path; note that we included the filename
        file_path_within_bucket = os.path.join(
            file_directory_within_bucket,
            file_obj.name
        )

        media_storage = MediaStorage()

        if not media_storage.exists(file_path_within_bucket): # avoid overwriting existing file
            media_storage.save(file_path_within_bucket, file_obj)
            file_url = media_storage.url(file_path_within_bucket)

            return JsonResponse({
                'message': 'OK',
                'fileUrl': file_url,
            })
        else:
            return JsonResponse({
                'message': 'Error: file {filename} already exists at {file_directory} in bucket {bucket_name}'.format(
                    filename=file_obj.name,
                    file_directory=file_directory_within_bucket,
                    bucket_name=media_storage.bucket_name
                ),
            }, status=400)

A side note is that if you have AWS_S3_CUSTOM_DOMAIN setup in your settings.py, by default the storage class will always use AWS_S3_CUSTOM_DOMAIN to generate url.

If your AWS_S3_CUSTOM_DOMAIN is pointing to a different bucket than your custom storage class, the .url() function will give you the wrong url. In such case, you will have to configure your storage class and explicitly specify custom_domain as below:

class MediaStorage(S3Boto3Storage):
    bucket_name = 'my-media-bucket'
    custom_domain = '{}.s3.amazonaws.com'.format(bucket_name)

You can also decide to config your custom storage class to store files under a specific directory within the bucket:

class MediaStorage(S3Boto3Storage):
    bucket_name = 'my-app-bucket'
    location = 'media' # store files under directory `media/` in bucket `my-app-bucket`

This is especially useful when you want to have multiple storage classes share the same bucket:

class MediaStorage(S3Boto3Storage):
    bucket_name = 'my-app-bucket'
    location = 'media'

class StaticStorage(S3Boto3Storage):
    bucket_name = 'my-app-bucket'
    location = 'static'

So your bucket file can be organized like as below:

| my-app-bucket
| ├── media
| │   ├── user_video.mp4
| │   ├── user_file.pdf
| │   └── ...
| ├── static
| │   ├── app.js
| │   ├── app.css
| │   └── ...

Model

An object without a file has limited functionality:

from django.db import models
from django.core.files.base import ContentFile

class MyModel(models.Model):
  normal = models.FileField()

>>> obj1 = MyModel()
>>> obj1.normal
<FieldFile: None>
>>> obj1.normal.size
Traceback (most recent call last):
...
ValueError: The 'normal' attribute has no file associated with it.

Saving a file enables full functionality:

>>> obj1.normal.save('django_test.txt', ContentFile(b'content'))
>>> obj1.normal
<FieldFile: tests/django_test.txt>
>>> obj1.normal.size
7
>>> obj1.normal.read()
'content'

Files can be read in a little at a time, if necessary:

>>> obj1.normal.open()
>>> obj1.normal.read(3)
'con'
>>> obj1.normal.read()
'tent'
>>> '-'.join(obj1.normal.chunks(chunk_size=2))
'co-nt-en-t'

Save another file with the same name:

>>> obj2 = MyModel()
>>> obj2.normal.save('django_test.txt', ContentFile(b'more content'))
>>> obj2.normal
<FieldFile: tests/django_test.txt>
>>> obj2.normal.size
12

Push the objects into the cache to make sure they pickle properly:

>>> cache.set('obj1', obj1)
>>> cache.set('obj2', obj2)
>>> cache.get('obj2').normal
<FieldFile: tests/django_test.txt>

Clean up the temporary files:

>>> obj1.normal.delete()
>>> obj2.normal.delete()