Delayed::Job

Delayed::Job is created by the excellent folks at Shopify and one of the most popular background processors for Ruby and Rails.

The AppSignal gem detects Delayed Job when it's present and hooks into the standard Delayed Job callbacks. No further action is required to enable integration.

This integration aims to support all different Delayed::Job support enqueuing methods. Some methods may have some limitations and customization options.

Classes with #perform methods

Delayed Job supports enqueuing jobs based on instances of classes or structs that listen to a perform instance method, when enqueued with Delayed::Job.enqueue. AppSignal will use the object's class name as the action naming, appending #perform to the action name. A job for StructJob is reported as StructJob#perform.

class StructJob < Struct.new(:id)
  def perform
    # Do stuff
  end
end
 
Delayed::Job.enqueue(StructJob.new("id"))
# Reported as "StructJob#perform"

Note that this method of enqueuing does not support arguments as a whole object is enqueued. Job objects are serialized when enqueued and deserialized when processed. AppSignal does not read the state of the deserialized object. The argument id for the StructJob in the example above is not reported.

Jobs using display_name

Delayed Job allows any class to define its own display_name. This display_name value can interfere with AppSignal's reporting if it is built using dynamic values, such as the arguments given to the job.

If the display_name method return value does not return a String with the ClassName#method_name format, AppSignal treats each job as a separate entity, creating many Incidents and notifications. This breaks the grouping AppSignal does for these jobs, resulting in AppSignal reporting many unique variations of incidents for the job, and unusable metrics in graphs.

To prevent this from happening, define an appsignal_name method that returns a job name using the ClassName#method_name format. This way the jobs will be grouped correctly again.

class StructJobWithName < Struct.new(:id)
  def perform
    # Do stuff
  end
 
  # This returns an unique job name, creating new incidents and graphs for each
  # unique job name.
  def display_name
    "StructJobWithName-#{id}"
  end
 
  # This will group the jobs back to a single entity, allowing incidents
  # and graphs to work properly.
  def appsignal_name
    "StructJobWithName#perform"
  end
end
 
Delayed::Job.enqueue(StructJobWithName.new("id"))
# Reported as "StructJobWithName#perform"

Delay method call support

Method calls queued with the delay extension will be reported with an action name similar to how they are called.

The arguments given to the delayed method will be reported as the arguments for the job.

Post.delay.archive_all("some selector")
# Reported as "Post.archive_all"
 
Post.create(:title => "Post title").delay.send_mail("mail subject")
# Reported as "Post#send_mail"

Delayed::Job.enqueue support

Custom jobs objects enqueued with Delayed::Job.enqueue will be reported as normal, but will not report arguments. A whole object is given to Delayed::Job, and serialized into YAML and back. We can't detect arguments in this scenario.

Delayed::Job.enqueue job_object

Active Job support

The Delayed Job integration is compatible with Active Job. It will report queue times in graphs, queues and priorities if set on the job.

Upgrade to version 2.11.0 of the Ruby gem or newer for improved support.

Changes to the integration

Queue time

In AppSignal for Ruby gem 2.3.0 a change was made to the queue time registration. In PR #297 the start time of the job was used rather than the creation time of the job.

This means that the time from when a job was created until the time it should start is no longer registered as queue time. This will prevent very long queue times from skewing the queue time graphs on AppSignal.com.

Example applications

Below is a list of example apps available to test the Delayed::Job integration with:

• AppSignal + Rails 5 + Delayed::Job
  • The example shows how to set up AppSignal with Delayed::Job and Rails. In the README file it lists all known and tested methods of enqueuing jobs that AppSignal supports.