watsonso/good_job

Multithreaded, Postgres-based, ActiveJob backend for Ruby on Rails.

GoodJob

GoodJob is a multithreaded, Postgres-based, ActiveJob backend for Ruby on Rails.

Inspired by Delayed::Job and Que, GoodJob is designed for maximum compatibility with Ruby on Rails, ActiveJob, and Postgres to be simple and performant for most workloads.

• Designed for ActiveJob. Complete support for async, queues, delays, priorities, timeouts, and retries with near-zero configuration.
• Built for Rails. Fully adopts Ruby on Rails threading and code execution guidelines with Concurrent::Ruby.
• Backed by Postgres. Relies upon Postgres integrity, session-level Advisory Locks to provide run-once safety and stay within the limits of schema.rb, and LISTEN/NOTIFY to reduce queuing latency.
• For most workloads. Targets full-stack teams, economy-minded solo developers, and applications that enqueue less than 1-million jobs/day.

For more of the story of GoodJob, read the introductory blog post.

📊 Comparison of GoodJob with other job queue backends (click to expand)

	Queues, priority, retries	Database	Concurrency	Reliability/Integrity	Latency
GoodJob	✅ Yes	✅ Postgres	✅ Multithreaded	✅ ACID, Advisory Locks	✅ Postgres LISTEN/NOTIFY
Que	✅ Yes	🔶️ Postgres, requires structure.sql	✅ Multithreaded	✅ ACID, Advisory Locks	✅ Postgres LISTEN/NOTIFY
Delayed Job	✅ Yes	✅ Postgres	🔴 Single-threaded	✅ ACID, record-based	🔶 Polling
Sidekiq	✅ Yes	🔴 Redis	✅ Multithreaded	🔴 Crashes lose jobs	✅ Redis BRPOP
Sidekiq Pro	✅ Yes	🔴 Redis	✅ Multithreaded	✅ Redis RPOPLPUSH	✅ Redis RPOPLPUSH

Table of contents

• Set up
• Configuration
  • Command-line options
    • good_job start
    • good_job cleanup_preserved_jobs
  • Adapter options
  • Global options
  • Dashboard
• Go deeper
  • Exceptions, retries, and reliability
    • Exceptions
    • Retries
    • ActionMailer retries
  • Timeouts
  • Optimize queues, threads, and processes
  • Database connections
  • Execute jobs async / in-process
  • Migrate to GoodJob from a different ActiveJob backend
  • Monitor and preserve worked jobs
• Contribute
  • Gem development
  • Release
• License

Set up

1. Add good_job to your application's Gemfile:

   gem 'good_job'

2. Install the gem:

   $ bundle install

3. Run the GoodJob install generator. This will generate a database migration to create a table for GoodJob's job records:

   $ bin/rails g good_job:install

   Run the migration:

   $ bin/rails db:migrate

4. Configure the ActiveJob adapter:

   # config/application.rb
   config.active_job.queue_adapter = :good_job

5. Inside of your application, queue your job 🎉:

   YourJob.perform_later

   GoodJob supports all ActiveJob features:

   YourJob.set(queue: :some_queue, wait: 5.minutes, priority: 10).perform_later

6. In development, GoodJob executes jobs immediately. In production, GoodJob provides different options:

   • By default, GoodJob separates job enqueuing from job execution so that jobs can be scaled independently of the web server. Use the GoodJob command-line tool to execute jobs:

     $ bundle exec good_job start

     Ideally the command-line tool should be run on a separate machine or container from the web process. For example, on Heroku:

     web: rails server
     worker: bundle exec good_job start

     The command-line tool supports a variety of options, see the reference below for command-line configuration.

   • GoodJob can also be configured to execute jobs within the web server process to save on resources. This is useful for low-workloads when economy is paramount.

     $ GOOD_JOB_EXECUTION_MODE=async rails server
     

     Additional configuration is likely necessary, see the reference below for async configuration.

Configuration

Command-line options

There several top-level commands available through the good_job command-line tool.

Configuration options are available with help.

good_job start

good_job start executes queued jobs.

$ bundle exec good_job help start

Usage:
  good_job start

Options:
  [--max-threads=COUNT]      # Maximum number of threads to use for working jobs. (env var: GOOD_JOB_MAX_THREADS, default: 5)
  [--queues=QUEUE_LIST]      # Queues to work from. (env var: GOOD_JOB_QUEUES, default: *)
  [--poll-interval=SECONDS]  # Interval between polls for available jobs in seconds (env var: GOOD_JOB_POLL_INTERVAL, default: 1)

Executes queued jobs.

All options can be configured with environment variables.
See option descriptions for the matching environment variable name.

== Configuring queues
Separate multiple queues with commas; exclude queues with a leading minus;
separate isolated execution pools with semicolons and threads with colons.

good_job cleanup_preserved_jobs

good_job cleanup_preserved_jobs deletes preserved job records. See [GoodJob.preserve_job_records for when this command is useful.

$ bundle exec good_job help cleanup_preserved_jobs

Usage:
  good_job cleanup_preserved_jobs

Options:
  [--before-seconds-ago=SECONDS] # Delete records finished more than this many seconds ago (env var:  GOOD_JOB_CLEANUP_PRESERVED_JOBS_BEFORE_SECONDS_AGO, default: 86400)

Deletes preserved job records.

By default, GoodJob deletes job records when the job is performed and this
command is not necessary.

However, when `GoodJob.preserve_job_records = true`, the jobs will be
preserved in the database. This is useful when wanting to analyze or
inspect job performance.

If you are preserving job records this way, use this command regularly
to delete old records and preserve space in your database.

Adapter options

To use GoodJob, you can set config.active_job.queue_adapter to a :good_job or to an instance of GoodJob::Adapter, which you can configure with several options:

• execution_mode (symbol) specifies how and where jobs should be executed. You can also set this with the environment variable GOOD_JOB_EXECUTION_MODE. It can be any one of:
  • :inline executes jobs immediately in whatever process queued them (usually the web server process). This should only be used in test and development environments.
  • :external causes the adapter to enqueue jobs, but not execute them. When using this option (the default for production environments), you’ll need to use the command-line tool to actually execute your jobs.
  • :async causes the adapter to execute you jobs in separate threads in whatever process queued them (usually the web process). This is akin to running the command-line tool’s code inside your web server. It can be more economical for small workloads (you don’t need a separate machine or environment for running your jobs), but if your web server is under heavy load or your jobs require a lot of resources, you should choose :external instead.
• max_threads (integer) sets the maximum number of threads to use when execution_mode is set to :async. You can also set this with the environment variable GOOD_JOB_MAX_THREADS.
• queues (string) determines which queues to execute jobs from when execution_mode is set to :async. See the description of good_job start for more details on the format of this string. You can also set this with the environment variable GOOD_JOB_QUEUES.
• poll_interval (integer) sets the number of seconds between polls for jobs when execution_mode is set to :async. You can also set this with the environment variable GOOD_JOB_POLL_INTERVAL.

Using the symbol instead of explicitly configuring the options above (i.e. setting config.active_job.queue_adapter = :good_job) is equivalent to:

# config/environments/development.rb
config.active_job.queue_adapter = GoodJob::Adapter.new(execution_mode: :inline)

# config/environments/test.rb
config.active_job.queue_adapter = GoodJob::Adapter.new(execution_mode: :inline)

# config/environments/production.rb
config.active_job.queue_adapter = GoodJob::Adapter.new(execution_mode: :external)

Global options

Good Job’s general behavior can also be configured via several attributes directly on the GoodJob module:

• GoodJob.logger (Rails Logger) lets you set a custom logger for GoodJob. It should be an instance of a Rails Logger.
• GoodJob.preserve_job_records (boolean) keeps job records in your database even after jobs are completed. (Default: false)
• GoodJob.retry_on_unhandled_error (boolean) causes jobs to be re-queued and retried if they raise an instance of StandardError. Instances of Exception, like SIGINT, will always be retried, regardless of this attribute’s value. (Default: true)
• GoodJob.on_thread_error (proc, lambda, or callable) will be called when an Exception. It can be useful for logging errors to bug tracking services, like Sentry or Airbrake.

You’ll generally want to configure these in config/initializers/good_job.rb, like so:

# config/initializers/good_job.rb
GoodJob.preserve_job_records = true
GoodJob.retry_on_unhandled_error = false
GoodJob.on_thread_error = -> (exception) { Raven.capture_exception(exception) }

Dashboard

🚧 GoodJob's dashboard is a work in progress. Please contribute ideas and code on Github.

GoodJob includes a Dashboard as a mountable Rails::Engine.

1. Explicitly require the Engine code at the top of your config/application.rb file, immediately after Rails is required. This is necessary because the mountable engine is an optional feature of GoodJob.

   # config/application.rb
   require_relative 'boot'
   
   require 'rails/all'
   require 'good_job/engine' # <= Add this line
   # ...

2. Mount the engine in your config/routes.rb file. The following will mount it at http://example.com/good_job.

   # config/routes.rb
   # ...
   mount GoodJob::Engine => 'good_job'

   Because jobs can potentially contain sensitive information, you should authorize access. For example, using Devise's authenticate helper, that might look like:

   # config/routes.rb
   # ...
   authenticate :user, ->(user) { user.admin? } do
     mount GoodJob::Engine => 'good_job'
   end

   Another option is using basic auth like this:

   # config/initializers/good_job.rb
   GoodJob::Engine.middleware.use(Rack::Auth::Basic) do |username, password|
     ActiveSupport::SecurityUtils.secure_compare(Rails.application.credentials.good_job_username, username) &&
       ActiveSupport::SecurityUtils.secure_compare(Rails.application.credentials.good_job_password, password)
   end

Go deeper

Exceptions, retries, and reliability

GoodJob guarantees that a completely-performed job will run once and only once. GoodJob fully supports ActiveJob's built-in functionality for error handling, retries and timeouts.

Exceptions

ActiveJob provides tools for rescuing and retrying exceptions, including retry_on, discard_on, rescue_from that will rescue exceptions before they get to GoodJob.

If errors do reach GoodJob, you can assign a callable to GoodJob.on_thread_error to be notified. For example, to log errors to an exception monitoring service like Sentry (or Bugsnag, Airbrake, Honeybadger, etc.):

# config/initializers/good_job.rb
GoodJob.on_thread_error = -> (exception) { Raven.capture_exception(exception) }

Retries

By default, GoodJob will automatically and immediately retry a job when an exception is raised to GoodJob.

However, ActiveJob can be configured to retry an infinite number of times, with an exponential backoff. Using ActiveJob's retry_on prevents exceptions from reaching GoodJob:

class ApplicationJob < ActiveJob::Base
  retry_on StandardError, wait: :exponentially_longer, attempts: Float::INFINITY
  # ...
end

When using retry_on with a limited number of retries, the final exception will not be rescued and will raise to GoodJob. GoodJob can be configured to discard un-handled exceptions instead of retrying them:

# config/initializers/good_job.rb
GoodJob.retry_on_unhandled_error = false

Alternatively, pass a block to retry_on to handle the final exception instead of raising it to GoodJob:

class ApplicationJob < ActiveJob::Base
  retry_on StandardError, attempts: 5 do |_job, _exception|
    # Log error, do nothing, etc.
  end
  # ...
end

When using retry_on with an infinite number of retries, exceptions will never be raised to GoodJob, which means GoodJob.on_thread_error will never be called. To report log or report exceptions to an exception monitoring service (e.g. Sentry, Bugsnag, Airbrake, Honeybadger, etc), create an explicit exception wrapper. For example:

class ApplicationJob < ActiveJob::Base
  retry_on StandardError, wait: :exponentially_longer, attempts: Float::INFINITY

  retry_on SpecialError, attempts: 5 do |_job, exception|
    Raven.capture_exception(exception)
  end

  around_perform do |_job, block|
    block.call
  rescue StandardError => e
    Raven.capture_exception(e)
    raise
  end
  # ...
end

ActionMailer retries

Any configuration in ApplicationJob will have to be duplicated on ActionMailer::MailDeliveryJob (ActionMailer::DeliveryJob in Rails 5.2 or earlier) because ActionMailer uses a custom class, ActionMailer::MailDeliveryJob, which inherits from ActiveJob::Base, rather than your applications ApplicationJob.

You can use an initializer to configure ActionMailer::MailDeliveryJob, for example:

# config/initializers/good_job.rb
ActionMailer::MailDeliveryJob.retry_on StandardError, wait: :exponentially_longer, attempts: Float::INFINITY

# With Sentry (or Bugsnag, Airbrake, Honeybadger, etc.)
ActionMailer::MailDeliveryJob.around_perform do |_job, block|
  block.call
rescue StandardError => e
  Raven.capture_exception(e)
  raise
end

Note, that ActionMailer::MailDeliveryJob is a default since Rails 6.0. Be sure that your app is using that class, as it might also be configured to use (deprecated now) ActionMailer::DeliveryJob.

Timeouts

Job timeouts can be configured with an around_perform:

class ApplicationJob < ActiveJob::Base
  JobTimeoutError = Class.new(StandardError)

  around_perform do |_job, block|
    # Timeout jobs after 10 minutes
    Timeout.timeout(10.minutes, JobTimeoutError) do
      block.call
    end
  end
end

Optimize queues, threads, and processes

By default, GoodJob creates a single thread execution pool that will execute jobs from any queue. Depending on your application's workload, job types, and service level objectives, you may wish to optimize execution resources. For example, providing dedicated execution resources for transactional emails so they are not delayed by long-running batch jobs. Some options:

• Multiple execution pools within a single process:

  $ bundle exec good_job --queues="transactional_messages:2;batch_processing:1;-transactional_messages,batch_processing:2;*" --max-threads=5

  This configuration will result in a single process with 4 isolated thread execution pools. Isolated execution pools are separated with a semicolon (;) and queue names and thread counts with a colon (:)

  • transactional_messages:2: execute jobs enqueued on transactional_messages with up to 2 threads.
  • batch_processing:1 execute jobs enqueued on batch_processing with a single thread.
  • -transactional_messages,batch_processing: execute jobs enqueued on any queue excluding transactional_messages or batch_processing with up to 2 threads.
  • *: execute jobs on any queue on up to 5 threads, as configured by --max-threads=5

  For moderate workloads, multiple isolated thread execution pools offers a good balance between congestion management and economy.

  Configuration can be injected by environment variables too:

  $ GOOD_JOB_QUEUES="transactional_messages:2;batch_processing:1;-transactional_messages,batch_processing:2;*" GOOD_JOB_MAX_THREADS=5 bundle exec good_job

• Multiple processes; for example, on Heroku:

  # Procfile
  
  # Separate dyno types
  worker: bundle exec good_job --max-threads=5
  transactional_worker: bundle exec good_job --queues="transactional_messages" --max-threads=2
  batch_worker: bundle exec good_job --queues="batch_processing" --max-threads=1
  
  # Combined multi-process dyno
  combined_worker: bundle exec good_job --max-threads=5 & bundle exec good_job --queues="transactional_messages" --max-threads=2 & bundle exec good_job --queues="batch_processing" --max-threads=1 & wait -n

  Running multiple processes can optimize for CPU performance at the expense of greater memory and system resource usage.

Keep in mind, queue operations and management is an advanced discipline. This stuff is complex, especially for heavy workloads and unique processing requirements. Good job 👍

Database connections

Each GoodJob execution thread requires its own database connection that is automatically checked out from Rails’s connection pool. Allowing GoodJob to create more threads than available database connections can lead to timeouts and is not recommended. For example:

# config/database.yml
pool: <%= [ENV.fetch("RAILS_MAX_THREADS", 5).to_i, ENV.fetch("GOOD_JOB_MAX_THREADS", 4).to_i].max %>

Execute jobs async / in-process

GoodJob can execute jobs "async" in the same process as the webserver (e.g. bin/rail s). GoodJob's async execution mode offers benefits of economy by not requiring a separate job worker process, but with the tradeoff of increased complexity. Async mode can be configured in two ways:

• Directly configure the ActiveJob adapter:

  # config/environments/production.rb
  config.active_job.queue_adapter = GoodJob::Adapter.new(execution_mode: :async, max_threads: 4, poll_interval: 30)

• Or, when using ...queue_adapter = :good_job, via environment variables:

  $ GOOD_JOB_EXECUTION_MODE=async GOOD_JOB_MAX_THREADS=4 GOOD_JOB_POLL_INTERVAL=30 bin/rails server

Depending on your application configuration, you may need to take additional steps:

• Ensure that you have enough database connections for both web and job execution threads:

  # config/database.yml
  pool: <%= ENV.fetch("RAILS_MAX_THREADS", 5).to_i + ENV.fetch("GOOD_JOB_MAX_THREADS", 4).to_i %>

• When running Puma with workers (WEB_CONCURRENCY > 0) or another process-forking webserver, GoodJob's threadpool schedulers should be stopped before forking, restarted after fork, and cleanly shut down on exit. Stopping GoodJob's scheduler pre-fork is recommended to ensure that GoodJob does not continue executing jobs in the parent/controller process. For example, with Puma:

  # config/puma.rb
  
  before_fork do
    GoodJob.shutdown
  end
  
  on_worker_boot do
    GoodJob.restart
  end
  
  on_worker_shutdown do
    GoodJob.shutdown
  end
  
  MAIN_PID = Process.pid
  at_exit do
    GoodJob.shutdown if Process.pid == MAIN_PID
  end

  GoodJob is compatible with Puma's preload_app! method.

Migrate to GoodJob from a different ActiveJob backend

If your application is already using an ActiveJob backend, you will need to install GoodJob to enqueue and perform newly created jobs and finish performing pre-existing jobs on the previous backend.

1. Enqueue newly created jobs on GoodJob either entirely by setting ActiveJob::Base.queue_adapter = :good_job or progressively via individual job classes:

   # jobs/specific_job.rb
   class SpecificJob < ApplicationJob
     self.queue_adapter = :good_job
     # ...
   end

2. Continue running executors for both backends. For example, on Heroku it's possible to run two processes within the same dyno:

    # Procfile
    # ...
    worker: bundle exec que ./config/environment.rb & bundle exec good_job & wait -n

3. Once you are confident that no unperformed jobs remain in the previous ActiveJob backend, code and configuration for that backend can be completely removed.

Monitor and preserve worked jobs

GoodJob is fully instrumented with ActiveSupport::Notifications.

By default, GoodJob will delete job records after they are run, regardless of whether they succeed or not (raising a kind of StandardError), unless they are interrupted (raising a kind of Exception).

To preserve job records for later inspection, set an initializer:

# config/initializers/good_job.rb
GoodJob.preserve_job_records = true

It is also necessary to delete these preserved jobs from the database after a certain time period:

• For example, in a Rake task:

  GoodJob::Job.finished(1.day.ago).delete_all

• For example, using the good_job command-line utility:

  $ bundle exec good_job cleanup_preserved_jobs --before-seconds-ago=86400

Contribute

Contributions are welcomed and appreciated 🙏

• Review the Prioritized Project Backlog.
• Open a new Issue or contribute to an existing Issue. Questions or suggestions are fantastic.
• Participate according to our Code of Conduct.

Gem development

To run tests:

# Clone the repository locally
$ git clone git@github.com:bensheldon/good_job.git

# Set up the local environment
$ bin/setup

# Run the tests
$ bin/rspec

This gem uses Appraisal to run tests against multiple versions of Rails:

# Install Appraisal(s) gemfiles
$ bundle exec appraisal

# Run tests
$ bundle exec appraisal bin/rspec

For developing locally within another Ruby on Rails project:

# Within Ruby on Rails directory...
$ bundle config local.good_job /path/to/local/git/repository

# Confirm that the local copy is used
$ bundle install

# => Using good_job 0.1.0 from https://github.com/bensheldon/good_job.git (at /Users/You/Projects/good_job@dc57fb0)

Release

Package maintainers can release this gem by running:

# Sign into rubygems
$ gem signin

# Add a .env file with the following:
# CHANGELOG_GITHUB_TOKEN= # Github Personal Access Token

# Update version number, changelog, and create git commit:
$ bundle exec rake release[minor] # major,minor,patch

# ..and follow subsequent directions.

License

The gem is available as open source under the terms of the MIT License.