DEV: Allow rebakes to generate optimized images at the same time

Previously only Sidekiq was allowed to generate more than one optimized image at the same time per machine. This adds an easy mechanism to allow the same in rake tasks and other tools.

app/models/optimized_image.rb

@@ -14,15 +14,24 @@ class OptimizedImage < ActiveRecord::Base
     # this can very easily lead to runaway CPU so slowing it down is beneficial and it is hijacked
     #
     # we can not afford this blocking in Sidekiq cause it can lead to starvation
-    if Sidekiq.server?
+    if lock_per_machine?
-      DistributedMutex.synchronize("optimized_image_#{upload_id}_#{width}_#{height}") { yield }
-    else
       DistributedMutex.synchronize("optimized_image_host_#{@hostname}") do
         DistributedMutex.synchronize("optimized_image_#{upload_id}_#{width}_#{height}") { yield }
       end
+    else
+      DistributedMutex.synchronize("optimized_image_#{upload_id}_#{width}_#{height}") { yield }
     end
   end
 
+  def self.lock_per_machine?
+    return @lock_per_machine if defined?(@lock_per_machine)
+    @lock_per_machine = !Sidekiq.server?
+  end
+
+  def self.lock_per_machine=(value)
+    @lock_per_machine = value
+  end
+
   def self.create_for(upload, width, height, opts = {})
     return if width <= 0 || height <= 0
     return if upload.try(:sha1).blank?

lib/tasks/import.rake

@@ -720,63 +720,48 @@ desc "Rebake posts that contain polls"
 task "import:rebake_uncooked_posts_with_polls" => :environment do
   log "Rebaking posts with polls"
 
-  Jobs.run_immediately!
+  posts = Post.where("EXISTS (SELECT 1 FROM polls WHERE polls.post_id = posts.id)")
 
-  posts =
+  rebake_posts(posts)
-    Post.where("EXISTS (SELECT 1 FROM polls WHERE polls.post_id = posts.id)").where(
-      "baked_version <> ? or baked_version IS NULL",
-      Post::BAKED_VERSION,
-    )
-
-  max_count = posts.count
-  current_count = 0
-
-  posts.find_each(order: :desc) do |post|
-    post.rebake!
-    current_count += 1
-    print "\r%7d / %7d" % [current_count, max_count]
-  end
 end
 
 desc "Rebake posts that contain events"
 task "import:rebake_uncooked_posts_with_events" => :environment do
   log "Rebaking posts with events"
 
-  Jobs.run_immediately!
-
   posts =
     Post.where(
       "EXISTS (SELECT 1 FROM discourse_post_event_events WHERE discourse_post_event_events.id = posts.id)",
-    ).where("baked_version <> ? or baked_version IS NULL", Post::BAKED_VERSION)
+    )
 
-  max_count = posts.count
+  rebake_posts(posts)
-  current_count = 0
-
-  posts.find_each(order: :desc) do |post|
-    post.rebake!
-    current_count += 1
-    print "\r%7d / %7d" % [current_count, max_count]
-  end
 end
 
 desc "Rebake posts that have tag"
 task "import:rebake_uncooked_posts_with_tag", [:tag_name] => :environment do |_task, args|
   log "Rebaking posts with tag"
 
-  Jobs.run_immediately!
-
   posts =
     Post.where(
       "EXISTS (SELECT 1 FROM topic_tags JOIN tags ON tags.id = topic_tags.tag_id WHERE topic_tags.topic_id = posts.topic_id AND tags.name = ?)",
       args[:tag_name],
-    ).where("baked_version <> ? or baked_version IS NULL", Post::BAKED_VERSION)
+    )
+
+  rebake_posts(posts)
+end
+
+def rebake_posts(posts)
+  Jobs.run_immediately!
+  OptimizedImage.lock_per_machine = false
 
   max_count = posts.count
   current_count = 0
 
-  posts.find_each(order: :desc) do |post|
+  posts
-    post.rebake!
+    .where("baked_version <> ? or baked_version IS NULL", Post::BAKED_VERSION)
-    current_count += 1
+    .find_each(order: :desc) do |post|
-    print "\r%7d / %7d" % [current_count, max_count]
+      post.rebake!
-  end
+      current_count += 1
+      print "\r%7d / %7d" % [current_count, max_count]
+    end
 end

lib/tasks/posts.rake

@@ -13,6 +13,9 @@ task "posts:rebake_uncooked_posts" => :environment do
   # this rake task without worrying about your sidekiq imploding
   Jobs.run_immediately!
 
+  # don't lock per machine, we want to be able to run this from multiple consoles
+  OptimizedImage.lock_per_machine = false
+
   ENV["RAILS_DB"] ? rebake_uncooked_posts : rebake_uncooked_posts_all_sites
 end
 

script/bulk_import/uploads_importer.rb

@@ -6,13 +6,6 @@ require "etc"
 require "sqlite3"
 require "colored2"
 
-# hack so that OptimizedImage.lock beliefs that it's running in a Sidekiq job
-module Sidekiq
-  def self.server?
-    true
-  end
-end
-
 module BulkImport
   class UploadsImporter
     TRANSACTION_SIZE = 1000
@@ -356,6 +349,9 @@ module BulkImport
       avatar_upload_ids = Set.new
       max_count = 0
 
+      # allow more than 1 thread to optimized images at the same time
+      OptimizedImage.lock_per_machine = false
+
       init_threads << Thread.new do
         query("SELECT id FROM optimized_images", @output_db).tap do |result_set|
           result_set.each { |row| optimized_upload_ids << row["id"] }