Use a queue to manage issue notification emails

I've tested this fairly heavily on a local site, but it's hard to manually cover all the permutations, none of this lends itself to automated testing, and we haven't been spending development effort on automated tests for Project* D7. :/ Therefore, I'd *love* another pair of eyes on this before I commit and deploy this.

Oddly my patch file didn't seem to stick with the last revision. Trying again. WTF?

/me hugs Dave Reid -- no worries.

This is now installed on http://dww7-drupal.redesign.devdrupal.org (along with the patch from #2135095: Follow button does not affect email notifications so that bug should be fixed there, too).

I added a section to the summary about deployment instructions.

If you can log in to the dev site and repair your email address to something valid, confirm it, and set that as your primary address, you should start seeing issue notifications.

I guess we can try to deploy this on a full staging site (maybe git7site is available?) to get a better sense of if it's working properly and to see if it improves the latency of updating an issue in a noticeable way.

A note based on some testing on dww7. This is totally expected, but I wanted to explicitly describe the behavior here in case anyone is confused or thinks this will be a problem:

Now, the follow functionality only counts at the moment that the queue drainer job is running, not at the time the issue update is happening. So, if you add some comments, then unfollow, it's entirely possible/likely that you will *not* see the notifications for those comments, since by the time the queue is being drained, you've already unfollowed.

As I said, I think this makes sense and is not in any way a bug with the implementation, and there's really no good way for us to know if you were following or not when you posted a comment. Although, the act of adding a comment or updating the node will automatically make you follow it again. So, in theory, we should *always* generate a notification on your own comments. Except for the people who think you should *never* get those emails. ;) #667122: Manage e-mail notifications: Add option to not email the person who is making the update

Did more testing on dww7 and didn't find any new problems. Was going to test this on staging, but that site is borked right now. tvn thought we should just plow ahead, push this live, and watch for problems.

http://drupalcode.org/project/project_issue.git/commit/612a7c1

Merged into bzr and deployed to production.

Setup http://localhost:8080/view/D.o/job/drupal.org%20drain%20issue%20notifica...

And finally, ran this on production:

[bender@www1 htdocs]$ drush vset project_issue_notification_queue TRUE
project_issue_notification_queue was set to TRUE.                      [success]

The jenkins job thinks it's sending notifications now:

1 items in queue.                                                           [ok]
Preparing notification for nid: 2141273 cid: 8200665                        [ok]
Processed 1 queued notifications.                                           [ok]
Command dispatch complete                                               [notice]
Finished: SUCCESS

I'll keep a close eye on this for the next hour or so, but so far, it seems to be working okay.

p.s. I asked killes in IRC, and he was happy with this new jenkins job running on www1, not util:

[2:48pm] dww: killes: I just deployed https://drupal.org/node/2139561
[2:48pm] Druplicon: https://drupal.org/node/2139561 => Use a queue to manage issue notification emails #2139561: Use a queue to manage issue notification emails => 7 comments, 5 IRC mentions
[2:48pm] dww: killes: I setup the jenkins job that runs a drush command to drain the notification queue every minute on www1.
[2:48pm] dww: killes: should I configure that job to run on util, instead?  does it matter?
[2:49pm] killes: dww: why do you think it could matter?
[2:50pm] dww: killes: no idea.  I thought y'all might have wanted the emails to be sent from util to reduce the load on the webheads.
[2:50pm] killes: dww: I think the other way is currently true
[2:50pm] dww: killes: you'd rather the sending load on www1?
[2:50pm] killes: dww: the mails are only passed on to OSL.
[2:51pm] killes: dww: it is probably less busy
[2:51pm] dww: killes: great. ;)

It's unclear if that matters at all, but it might be worth opening an issue about optimizing the notification emails, and suggest that as one of the possible solutions to explore.

Thanks,
-Derek