znbstatic

Custom Django storage backend.

Features

• Storage of assets managed by collectstatic on Amazon Web Services S3.
• Versioning using a variable from Django's settings (https://example.com/static/css/styles.css?v=1.2)

Installing and Uninstalling Packages

Installing in editable mode from local directory.

$ pip install -e /path/to/znbstatic/

You can remove the -e to install the package in the corresponding Python path, for example: /env/lib/python3.7/site-packages/znbstatic.

List installed packages and uninstall.

$ pip list
$ pip uninstall znbstatic

Installing from git using https.

$ pip install git+https://github.com/requests/requests.git#egg=requests
$ pip install git+https://github.com/alexisbellido/znbstatic.git#egg=znbstatic

This package could be added to a pip requirements.txt file from its git repository or source directory.

git+https://github.com/alexisbellido/znbstatic.git#egg=znbstatic
-e /path-to/znbstatic/

or from PyPi, in this case passing a specific version.

znbstatic==0.2

Znbstatic will require, and install if necessary, Django, boto3 and django-storages.

Updating Django Settings

Add the following to INSTALLED_APPS

'znbstatic.apps.ZnbStaticConfig'

Make sure these two are also installed.

'storages'
'django.contrib.staticfiles'

Add the znbstatic.context_processors.static_urls context processor to the correspoding template engine.

Update or insert the following attributes.

# if hosting the static files locally. # STATICFILES_STORAGE = 'znbstatic.storage.VersionedStaticFilesStorage' # STATIC_URL = '/static/'

# use the following if using Amazon S3 STATICFILES_STORAGE = 'znbstatic.storage.VersionedS3StaticFilesStorage'

AWS_ACCESS_KEY_ID = 'your-access-key-id' AWS_SECRET_ACCESS_KEY = 'your-secret-access-key'

AWS_STORAGE_STATIC_BUCKET_NAME = 'static.example.com'

# where is this used? AWS_S3_HOST = 's3.amazonaws.com'

S3_USE_SIGV4 = True AWS_QUERYSTRING_AUTH = False AWS_DEFAULT_ACL = 'public-read' STATIC_URL = 'https://s3.amazonaws.com/%s/' % AWS_STORAGE_STATIC_BUCKET_NAME

ZNBSTATIC_VERSION = '0.1'

Amazon S3

Some notes to use S3 for storing Django files.

Cross-origin resource sharing (CORS) defines a way for client web applications that are loaded in one domain to interact with resources in a different domain.

More on S3 access permissions.

Option 1 (preferred): Resource-based policy.

A bucket configured to be allow publc read access and full control by a IAM user that will be used from Django.

Create a IAM user. Write down the arn and user credentials (AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY).

Don't worry about adding a user policy as you will be using a bucket policy to refer to this user by its arn.

Create an S3 bucket at url-of-s3-bucket.

Assign it the following CORS configuration in the permissions tab.

<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
  <CORSRule>
      <AllowedOrigin>*</AllowedOrigin>
      <AllowedMethod>GET</AllowedMethod>
      <MaxAgeSeconds>3000</MaxAgeSeconds>
      <AllowedHeader>Authorization</AllowedHeader>
  </CORSRule>
</CORSConfiguration>

Go to permissions, public access settings for the bucket and set these options to false or you won't be able to use * as Principal in the bucket policy:

Block new public ACLs and uploading public objects (Recommended)
Remove public access granted through public ACLs (Recommended)
Block new public bucket policies (Recommended)
Block public and cross-account access if bucket has public policies (Recommended)

and the following bucket policy (use the corresponding arn for the bucket and for the IAM user that will have full control).

{
    "Version": "2012-10-17",
    "Id": "name-of-bucket",
    "Statement": [
        {
            "Sid": "PublicReadForGetBucketObjects",
            "Effect": "Allow",
            "Principal": "*",
            "Action": "s3:GetObject",
            "Resource": "arn:aws:s3:::name-of-bucket/*"
        },
        {
            "Sid": "FullControlForBucketObjects",
            "Effect": "Allow",
            "Principal": {
                "AWS": "arn:aws:iam::364908532015:user/name-of-user"
            },
            "Action": "s3:*",
            "Resource": [
                "arn:aws:s3:::name-of-bucket",
                "arn:aws:s3:::name-of-bucket/*"
            ]
        }
    ]
}

Option 2: user policy.

A user configured to control an specific bucket.

Create an S3 bucket at url-of-s3-bucket.

Assign it the following CORS configuration in the permissions tab.

<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
<CORSRule>
    <AllowedOrigin>*</AllowedOrigin>
    <AllowedMethod>GET</AllowedMethod>
    <MaxAgeSeconds>3000</MaxAgeSeconds>
    <AllowedHeader>Authorization</AllowedHeader>
</CORSRule>
</CORSConfiguration>

Create a user in IAM and assign it to this policy.

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Sid": "Stmt1394043345000",
            "Effect": "Allow",
            "Action": [
                "s3:*"
            ],
            "Resource": [
                "arn:aws:s3:::url-of-s3-bucket/*"
            ]
        }
    ]
}

Then create the user credentials (AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY) to connect from Django.