DEV: Post detection on a schedule (#292)

The job was originally created as a regular job for testing. With this commit it will be a scheduled job gated by SiteSetting.experimental_content_translation.

Author: nattsw

app/jobs/regular/detect_posts_locale.rb renamed to app/jobs/scheduled/posts_locale_detection_backfill.rb

@@ -1,24 +1,24 @@
 # frozen_string_literal: true
 
 module Jobs
-  class DetectPostsLocale < ::Jobs::Base
+  class PostsLocaleDetectionBackfill < ::Jobs::Scheduled
+    every 5.minutes
     cluster_concurrency 1
-    sidekiq_options retry: false
-
-    BATCH_SIZE = 50
 
     def execute(args)
       return unless SiteSetting.translator_enabled
       return unless SiteSetting.experimental_content_translation
+      return if SiteSetting.automatic_translation_backfill_rate == 0
 
+      limit = SiteSetting.automatic_translation_backfill_rate
       posts =
         Post
           .where(locale: nil)
           .where(deleted_at: nil)
           .where("posts.user_id > 0")
           .where.not(raw: [nil, ""])
           .order(updated_at: :desc)
-          .limit(BATCH_SIZE)
+          .limit(limit)
       return if posts.empty?
 
       posts.each do |post|

spec/jobs/detect_posts_locale_spec.rb renamed to spec/jobs/posts_locale_detection_backfill_spec.rb

@@ -1,12 +1,13 @@
 # frozen_string_literal: true
 
-describe Jobs::DetectPostsLocale do
+describe Jobs::PostsLocaleDetectionBackfill do
   fab!(:post) { Fabricate(:post, locale: nil) }
   subject(:job) { described_class.new }
 
   before do
     SiteSetting.translator_enabled = true
     SiteSetting.experimental_content_translation = true
+    SiteSetting.automatic_translation_backfill_rate = 100
   end
 
   it "does nothing when translator is disabled" do
@@ -43,16 +44,13 @@
     post_2.update!(updated_at: 2.day.ago)
     post_3.update!(updated_at: 4.day.ago)
 
-    original_batch = described_class::BATCH_SIZE
-    described_class.const_set(:BATCH_SIZE, 1)
+    SiteSetting.automatic_translation_backfill_rate = 1
 
     DiscourseTranslator::PostLocaleDetector.expects(:detect_locale).with(post_2).once
     DiscourseTranslator::PostLocaleDetector.expects(:detect_locale).with(post).never
     DiscourseTranslator::PostLocaleDetector.expects(:detect_locale).with(post_3).never
 
     job.execute({})
-  ensure
-    described_class.const_set(:BATCH_SIZE, original_batch)
   end
 
   it "skips bot posts" do