From f6122547d77444a027119c3c2b7f2602a5acde53 Mon Sep 17 00:00:00 2001
From: epriestley <git@epriestley.com>
Date: Wed, 24 Oct 2018 09:26:24 -0700
Subject: [PATCH] When a lease triggers a resource allocation for a resource
 which must activate, awaken the lease task after the resource activates

Summary:
Depends on D19753. Ref T13210. This is a small optimization that saves us from waiting up to 15 seconds for a yield.

When there are no Working Copy resources and a new lease comes in, we'll allocate one and yield until it activates.

If activating it (SSH'ing and running `git clone`) takes less than 15 seconds, the resource will activate (say, at T+4) but the lease won't update again for a while (say, until T+15). This leaves us with a pointless wait (in this example, we're sitting around for 9 seconds when we could move forward).

To improve this a little bit, let resources wake up the lease update tasks that triggered allocation after they activate. In the best case, that task runs ~15 seconds sooner. In the worst case, the awaken is just a no-op.

With a more-full queue, this has a smaller effect (it's likely something else will run and be able to use the resource in those 9 seconds).

With already-activated resources, this has no effect (when resources are already activated, we can lease immediately).

Test Plan:
  - Cleaned up all working copy resources.
  - Requested a new "A" working copy.
  - Before patch: got a working copy after 17-18 seconds, most of which was spent yielded.
  - After patch: got a working copy after 3-4 seconds.

Reviewers: amckinley

Reviewed By: amckinley

Subscribers: PHID-OPKG-gm6ozazyms6q6i22gyam

Maniphest Tasks: T13210

Differential Revision: https://secure.phabricator.com/D19754
---
 .../drydock/worker/DrydockLeaseUpdateWorker.php            | 7 +++++++
 .../drydock/worker/DrydockResourceUpdateWorker.php         | 5 +++++
 2 files changed, 12 insertions(+)

diff --git a/src/applications/drydock/worker/DrydockLeaseUpdateWorker.php b/src/applications/drydock/worker/DrydockLeaseUpdateWorker.php
index 5506e3cb9f..3ff9900239 100644
--- a/src/applications/drydock/worker/DrydockLeaseUpdateWorker.php
+++ b/src/applications/drydock/worker/DrydockLeaseUpdateWorker.php
@@ -599,6 +599,13 @@ final class DrydockLeaseUpdateWorker extends DrydockWorker {
         'DrydockResourceUpdateWorker',
         array(
           'resourcePHID' => $resource->getPHID(),
+
+          // This task will generally yield while the resource activates, so
+          // wake it back up once the resource comes online. Most of the time,
+          // we'll be able to lease the newly activated resource.
+          'awakenOnActivation' => array(
+            $this->getCurrentWorkerTaskID(),
+          ),
         ),
         array(
           'objectPHID' => $resource->getPHID(),
diff --git a/src/applications/drydock/worker/DrydockResourceUpdateWorker.php b/src/applications/drydock/worker/DrydockResourceUpdateWorker.php
index 817fbaddee..14ef8e4936 100644
--- a/src/applications/drydock/worker/DrydockResourceUpdateWorker.php
+++ b/src/applications/drydock/worker/DrydockResourceUpdateWorker.php
@@ -170,6 +170,11 @@ final class DrydockResourceUpdateWorker extends DrydockWorker {
     $blueprint = $resource->getBlueprint();
     $blueprint->activateResource($resource);
     $this->validateActivatedResource($blueprint, $resource);
+
+    $awaken_ids = $this->getTaskDataValue('awakenOnActivation');
+    if (is_array($awaken_ids) && $awaken_ids) {
+      PhabricatorWorker::awakenTaskIDs($awaken_ids);
+    }
   }