Add Background Jobs

add-background-jobs

Use this workflow when integrating background jobs in Hanami 2.x.

Core principle: Background jobs are registered components. They are enqueued from Actions and executed asynchronously.

Core Process

1. [Register Job Adapter] — Load skill: register-provider

   • Choose adapter: Sidekiq, GoodJob, or custom
   • Create config/providers/background_jobs.rb
   • Register the adapter client in the start block
   • Handoff condition: Adapter accessible via Deps["jobs.client"]

   # config/providers/background_jobs.rb
   Hanami.app.register_provider(:background_jobs) do
     start do
       require "sidekiq"
       Sidekiq.configure_client do |config|
         config.redis = { url: target[:settings].redis_url }
       end
       register("jobs.client", Sidekiq::Client)
     end
   end
   

   Validation: Verify registration with MyApp::App["jobs.client"] in a Hanami console or container lookup spec. It should return Sidekiq::Client without raising Dry::Container::Error.

2. [Inject into Action] — Load skill: inject-dependencies

   • Inject job adapter into Action
   • Handoff condition: Adapter injectable

   class Create < MyApp::Action
     include Deps["jobs.client", "repos.user_repo"]
   end
   

3. [Enqueue from Action] — Load skill: create-action

   • Define job class
   • Enqueue job from Action after successful operation
   • Handle enqueue failures gracefully — rescue enqueue errors and log them; do not crash the Action
   • Handoff condition: Jobs are enqueued and executed

   # app/jobs/welcome_email.rb
   module MyApp
     module Jobs
       class WelcomeEmail
         include Sidekiq::Worker
   
         def perform(user_id)
           user = user_repo.by_id(user_id).one
           mailer.deliver(to: user.email, subject: "Welcome!")
         end
       end
     end
   end
   

   class Create < MyApp::Action
     def handle(request, response)
       result = create_user.call(request.params[:user])
       case result
       in Success(user)
         jobs.client.push("class" => "MyApp::Jobs::WelcomeEmail", "args" => [user.id])
         response.status = 201
       in Failure(error)
         response.status = 422
       end
     rescue => e
       Hanami.logger.error("Job enqueue failed: #{e.message}")
       response.status = 201 # Still succeed; enqueue failure is non-fatal
     end
   end
   

   Validation: Confirm jobs are being enqueued by checking the Sidekiq dashboard (/sidekiq) or inspecting the Redis queue directly (Sidekiq::Queue.new.size). In tests, use Sidekiq::Testing.fake! and assert on MyApp::Jobs::WelcomeEmail.jobs.

4. [Write Job Specs] — Load skill: write-action-spec

   • Test job class in isolation with stubbed dependencies
   • Test that Action enqueues the job
   • Handoff condition: Job specs pass

   # spec/unit/my_app/jobs/welcome_email_spec.rb
   RSpec.describe MyApp::Jobs::WelcomeEmail do
     subject(:job) { described_class.new }
   
     let(:user_repo) { instance_double(MyApp::Repos::UserRepo) }
     let(:mailer)    { instance_double(MyApp::Mailers::Welcome) }
     let(:user)      { instance_double(MyApp::Entities::User, id: 42, email: "user@example.com") }
   
     before do
       allow(user_repo).to receive(:by_id).with(42).and_return(double(one: user))
       allow(mailer).to receive(:deliver)
       job.instance_variable_set(:@user_repo, user_repo)
       job.instance_variable_set(:@mailer, mailer)
     end
   
     it "delivers a welcome email to the user" do
       job.perform(42)
       expect(mailer).to have_received(:deliver).with(to: "user@example.com", subject: "Welcome!")
     end
   end
   
   # spec/requests/users/create_spec.rb (enqueue assertion)
   RSpec.describe "POST /users" do
     before { Sidekiq::Testing.fake! }
     after  { Sidekiq::Worker.clear_all }
   
     it "enqueues a WelcomeEmail job on success" do
       expect {
         post "/users", params: { user: { name: "Alice", email: "alice@example.com" } }
       }.to change(MyApp::Jobs::WelcomeEmail.jobs, :size).by(1)
   
       expect(last_response.status).to eq(201)
     end
   end
   

Common Pitfalls

• Synchronous execution of deferrable work — Use jobs for emails, notifications, exports, or anything that can be deferred.
• Missing enqueue error handling — Rescue enqueue errors and log them. Do not crash the Action on transient queue failures.
• Direct container access in jobs — Inject dependencies via DI container; do not access the container directly inside jobs.
• Passing complex objects as job arguments — Jobs serialize to JSON. Pass IDs or simple scalar data, never Ruby objects.
• Missing job tests — Always test the job class in isolation and verify the Action enqueues correctly.
• Jobs not registered in DI container — The job adapter client must be registered as a provider before it can be injected.