Add DynamoDB session store (v2 session store gem) (#38)

Author: mullermp

.gitignore

@@ -5,6 +5,6 @@
 coverage
 doc
 Gemfile.lock
-test/dummy/log/
-test/dummy/tmp/
+spec/dummy/log/
+spec/dummy/tmp/
 vendor

README.md

@@ -1,9 +1,8 @@
 # AWS SDK for Ruby Rails Plugin
 
-[![Build
-Status](https://travis-ci.org/aws/aws-sdk-rails.png?branch=master)](https://travis-ci.org/aws/aws-sdk-rails)
-[![Code
-Climate](https://codeclimate.com/github/aws/aws-sdk-rails.png)](https://codeclimate.com/github/aws/aws-sdk-rails)
+[![Gem Version](https://badge.fury.io/rb/aws-sdk-rails.svg)](https://badge.fury.io/rb/aws-sdk-rails) [![Build Status](https://travis-ci.com/aws/aws-sdk-rails.svg?branch=master)](https://travis-ci.com/aws/aws-sdk-rails) [![Github forks](https://img.shields.io/github/forks/aws/aws-sdk-rails.svg)](https://github.com/aws/aws-sdk-rails/network)
+[![Github stars](https://img.shields.io/github/stars/aws/aws-sdk-rails.svg)](https://github.com/aws/aws-sdk-rails/stargazers)
+[![Gitter](https://badges.gitter.im/aws/aws-sdk-rails.svg)](https://gitter.im/aws/aws-sdk-rails?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
 
 A Ruby on Rails plugin that integrates AWS services with your application using
 the latest version of [AWS SDK For Ruby](https://github.com/aws/aws-sdk-ruby).
@@ -30,14 +29,14 @@ latest [AWS SDK for Ruby Docs](https://docs.aws.amazon.com/sdk-for-ruby/v3/api/i
 for details.
 
 If you're running your Rails application on Amazon EC2, the AWS SDK will
-automatically check Amazon EC2 instance metadata for credentials. Learn more:
+check Amazon EC2 instance metadata for credentials to load. Learn more:
 [IAM Roles for Amazon EC2](http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html)
 
 # Features
 
 ## AWS SDK uses the Rails logger
 
-The AWS SDK is automatically configured to use the built-in Rails logger for any
+The AWS SDK is configured to use the built-in Rails logger for any
 SDK log output. The logger is configured to use the `:info` log level. You can
 change the log level by setting `:log_level` in the
 [Aws.config](https://docs.aws.amazon.com/sdk-for-ruby/v3/api/Aws.html) hash.
@@ -48,10 +47,8 @@ Aws.config.update(log_level: :debug)
 
 ## Rails 5.2+ Encrypted Credentials
 
-If you are using Rails 5.2+ [Encrypted
-Credentials](http://guides.rubyonrails.org/security.html#custom-credentials),
-the credentials will be automatically loaded assuming the decrypted contents
-are provided as such:
+If you are using Rails 5.2+ [Encrypted Credentials](http://guides.rubyonrails.org/security.html#custom-credentials),
+the credentials will be decrypted and loaded under the `:aws` top level key:
 
 ```yml
 # config/credentials.yml.enc
@@ -61,6 +58,84 @@ aws:
   secret_access_key: YOUR_ACCESS_KEY
 ```
 
+## DynamoDB Session Store
+
+You can configure session storage in Rails to use DynamoDB instead of cookies,
+allowing access to sessions from other applications and devices. You will need
+to have an existing Amazon DynamoDB session table to use this feature.
+
+You can generate a migration file for the session table using the following
+command (<MigrationName> is optional):
+
+```bash
+rails generate dynamo_db:session_store_migration <MigrationName>
+```
+
+The session store migration generator command will generate two	files: a
+migration file, `db/migration/#{VERSION}_#{MIGRATION_NAME}.rb`, and a
+configuration YAML file, `config/dynamo_db_session_store.yml`.
+
+The migration file will create and delete a table with default options. These
+options can be changed prior to running the migration and are documented in the
+[Table](https://docs.aws.amazon.com/sdk-for-ruby/aws-sessionstore-dynamodb/api/Aws/SessionStore/DynamoDB/Table.html) class.
+
+To create the table, run migrations as normal with:
+
+```bash
+rake db:migrate
+```
+
+Next, configure the Rails session store to be `:dynamodb_store` by editing
+`config/initializers/session_store.rb` to contain the following:
+
+```ruby
+# config/initializers/session_store.rb
+Rails.application.config.session_store :dynamodb_store, key: '_your_app_session'
+```
+
+You can now start your Rails application with session support.
+
+### Configuration
+
+You can configure the session store with code, YAML files, or ENV, in this order
+of precedence. To configure in code, you can directly pass options to your
+initializer like so:
+
+```ruby
+# config/initializers/session_store.rb
+Rails.application.config.session_store :dynamodb_store,
+  key: '_your_app_session',
+  table_name: 'foo'
+```
+
+Alternatively, you can use the generated YAML configuration file
+`config/dynamo_db_session_store.yml`. YAML configuration may also be specified
+per environment, with environment configuration having precedence. To do this,
+create `config/dynamo_db_session_store/#{Rails.env}.yml` files as needed.
+
+For configuration options, see the [Configuration](https://docs.aws.amazon.com/sdk-for-ruby/aws-sessionstore-dynamodb/api/Aws/SessionStore/DynamoDB/Configuration.html) class.
+
+#### Rack Configuration
+
+DynamoDB session storage is implemented in the [`aws-sessionstore-dynamodb`](https://github.com/aws/aws-sessionstore-dynamodb-ruby)
+gem. The Rack middleware inherits from the [`Rack::Session::Abstract::Persisted`](https://www.rubydoc.info/github/rack/rack/Rack/Session/Abstract/Persisted)
+class, which also includes additional options (such as `:key`) that can be
+passed into the Rails initializer.
+
+### Cleaning old sessions
+
+By default sessions do not expire. See `config/dynamo_db_session_store.yml` to
+configure the max age or stale period of a session.
+
+You can use the DynamoDB [Time to Live (TTL) feature](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/TTL.html)
+on the `expire_at` attribute to automatically delete expired items.
+
+Alternatively, a Rake task for garbage collection is provided:
+
+```bash
+rake dynamo_db:collect_garbage
+```
+
 ## Amazon Simple Email Service (SES) as an ActionMailer Delivery Method
 
 This gem will automatically register SES as an ActionMailer delivery method. You
@@ -71,9 +146,7 @@ simply need to configure Rails to use it in your environment configuration:
 config.action_mailer.delivery_method = :ses
 ```
 
-# Other Usage
-
-## Manually setting Action Mailer credentials
+### Manually setting credentials
 
 If you need to provide different credentials for Action Mailer, you can call
 client-creating actions manually. For example, you can create an initializer
@@ -98,7 +171,7 @@ Aws::Rails.add_action_mailer_delivery_method(
 )
 ```
 
-## Using ARNs with SES
+### Using ARNs with SES
 
 This gem uses [`Aws::SES::Client#send_raw_email`](https://docs.aws.amazon.com/sdk-for-ruby/v3/api/Aws/SES/Client.html#send_raw_email-instance_method)
 to send emails. This operation allows you to specify a cross-account identity

aws-sdk-rails.gemspec

@@ -6,17 +6,19 @@ Gem::Specification.new do |spec|
   spec.name          = 'aws-sdk-rails'
   spec.version       = version
   spec.authors       = ['Amazon Web Services']
-  spec.email         = ['[email protected]', '[email protected]']
+  spec.email         = ['[email protected]', '[email protected]']
+
   spec.summary       = 'AWS SDK for Ruby on Rails Plugin'
   spec.description   = 'Integrates the AWS Ruby SDK with Ruby on Rails'
   spec.homepage      = 'https://github.com/aws/aws-sdk-rails'
   spec.license       = 'Apache-2.0'
 
   spec.require_paths = ['lib']
-  spec.files += Dir['lib/**/*.rb', 'lib/aws-sdk-rails.rb']
+  spec.files += Dir['lib/**/*.rb']
 
-  spec.add_dependency('aws-sdk-ses', '~> 1')
-  spec.add_dependency('railties', '>= 5.2.0')
+  spec.add_dependency('aws-sdk-ses', '~> 1') # for ActionMailer
+  spec.add_dependency('aws-sessionstore-dynamodb', '~> 2') # includes dynamo db
+  spec.add_dependency('railties', '>= 5.2.0') # encrypted credentials
 
   spec.add_development_dependency('rails')
 end

lib/action_dispatch/session/dynamodb_store.rb

@@ -0,0 +1,32 @@
+require 'aws-sessionstore-dynamodb'
+
+module ActionDispatch
+  module Session
+    # Uses the Dynamo DB Session Store implementation to create a class that
+    # extends ActionDispatch::Session. Rails will create a :dynamodb_store
+    # configuration for session_store from this class name.
+    #
+    # This class will use the Rails secret_key_base unless otherwise provided.
+    #
+    # Configuration can also be provided in YAML files from Rails config, either
+    # in "config/session_store.yml" or "config/session_store/#{Rails.env}.yml".
+    # Configuration files that are environment-specific will take precedence.
+    #
+    # @see https://docs.aws.amazon.com/sdk-for-ruby/aws-sessionstore-dynamodb/api/Aws/SessionStore/DynamoDB/Configuration.html
+    class DynamodbStore < Aws::SessionStore::DynamoDB::RackMiddleware
+      def initialize(app, options = {})
+        options[:config_file] ||= config_file if config_file.exist?
+        options[:secret_key] ||= Rails.application.secret_key_base
+        super
+      end
+
+      private
+
+      def config_file
+        file = Rails.root.join("config/dynamo_db_session_store/#{Rails.env}.yml")
+        file = Rails.root.join('config/dynamo_db_session_store.yml') unless file.exist?
+        file
+      end
+    end
+  end
+end

lib/aws-sdk-rails.rb

@@ -1,69 +1,7 @@
 # frozen_string_literal: true
 
 require_relative 'aws/rails/mailer'
-require_relative 'aws/rails/notifications_instrument_plugin'
+require_relative 'aws/rails/railtie'
+require_relative 'aws/rails/notifications_instrument'
 
-module Aws
-
-  # Use the Rails namespace.
-  module Rails
-
-    # @api private
-    class Railtie < ::Rails::Railtie
-      initializer 'aws-sdk-rails.initialize',
-                  before: :load_config_initializers do
-        # Initialization Actions
-        Aws::Rails.use_rails_encrypted_credentials
-        Aws::Rails.add_action_mailer_delivery_method
-        Aws::Rails.log_to_rails_logger
-      end
-    end
-
-    # This is called automatically from the SDK's Railtie, but can be manually
-    # called if you want to specify options for building the Aws::SES::Client.
-    #
-    # @param [Symbol] name The name of the ActionMailer delivery method to
-    #   register.
-    # @param [Hash] options The options you wish to pass on to the
-    #   Aws::SES::Client initialization method.
-    def self.add_action_mailer_delivery_method(name = :ses, options = {})
-      ActiveSupport.on_load(:action_mailer) do
-        add_delivery_method(name, Aws::Rails::Mailer, options)
-      end
-    end
-
-    # Configures the AWS SDK for Ruby's logger to use the Rails logger.
-    def self.log_to_rails_logger
-      Aws.config[:logger] = ::Rails.logger
-      nil
-    end
-
-    # Configures the AWS SDK with credentials from Rails encrypted credentials.
-    def self.use_rails_encrypted_credentials
-      # limit the config keys we merge to credentials only
-      aws_credential_keys = %i[access_key_id secret_access_key session_token]
-
-      Aws.config.merge!(
-        ::Rails.application
-          .try(:credentials)
-          .try(:aws)
-          .to_h.slice(*aws_credential_keys)
-      )
-    end
-
-    # Adds ActiveSupport Notifications instrumentation to AWS SDK
-    # client operations.  Each operation will produce an event with a name:
-    # <operation>.<service>.aws.  For example, S3's put_object has an event
-    # name of: put_object.S3.aws
-    def self.instrument_sdk_operations
-      Aws.constants.each do|c|
-        m = Aws.const_get(c)
-        if m.is_a?(Module) &&
-           m.const_defined?(:Client) &&
-           m.const_get(:Client).superclass == Seahorse::Client::Base
-          m.const_get(:Client).add_plugin(Aws::Rails::Notifications)
-        end
-      end
-    end
-  end
-end
+require_relative 'action_dispatch/session/dynamodb_store'

lib/aws/rails/notifications_instrument_plugin.rb renamed to lib/aws/rails/notifications_instrument.rb

@@ -0,0 +1,68 @@
+# frozen_string_literal: true
+
+module Aws
+  # Use the Rails namespace.
+  module Rails
+    # @api private
+    class Railtie < ::Rails::Railtie
+      initializer 'aws-sdk-rails.initialize',
+                  before: :load_config_initializers do
+        # Initialization Actions
+        Aws::Rails.use_rails_encrypted_credentials
+        Aws::Rails.add_action_mailer_delivery_method
+        Aws::Rails.log_to_rails_logger
+      end
+
+      rake_tasks do
+        load 'tasks/dynamo_db/session_store/clean.rake'
+      end
+    end
+
+    # This is called automatically from the SDK's Railtie, but can be manually
+    # called if you want to specify options for building the Aws::SES::Client.
+    #
+    # @param [Symbol] name The name of the ActionMailer delivery method to
+    #   register.
+    # @param [Hash] options The options you wish to pass on to the
+    #   Aws::SES::Client initialization method.
+    def self.add_action_mailer_delivery_method(name = :ses, options = {})
+      ActiveSupport.on_load(:action_mailer) do
+        add_delivery_method(name, Aws::Rails::Mailer, options)
+      end
+    end
+
+    # Configures the AWS SDK for Ruby's logger to use the Rails logger.
+    def self.log_to_rails_logger
+      Aws.config[:logger] = ::Rails.logger
+      nil
+    end
+
+    # Configures the AWS SDK with credentials from Rails encrypted credentials.
+    def self.use_rails_encrypted_credentials
+      # limit the config keys we merge to credentials only
+      aws_credential_keys = %i[access_key_id secret_access_key session_token]
+
+      Aws.config.merge!(
+        ::Rails.application
+          .try(:credentials)
+          .try(:aws)
+          .to_h.slice(*aws_credential_keys)
+      )
+    end
+
+    # Adds ActiveSupport Notifications instrumentation to AWS SDK
+    # client operations.  Each operation will produce an event with a name:
+    # <operation>.<service>.aws.  For example, S3's put_object has an event
+    # name of: put_object.S3.aws
+    def self.instrument_sdk_operations
+      Aws.constants.each do|c|
+        m = Aws.const_get(c)
+        if m.is_a?(Module) &&
+           m.const_defined?(:Client) &&
+           m.const_get(:Client).superclass == Seahorse::Client::Base
+          m.const_get(:Client).add_plugin(Aws::Rails::Notifications)
+        end
+      end
+    end
+  end
+end

lib/aws/rails/railtie.rb

@@ -0,0 +1,13 @@
+Description:
+    Generates a migration file for deleting and a creating a DynamoDB
+    sessions table, and a configuration file for the session store.
+
+Example:
+    rails generate dynamo_db:session_store_migration <MIGRATION_NAME>
+
+    This will create:
+        db/migrate/#{VERSION}_#{MIGRATION_NAME}.rb
+        config/dynamo_db_session_store.yml
+
+    The migration will be run when the command rake db:migrate is run
+    in the command line.