[katello-devel] Pre-save and post-save queues in glue layer

[Ivan Nečas]

Hi,

After GPG keys orchestration, I'm working on another task where we need 
to do some action after saving a record to our database: we create 
environment in Katello and then in Candlepin (we are sending there our 
environment_id.

Like it was pointed out before, in current state all the orchestration 
happens before the record is saved:

     def on_save
       process queue
       yield if block_given?
       @orchestration_for = nil
     end

I suggest to rename our current queue to pre_queue (which means to 
happen before saving) and post_queue (after saving). So the on_save 
around filter would look like this:

     def on_save
       process pre_queue
       yield if block_given?
       process post_queue
       @orchestration_for = nil
     end

I've already tested it in my branch, and it looks it serves our 
purposes. We don't have to worry about record being created before some 
orchestrations fails: on_save runs whole in transaction and when 
something is wrong, it rolls back the insertion. From my sql log after 
simulating an error after saving:

   SQL (6.7ms)  INSERT INTO "providers" ("created_at", "updated_at", 
"organization_id", "provider_type", "repository_url", "name", 
"description") VALUES ('2012-01-26 08:52:44.664467', '2012-01-26 
08:52:44.664467', 1, 'Custom', NULL, 'katello', NULL) RETURNING "id"
   SQL (0.1ms)  ROLLBACK


I would like to get some team ACK before actually implementing the whole 
change, incluiding renaming the original queue. Any suggestions on 
better naming etc. welcomed.

-- Ivan