Merge pull request #37923 from cpruitt/add-config-for-activejob-retry-jitter

Add ActiveJob::Base.default_retry_jitter config option to specify jitter value

activejob/lib/active_job/exceptions.rb

@@ -7,6 +7,11 @@ module ActiveJob
   module Exceptions
     extend ActiveSupport::Concern
 
+    included do
+      class_attribute :default_retry_jitter, instance_accessor: false, instance_predicate: false
+      self.default_retry_jitter = 0.15
+    end
+
     module ClassMethods
       # Catch the exception and reschedule job for re-execution after so many seconds, for a specific number of attempts.
       # If the exception keeps getting raised beyond the specified number of attempts, the exception is allowed to
@@ -49,7 +54,7 @@ module ActiveJob
       #      # Might raise Net::OpenTimeout or Timeout::Error when the remote service is down
       #    end
       #  end
-      def retry_on(*exceptions, wait: 3.seconds, attempts: 5, queue: nil, priority: nil, jitter: 0.15)
+      def retry_on(*exceptions, wait: 3.seconds, attempts: 5, queue: nil, priority: nil, jitter: nil)
         rescue_from(*exceptions) do |error|
           executions = executions_for(exceptions)
           if executions < attempts
@@ -122,7 +127,8 @@ module ActiveJob
     end
 
     private
-      def determine_delay(seconds_or_duration_or_algorithm:, executions:, jitter:)
+      def determine_delay(seconds_or_duration_or_algorithm:, executions:, jitter: nil)
+        jitter ||= self.class.default_retry_jitter
         case seconds_or_duration_or_algorithm
         when :exponentially_longer
           ((executions**4) + (Kernel.rand((executions**4) * jitter))) + 2

activejob/test/cases/exceptions_test.rb

@@ -129,6 +129,31 @@ class ExceptionsTest < ActiveSupport::TestCase
     end
   end
 
+  test "retry jitter uses value from ActiveJob::Base.default_retry_jitter by default" do
+    old_jitter = ActiveJob::Base.default_retry_jitter
+    ActiveJob::Base.default_retry_jitter = 4.0
+
+    travel_to Time.now
+
+    Kernel.stub(:rand, ->(arg) { arg }) do
+      RetryJob.perform_later "ExponentialWaitTenAttemptsError", 5, :log_scheduled_at
+
+      assert_equal [
+        "Raised ExponentialWaitTenAttemptsError for the 1st time",
+        "Next execution scheduled at #{(Time.now + 7.seconds).to_f}",
+        "Raised ExponentialWaitTenAttemptsError for the 2nd time",
+        "Next execution scheduled at #{(Time.now + 82.seconds).to_f}",
+        "Raised ExponentialWaitTenAttemptsError for the 3rd time",
+        "Next execution scheduled at #{(Time.now + 407.seconds).to_f}",
+        "Raised ExponentialWaitTenAttemptsError for the 4th time",
+        "Next execution scheduled at #{(Time.now + 1282.seconds).to_f}",
+        "Successfully completed job"
+      ], JobBuffer.values
+    end
+  ensure
+    ActiveJob::Base.default_retry_jitter = old_jitter
+  end
+
   test "custom wait retrying job" do
     travel_to Time.now
 

guides/source/configuring.md

@@ -807,6 +807,8 @@ There are a few configuration options available in Active Support:
 
 * `config.active_job.log_arguments` controls if the arguments of a job are logged. Defaults to `true`.
 
+* `config.active_job.default_retry_jitter` controls the amount of "jitter" (random variation) applied to the delay time calculated when retrying failed jobs. Defaults to `0.15`.
+
 ### Configuring Action Cable
 
 * `config.action_cable.url` accepts a string for the URL for where

railties/lib/rails/application/configuration.rb

@@ -156,6 +156,10 @@ module Rails
         when "6.1"
           load_defaults "6.0"
 
+          if respond_to?(:active_job)
+            active_job.default_retry_jitter = 0.15
+          end
+
           if respond_to?(:active_record)
             active_record.has_many_inversing = true
           end

railties/test/application/configuration_test.rb

@@ -2262,6 +2262,20 @@ module ApplicationTests
       end
     end
 
+    test "ActiveJob::Base.default_retry_jitter is 0.15 by default" do
+      app "development"
+
+      assert_equal 0.15, ActiveJob::Base.default_retry_jitter
+    end
+
+    test "ActiveJob::Base.default_retry_jitter can be set by config" do
+      app "development"
+
+      Rails.application.config.active_job.default_retry_jitter = 0.22
+
+      assert_equal 0.22, ActiveJob::Base.default_retry_jitter
+    end
+
     test "ActiveJob::Base.return_false_on_aborted_enqueue is true by default" do
       app "development"