add framework for post update pushes to pubsub

app/models/post.rb

@@ -1383,15 +1383,9 @@ class Post < ActiveRecord::Base
     end
 
     def notify_pubsub
-      return
       return unless Danbooru.config.google_api_project
 
-      pubsub = Google::Apis::PubsubV1::PubsubService.new
-      pubsub.authorization = Google::Auth.get_application_default([Google::Apis::PubsubV1::AUTH_PUBSUB])
-      topic = "projects/#{Danbooru.config.google_api_project}/topics/post_updates"
-      request = Google::Apis::PubsubV1::PublishRequest.new(messages: [])
-      request.messages << Google::Apis::PubsubV1::Message.new(data: id.to_s)
-      pubsub.publish_topic(topic, request)
+      PostUpdate.insert(id)
     end
   end
 

app/models/post_update.rb

@@ -0,0 +1,23 @@
+class PostUpdate
+  def self.insert(post_id)
+    ActiveRecord::Base.execute_sql("insert into post_updates (post_id) values (?) on conflict do nothing", post_id)
+  end
+
+  def self.get
+    ActiveRecord::Base.select_values_sql("delete from post_updates returning post_id")
+  end
+
+  def self.push
+    return unless Danbooru.config.google_api_project
+
+    pubsub = Google::Apis::PubsubV1::PubsubService.new
+    pubsub.authorization = Google::Auth.get_application_default([Google::Apis::PubsubV1::AUTH_PUBSUB])
+    topic = "projects/#{Danbooru.config.google_api_project}/topics/post_updates"
+    post_ids = get()
+
+    post_ids.in_groups_of(1_000, false).each do |group|
+      request = Google::Apis::PubsubV1::PublishRequest.new(messages: group.map {|x| Google::Apis::PubsubV1::Message.new(data: x.to_s)})
+      pubsub.publish_topic(topic, request)
+    end
+  end
+end