AWS SDK for Ruby Rails Plugin

A Ruby on Rails plugin that integrates AWS services with your application using the latest version of AWS SDK For Ruby.

Installation

Add this gem to your Rails project's Gemfile:

gem 'aws-sdk-rails'

This gem also brings in the following AWS gems:

• aws-sdk-ses
• aws-sdk-sesv2
• aws-sdk-sqs
• aws-record
• aws-sessionstore-dynamodb

If you want to use other services (such as S3), you will still need to add them to your Gemfile:

gem 'aws-sdk-rails', '~> 3'
gem 'aws-sdk-s3', '~> 1'

You will have to ensure that you provide credentials for the SDK to use. See the latest AWS SDK for Ruby Docs for details.

If you're running your Rails application on Amazon EC2, the AWS SDK will check Amazon EC2 instance metadata for credentials to load. Learn more: IAM Roles for Amazon EC2

Features

AWS SDK uses the Rails logger

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 hash.

Aws.config.update(log_level: :debug)

Rails 5.2+ Encrypted Credentials

If you are using Rails 5.2+ Encrypted Credentials, the credentials will be decrypted and loaded under the :aws top level key:

# config/credentials.yml.enc
# viewable with: `rails credentials:edit`
aws:
  access_key_id: YOUR_KEY_ID
  secret_access_key: YOUR_ACCESS_KEY

Encrypted Credentials will take precedence over any other AWS Credentials that may exist in your environment (eg: credentials from profiles set in ~/.aws/credentials).

If you are using ActiveStorage with S3 then you do not need to specify your credentials in your storage.yml configuration: they will be loaded automatically.

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 ( is optional):

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 class.

To create the table, run migrations as normal with:

rails db:migrate

Next, configure the Rails session store to be :dynamodb_store by editing config/initializers/session_store.rb to contain the following:

# 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:

# config/initializers/session_store.rb
Rails.application.config.session_store :dynamodb_store,
  key: '_your_app_session',
  table_name: 'foo',
  dynamo_db_client: my_ddb_client

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 class.

Rack Configuration

DynamoDB session storage is implemented in the `aws-sessionstore-dynamodb` gem. The Rack middleware inherits from the `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 on the expire_at attribute to automatically delete expired items.

Alternatively, a Rake task for garbage collection is provided:

rake dynamo_db:collect_garbage

Amazon Simple Email Service (SES) as an ActionMailer Delivery Method

This gem will automatically register SES and SESV2 as ActionMailer delivery methods. You simply need to configure Rails to use it in your environment configuration:

# for e.g.: config/environments/production.rb
config.action_mailer.delivery_method = :ses # or :sesv2

Override credentials or other client options

Client options can be overridden by re-registering the mailer with any set of SES or SESV2 Client options. You can create a Rails initializer config/initializers/aws.rb with contents similar to the following:

require 'json'

# Assuming a file "path/to/aws_secrets.json" with contents like:
#
#     { "AccessKeyId": "YOUR_KEY_ID", "SecretAccessKey": "YOUR_ACCESS_KEY" }
#
# Remember to exclude "path/to/aws_secrets.json" from version control, e.g. by
# adding it to .gitignore
secrets = JSON.load(File.read('path/to/aws_secrets.json'))
creds = Aws::Credentials.new(secrets['AccessKeyId'], secrets['SecretAccessKey'])

Aws::Rails.add_action_mailer_delivery_method(
  :ses, # or :sesv2
  credentials: creds,
  region: 'us-east-1',
  # some other config
)

Using ARNs with SES

This gem uses `Aws::SES::Client#send_raw_email` and `Aws::SESV2::Client#send_email` to send emails. This operation allows you to specify a cross-account identity for the email's Source, From, and Return-Path. To set these ARNs, use any of the following headers on your Mail::Message object returned by your Mailer class:

• X-SES-SOURCE-ARN

• X-SES-FROM-ARN

• X-SES-RETURN-PATH-ARN

Example:

# in your Rails controller
message = MyMailer.send_email(options)
message['X-SES-FROM-ARN'] = 'arn:aws:ses:us-west-2:012345678910:identity/[email protected]'
message.deliver

Active Support Notification Instrumentation for AWS SDK calls

To add ActiveSupport::Notifications Instrumentation to all AWS SDK client operations call Aws::Rails.instrument_sdk_operations before you construct any SDK clients.

Example usage in config/initializers/instrument_aws_sdk.rb

Aws::Rails.instrument_sdk_operations

Events are published for each client operation call with the following event name: ..aws. For example, S3's put_object has an event name of: put_object.S3.aws. The service name will always match the namespace of the service client (eg Aws::S3::Client => 'S3'). The payload of the event is the request context.

You can subscribe to these events as you would other ActiveSupport::Notifications:

ActiveSupport::Notifications.subscribe('put_object.S3.aws') do |name, start, finish, id, payload|
 # process event
end

# Or use a regex to subscribe to all service notifications
ActiveSupport::Notifications.subscribe(/S3[.]aws/) do |name, start, finish, id, payload|
 # process event
end

AWS SQS Active Job

This package provides a lightweight, high performance SQS backend for ActiveJob.

To use AWS SQS ActiveJob as your queuing backend, simply set the active_job.queue_adapter to :amazon or :amazon_sqs (note, :amazon has been used for a number of other Amazon rails adapters such as ActiveStorage, so has been carried forward as convention here). For details on setting the queuing backend see: ActiveJob: Setting the Backend. To use the non-blocking (async) adapter set active_job.queue_adapter to :amazon_sqs_async. If you have a lot of jobs to queue or you need to avoid the extra latency from an SQS call in your request then consider using the async adapter. However, you may also want to configure a async_queue_error_handler to handle errors that may occur when queuing jobs. See the Aws::Rails::SqsActiveJob::Configuration for documentation.

# config/application.rb
module YourApp
  class Application < Rails::Application
    config.active_job.queue_adapter = :amazon_sqs # note: can use either :amazon or :amazon_sqs
    # To use the non-blocking async adapter:
    # config.active_job.queue_adapter = :amazon_sqs_async
  end
end

# Or to set the adapter for a single job:
class YourJob < ApplicationJob
  self.queue_adapter = :amazon_sqs
  #....
end

You also need to configure a mapping of ActiveJob queue name to SQS Queue URL. For more details, see the configuration section below.

# config/aws_sqs_active_job.yml
queues:
  default: 'https://my-queue-url.amazon.aws'

To queue a job, you can just use standard ActiveJob methods:

# To queue for immediate processing
YourJob.perform_later(args)

# or to schedule a job for a future time:
YourJob.set(wait: 1.minute).perform_later(args)

Note: Due to limitations in SQS, you cannot schedule jobs for later than 15 minutes in the future.

Retry Behavior and Handling Errors

See the Rails ActiveJob Guide on Exceptions for background on how ActiveJob handles exceptions and retries.

In general - you should configure retries for your jobs using retry_on. When configured, ActiveJob will catch the exception and reschedule the job for re-execution after the configured delay. This will delete the original message from the SQS queue and requeue a new message.

By default SQS ActiveJob is configured with retry_standard_error set to true and will not delete messages for jobs that raise a StandardError and that do not handle that error via retry_on or discard_on. These job messages will remain on the queue and will be re-read and retried following the SQS Queue's configured retry and DLQ settings. If you do not have a DLQ configured, the message will continue to be attempted until it reaches the queues retention period. In general, it is a best practice to configure a DLQ to store unprocessable jobs for troubleshooting and redrive.

If you want failed jobs that do not have retry_on or discard_on configured to be immediately discarded and not left on the queue, set retry_standard_error to false. See the configuration section below for details.

Running workers - polling for jobs

To start processing jobs, you need to start a separate process (in additional to your Rails app) with bin/aws_sqs_active_job (an executable script provided with this gem). You need to specify the queue to process jobs from:

RAILS_ENV=development bundle exec aws_sqs_active_job --queue default

To see a complete list of arguments use --help.

You can kill the process at any time with CTRL+C - the processor will attempt to shutdown cleanly and will wait up to :shutdown_timeout seconds for all actively running jobs to finish before killing them.

Note: When running in production, its recommended that use a process supervisor such as foreman, systemd, upstart, daemontools, launchd, runit, ect.

Performance

AWS SQS ActiveJob is a lightweight and performant queueing backend. Benchmark performed using: Ruby MRI 2.6.5,
shoryuken 5.0.5, aws-sdk-rails 3.3.1 and aws-sdk-sqs 1.34.0 on a 2015 Macbook Pro dual-core i7 with 16GB ram.

AWS SQS ActiveJob (default settings): Throughput 119.1 jobs/sec Shoryuken (default settings): Throughput 76.8 jobs/sec

Serverless workers: processing activejobs using AWS Lambda

Rather than managing the worker processes yourself, you can use Lambda with an SQS Trigger. With Lambda Container Image Support and the lambda handler provided with aws-sdk-rails its easy to use lambda to run ActiveJobs for your dockerized rails app (see below for some tips). All you need to do is:

1. include the aws_lambda_ric gem
2. Push your image to ecr
3. Create a lambda function from your image (see the lambda docs for details).
4. Add an SQS Trigger for the queue(s) you want to process jobs from.
5. Set the ENTRYPOINT to /usr/local/bundle/bin/aws_lambda_ric and the CMD to config/environment.Aws::Rails::SqsActiveJob.lambda_job_handler - this will load Rails and then use the lambda handler provided by aws-sdk-rails. You can do this either as function config or in your Dockerfile.

There are a few limitations/requirements for lambda container images: the default lambda user must be able to read all the files and the image must be able to run on a read only file system. You may need to disable bootsnap, set a HOME env variable and set the logger to STDOUT (which lambda will record to cloudwatch for you).

You can use the RAILS_ENV to control environment. If you need to execute specific configuration in the lambda, you can create a ruby file and use it as your entrypoint:

# app.rb
# some custom config

require_relative 'config/environment' # load rails

# Rails.config.custom....
# Aws::Rails::SqsActiveJob.config....

# no need to write a handler yourself here, as long as
# aws-sdk-rails is loaded, you can still use the
# Aws::Rails::SqsActiveJob.lambda_job_handler

# To use this file, set CMD:  app.Aws::Rails::SqsActiveJob.lambda_job_handler

Elastic Beanstalk workers: processing activejobs using worker environments

Another option for processing jobs without managing the worker process is hosting the application in a scalable Elastic Beanstalk worker environment. This SDK includes Rack middleware that can be added conditionally and which will process requests from the SQS Daemon provided with each worker instance. The middleware will forward each request and parameters to their appropriate jobs.

To add the middleware on application startup, set the AWS_PROCESS_BEANSTALK_WORKER_REQUESTS environment variable to true in the worker environment configuration.

To protect against forgeries, daemon requests will only be processed if they originate from localhost or the Docker host.

Periodic (scheduled) jobs are also supported with this approach without requiring any additional dependencies. Elastic Beanstalk workers support the addition of a cron.yaml file in the application root to configure this.

Example:

version: 1
cron:
 - name: "MyApplicationJob"
   url: "/"
   schedule: "0 */12 * * *"

Where 'name' must be the case-sensitive class name of the job.

Configuration

For a complete list of configuration options see the Aws::Rails::SqsActiveJob::Configuration documentation.

You can configure AWS SQS Active Job either through the yml file or through code in your config/.rb or initializers.

For file based configuration, you can use either:

1. config/aws_sqs_active_job/<RAILS_ENV>.yml
2. config/aws_sqs_active_job.yml

The yml file supports ERB.

To configure in code:

Aws::Rails::SqsActiveJob.configure do |config|
  config.logger = ActiveSupport::Logger.new(STDOUT)
  config.max_messages = 5
  config.client = Aws::SQS::Client.new(region: 'us-east-1')
end

Using FIFO queues

If the order in which your jobs executes is important, consider using a FIFO Queue. A FIFO queue ensures that messages are processed in the order they were sent (First-In-First-Out) and exactly-once processing (ensuring duplicates are never introduced into the queue). To use a fifo queue, simply set the queue url (which will end in ".fifo") in your config.

When using FIFO queues, jobs will NOT be processed concurrently by the poller to ensure the correct ordering. Additionally, all jobs on a FIFO queue will be queued synchronously, even if you have configured the amazon_sqs_async adapter.

Message Deduplication ID

FIFO queues support Message deduplication ID, which is the token used for deduplication of sent messages. If a message with a particular message deduplication ID is sent successfully, any messages sent with the same message deduplication ID are accepted successfully but aren't delivered during the 5-minute deduplication interval.

Customize Deduplication keys

If necessary, the deduplication key used to create the message deduplication ID can be customized:

Aws::Rails::SqsActiveJob.configure do |config|
  config.excluded_deduplication_keys = [:job_class, :arguments]
end

# Or to set deduplication keys to exclude for a single job:
class YourJob < ApplicationJob
  include Aws::Rails::SqsActiveJob
  deduplicate_without :job_class, :arguments
  #...
end

By default, the following keys are used for deduplication keys:

job_class, provider_job_id, queue_name, priority, arguments, executions, exception_executions, locale, timezone, enqueued_at

Note that job_id is NOT included in deduplication keys because it is unique for each initialization of the job, and the run-once behavior must be guaranteed for ActiveJob retries. Even without setting job_id, it is implicitly excluded from deduplication keys.

Message Group IDs

FIFO queues require a message group id to be provided for the job. It is determined by:

1. Calling message_group_id on the job if it is defined
2. If message_group_id is not defined or the result is nil, the default value will be used. You can optionally specify a custom value in your config as the default that will be used by all jobs.

AWS Record Generators

This package also pulls in the `aws-record` gem and provides generators for creating models and a rake task for performing table config migrations.

Setup

You can either invoke the generator by calling rails g aws_record:model ...

If DynamoDB will be the only datastore you plan on using you can also set aws-record-generator to be your project's default orm with

config.generators do |g|
  g.orm :aws_record
end

Which will cause aws_record:model to be invoked by the Rails model generator.

Generating a model

Generating a model can be as simple as: rails g aws_record:model Forum --table-config primary:10-5 aws-record-generator will automatically create a uuid:hash_key field for you, and a table config with the provided r/w units

# app/models/forum.rb

require 'aws-record'

class Forum
  include Aws::Record

  string_attr :uuid, hash_key: true
end

# db/table_config/forum_config.rb

require 'aws-record'

module ModelTableConfig
  def self.config
    Aws::Record::TableConfig.define do |t|
      t.model_class Forum

      t.read_capacity_units 10
      t.write_capacity_units 5
    end
  end
end

More complex models can be created by adding more fields to the model as well as other options:

rails g aws_record Forum post_id:rkey author_username post_title post_body tags:sset:default_value{Set.new}

# app/models/forum.rb

require 'aws-record'

class Forum
  include Aws::Record

  string_attr :uuid, hash_key: true
  string_attr :post_id, range_key: true
  string_attr :author_username
  string_attr :post_title
  string_attr :post_body
  string_set_attr :tags, default_value: Set.new
end

# db/table_config/forum_config.rb
# ...

Finally you can attach a variety of options to your fields, and even ActiveModel validations to the models:

rails g aws_record:model Forum forum_uuid:hkey post_id:rkey author_username post_title post_body tags:sset:default_value{Set.new} created_at:datetime:db_attr_name{PostCreatedAtTime} moderation:boolean:default_value{false} --table-config=primary:5-2 AuthorIndex:12-14 --required=post_title --length-validations=post_body:50-1000 --gsi=AuthorIndex:hkey{author_username}

Which results in the following files being generated:

# app/models/forum.rb

require 'aws-record'
require 'active_model'

class Forum
  include Aws::Record
  include ActiveModel::Validations

  string_attr :forum_uuid, hash_key: true
  string_attr :post_id, range_key: true
  string_attr :author_username
  string_attr :post_title
  string_attr :post_body
  string_set_attr :tags, default_value: Set.new
  datetime_attr :created_at, database_attribute_name: "PostCreatedAtTime"
  boolean_attr :moderation, default_value: false

  global_secondary_index(
    :AuthorIndex,
    hash_key: :author_username,
    projection: {
      projection_type: "ALL"
    }
  )
  validates_presence_of :post_title
  validates_length_of :post_body, within: 50..1000
end

# db/table_config/forum_config.rb
# ...

To migrate your new models and begin using them you can run the provided rake task: rails aws_record:migrate

Docs

The syntax for creating an aws-record model follows:

rails generate aws_record:model NAME [field[:type][:opts]...] [options]

The possible field types are:

Field Name	aws-record attribute type
bool | boolean	:boolean_attr
date	:date_attr
datetime	:datetime_attr
float	:float_attr
int | integer	:integer_attr
list	:list_attr
map	:map_attr
num_set | numeric_set | nset	:numeric_set_attr
string_set | s_set | sset	:string_set_attr
string	:string_attr

If a type is not provided, it will assume the field is of type :string_attr.

Additionally a number of options may be attached as a comma separated list to the field:

Field Option Name	aws-record option
hkey	marks an attribute as a hash_key
rkey	marks an attribute as a range_key
persist_nil	will persist nil values in a attribute
db_attr_name{NAME}	sets a secondary name for an attribute, these must be unique across attribute names
ddb_type{S|N|B|BOOL|SS|NS|BS|M|L}	sets the dynamo_db_type for an attribute
default_value{Object}	sets the default value for an attribute

The standard rules apply for using options in a model. Additional reading can be found here

Command Option Names	Purpose
[--skip-namespace], [--no-skip-namespace]	Skip namespace (affects only isolated applications)
[--disable-mutation-tracking], [--no-disable-mutation-tracking]	Disables dirty tracking
[--timestamps], [--no-timestamps]	Adds created, updated timestamps to the model
--table-config=primary:R-W [SecondaryIndex1:R-W]...	Declares the r/w units for the model as well as any secondary indexes
[--gsi=name:hkey{ field_name }[,rkey{ field_name },proj_type{ ALL|KEYS_ONLY|INCLUDE }]...]	Allows for the declaration of secondary indexes
[--required=field1...]	A list of attributes that are required for an instance of the model
[--length-validations=field1:MIN-MAX...]	Validations on the length of attributes in a model
[--table-name=name]	Sets the name of the table in DynamoDB, if different than the model name
[--skip-table-config]	Doesn't generate a table config for the model
[--password-digest]	Adds a password field (note that you must have bcrypt has a dependency) that automatically hashes and manages the model password

The included rake task aws_record:migrate will run all of the migrations in app/db/table_config