retry.rb in rocketjob-6.2.0

- old
+ new

@@ -24,18 +24,55 @@
     # MyCronJob.create!(retry_limit: 10)
     #
     # # Disable retries for this job instance.
     # MyCronJob.create!(retry_limit: 0)
     #
+    # Below is a table of the delay for each retry attempt, as well as the _total_ duration spent retrying a job for
+    # the specified number of retries, excluding actual processing time.
+    #
+    # |---------|------------|----------------|
+    # | Attempt |      Delay | Total Duration |
+    # |---------|------------|----------------|
+    # |      01 |     6.000s |         6.000s |
+    # |      02 |    21.000s |        27.000s |
+    # |      03 |     1m 26s |         1m 53s |
+    # |      04 |     4m 21s |         6m 14s |
+    # |      05 |    10m 30s |        16m 44s |
+    # |      06 |    21m 41s |        38m 25s |
+    # |      07 |     40m 6s |        20h 18m |
+    # |      08 |     20h 8m |        21h 26m |
+    # |      09 |    20h 49m |        23h 16m |
+    # |      10 |    21h 46m |          2h 3m |
+    # |      11 |     23h 4m |          6h 7m |
+    # |      12 |     0h 45m |        11h 52m |
+    # |      13 |     2h 56m |     1d 19h 48m |
+    # |      14 |     5h 40m |      1d 6h 29m |
+    # |      15 |      9h 3m |     2d 20h 33m |
+    # |      16 |    13h 12m |     2d 14h 45m |
+    # |      17 |    18h 12m |     3d 13h 57m |
+    # |      18 |   1d 0h 9m |      5d 19h 7m |
+    # |      19 |  1d 7h 12m |      6d 7h 19m |
+    # |      20 | 1d 15h 26m |      8d 3h 46m |
+    # |      21 |   2d 1h 1m |     10d 9h 47m |
+    # |      22 |  2d 12h 4m |     13d 2h 51m |
+    # |      23 |  3d 0h 44m |     16d 8h 35m |
+    # |      24 |  3d 15h 9m |     20d 4h 45m |
+    # |      25 |  4d 7h 30m |     24d 17h 16 |
+    # |      26 |  5d 1h 56m |     30d 0h 12m |
+    # |      27 | 6d 22h 37m |     36d 3h 49m |
+    # |      28 | 7d 21h 44m |     43d 6h 34m |
+    # |      29 | 8d 23h 28m |     51d 11h 2m |
+    # |      30 |   9d 4h 0m |     61d 20h 2m |
+    # |---------|------------|----------------|
     module Retry
       extend ActiveSupport::Concern
 
       included do
         after_fail :rocket_job_retry
 
-        # Maximum number of times to retry this job
-        # 25 is approximately 3 weeks of retries
+        # Maximum number of times to retry this job.
+        # The default of 25 is almost 25 days of retries.
         field :retry_limit, type: Integer, default: 25, class_attribute: true, user_editable: true, copy_on_restart: true
 
         # List of times when this job failed
         field :failed_at_list, type: Array, default: []
 
@@ -71,13 +108,26 @@
         self.completed_at = nil
         self.exception    = nil unless rocket_job_retry_on_fail?
         self.worker_name  = nil
       end
 
-      # Returns [Time] when to retry this job at
-      # Same basic formula as Delayed Job
+      # Returns [Integer] the number of seconds after which to retry this failed job.
+      # Uses an exponential back-off algorithm to prevent overloading the failed resource.
+      #
+      # For example, to see the durations for the first 25 retries:
+      #   count = 25
+      #   intervals = (1..count).map { |attempt| attempt**4 + 5 }
+      #
+      # Display the above intervals as human readable durations:
+      #   intervals.map { |seconds| RocketJob.seconds_as_duration(seconds) }
+      #
+      # Then sum the total duration in seconds:
+      #   RocketJob.seconds_as_duration(intervals.sum)
+      #
+      # Or, to see the total durations based on the number of retries:
+      #   (0..count).map{|i| "#{i+1} ==> #{RocketJob.seconds_as_duration(intervals[0..i].sum)}"}
       def rocket_job_retry_seconds_to_delay
-        (rocket_job_failure_count**4) + 15 + (rand(30) * (rocket_job_failure_count + 1))
+        rocket_job_failure_count**4 + 5
       end
     end
   end
 end