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Performance Tuning / Remote Filesystems / Amazon S3

Configuring Bolt to use Amazon Simple Storage Service (Amazon S3) requires the addition of Flysystem and caching libraries, as well as custom service provider code to your project.

  1. Set-up, configure, and confirm operational your Amazon S3 bucket
  2. Update composer.json in your project root
  3. Creating service providers
  4. Bootstrap your providers


Warning: This documentation, and examples, assume you have a fully configured and working Amazon S3 bucket.

Required Libraries

You need to add the following libraries to your project:

  • league/flysystem-aws-s3-v3:^1.0
  • league/flysystem-cached-adapter:^1.0

This can simply be achieved by running:

$ composer require league/flysystem-aws-s3-v3:^1.0 league/flysystem-cached-adapter:^1.0

Caching Libraries

While other cache targets are optional, right now this example will be based on Redis. Alternatively any PSR-6 can be used, as well as Doctrine Cache.

To use Redis, you will need a configured and running Redis instance, and need to install predis/predis:^1.1, which can be achieved by running:

$ composer require predis/predis:^1.1

The cache needs to be shared between servers caching for the same site, else cache results will be inconsistent, unreliable, and self-defeating of the aim of caching.

We recommend using Amazon ElastiCache for a shared Redis instance, and using the Predis library to connect to it.


Autoloading of your service providers can be set-up in the same way as Extension Bundles, by adding your base namespace and source directory ot the psr-4 section of your project root composer.json file, e.g.

    "autoload": {
        "psr-4": {
            "MySiteApp\\": "src"

Note: If you change anything in the psr-4 section of your composer.json file, remember to re-run composer dump-autoload to update the cached autoloading files.

Service Providers

Amazon AWS

The provider for Amazon AWS services needs to define app['aws.s3'], that returns an \Aws\S3\S3Client used to interact with Amazon Simple Storage Service (Amazon S3).

For detailed information on constructing these classes, and the options provided see the Amazon S3 documentation, and specifically the S3 SDK documentation and S3 ApiGen documentation.

Amazon Credentials

This credential provider first checks in order:

  • Amazon AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables
  • "default" profile in ~/.aws/credentials, or the profile specified by the AWS_PROFILE environment variable
  • "profile default" profile in ~/.aws/config (which is the default profile of AWS CLI)
  • Fetch credentials from the ECS environment variables
  • Fetches credentials for the EC2 instance's IAM Role
    • If you are using EC2 instances then this is the recommended way to provide credentials

For information on the Aws\Credentials classes, see Amazon's ApiGen documentation for AWS Credentials.

If using an IAM policy, you'll need to attach the follwoing to the IAM user role:

    "Version": "2012-10-17",
    "Statement": [
            "Effect": "Allow",
            "Action": [
            "Resource": "arn:aws:s3:::bucket-name/*"


Filesystem Cache Factory

Create a protected callable $app['filesystem.cache_factory'] that when invoked returns an instance of \Bolt\Filesystem\Adapter\Cached.

S3 Filesystem Service

Create a protected callable $app['filesystem.s3'] that when invoked will return an a class implementing Bolt\Filesystem\FilesystemInterface.

If using \Bolt\Filesystem\Filesystem as your FilesystemInterface object, you first need to construct an \Bolt\Filesystem\Adapter\S3 adapter class.

Your adapter can then be passed to the $app['filesystem.cache_factory'] callable, and the return value used as the adpater parameter to construct Filesystem.

Extend Filesystem

Next, you must extend $app['filesystem'], and call mountFilesystems() using an associative array of the filesystem(s) you want to override using the S3 filesystem callable you define.


In order for functionality, like Twig's {{ asset() }} function to know about the variation in location of assets that is return to the requesting client, you need to next override the desired package in the package group with a Symfony\Component\Asset\UrlPackage object that defines your base Amazon S3 bucket URL.

This is achived by extending $app['asset.packages'], and adding your specific UrlPackage object to he desired package pool name.

Example Provider

This is an example of the src/Provider/AwsServiceProvider.php file.


namespace MySiteApp\Provider;

use Aws\Credentials\CredentialProvider;
use Aws\Credentials\Credentials;
use Aws\S3\S3Client;
use Bolt\Filesystem\Adapter;
use Bolt\Filesystem\Adapter\Cached;
use Bolt\Filesystem\Cached\DoctrineCache;
use Bolt\Filesystem\Filesystem;
use Doctrine\Common\Cache\PredisCache;
use Predis;
use Silex\Application;
use Silex\ServiceProviderInterface;
use Symfony\Component\Asset\UrlPackage;

class AwsServiceProvider implements ServiceProviderInterface
     * {@inheritdoc}
    public function register(Application $app)
         * Amazon S3 provider.
        $app['aws.s3'] = $app->share(function ($app) {
            return new S3Client([
                // The bucket's region name, e.g. 'eu-central-1'
                'region' => 'my-bucket-location',
                'version' => '2006-03-01',

         * Filesystem.
        $app['filesystem'] = $app->share($app->extend(
            function ($filesystem, $app) {
                $bucketName = 'your S3 bucket name';
                $prefix = '';

                $filesystems = [
                    'files' => $app['filesystem.s3']('files', $bucketName, $prefix)

                return $filesystem;
        // The S3 filesystem protected callable.
        $app['filesystem.s3'] = $app->protect(
            function ($name, $bucket, $prefix = '') use ($app) {
                $adapter = new Adapter\S3($app['aws.s3'], $bucket, $prefix);
                $adapter = $app['filesystem.cache_factory']($adapter, 'flysystem-' . $name, 3600);

                return new Filesystem($adapter);
        // Cache factory
        $app['filesystem.cache_factory'] = $app->protect(
            function ($adapter, $name, $expire = null) {
                // Note: Predis is use here as an example
                $cache = new DoctrineCache(new PredisCache(new Predis\Client()));

                return new Cached($adapter, $cache, $name, $expire);

         * Assets.
        $app['asset.packages'] = $app->share($app->extend(
            function ($packages, $app) {
                $package = new UrlPackage(
                    // CloudFront CDN url can also be used here
                $packages->addPackage('files', $package);

                return $packages;

     * {@inheritdoc}
    public function boot(Application $app)

A note on the parameters passed to UrlPackage:

  • First parameter for UrlPackage is the base URL or your Amazon S3 bucket
  • Second parameter is the version strategy applicable to the package
  • Third parameter is the must be the name of the package you're replacing, and must be the mount point of the filesystem you are changing. This also applies to the first parameter used in addPackage() as well.

In this example, 'files' is package name, that is package that is responsible for the contents of your project's files/ mount point.

Optionally, you may with to construct your own \Aws\Credentials\Credentials object, and pass that to CredentialProvider::fromCredentials(), e.g.

    $app['aws.s3'] = $app->share(function ($app) {
        $accessKey = 'your access key from Amazon';
        $secretKey = 'your secret key from Amazon';
        $credentials = CredentialProvider::fromCredentials(new Credentials($accessKey, $secretKey));
        return new S3Client([
            // The bucket's region name, e.g. 'eu-central-1'
            'region' => 'my-bucket-location',
            'version' => '2006-03-01',
            'credentials' => $credentials,

Bootstrap Configuration

Finally, to load your services, add them to your services: key in the site's .bolt.yml or .bolt.php files.

Example using .bolt.yml:

  - MySiteApp\Provider\FilesystemServiceProvider
  - MySiteApp\Provider\AwsServiceProvider
  - MySiteApp\Provider\AssetServiceProvider

Example using .bolt.php instead:

return [
    'services' => [
        new MySiteApp\Provider\FilesystemServiceProvider(),
        new MySiteApp\Provider\AwsServiceProvider(),
        new MySiteApp\Provider\AssetServiceProvider(),
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