From 5bfd1d0ddd08377a34dfd8ce5047174edfedeecb Mon Sep 17 00:00:00 2001
From: Michael Lange <dingoeatingfuzz@gmail.com>
Date: Fri, 29 Mar 2019 16:09:14 -0700
Subject: [PATCH] Reattach resources to stats trackers in the event they were
 destroyed

---
 ui/app/services/stats-trackers-registry.js    | 15 ++++--
 .../services/stats-trackers-registry-test.js  | 47 +++++++++++++++++++
 2 files changed, 58 insertions(+), 4 deletions(-)

diff --git a/ui/app/services/stats-trackers-registry.js b/ui/app/services/stats-trackers-registry.js
index 0233c74d3..31f5c383b 100644
--- a/ui/app/services/stats-trackers-registry.js
+++ b/ui/app/services/stats-trackers-registry.js
@@ -11,6 +11,9 @@ import AllocationStatsTracker from 'nomad-ui/utils/classes/allocation-stats-trac
 const MAX_STAT_TRACKERS = 10;
 let registry;
 
+const exists = (tracker, prop) =>
+  tracker.get(prop) && !tracker.get(prop).isDestroyed && !tracker.get(prop).isDestroying;
+
 export default Service.extend({
   token: service(),
 
@@ -30,13 +33,17 @@ export default Service.extend({
 
     const type = resource && resource.constructor.modelName;
     const key = `${type}:${resource.get('id')}`;
-
-    const cachedTracker = registry.get(key);
-    if (cachedTracker) return cachedTracker;
-
     const Constructor = type === 'node' ? NodeStatsTracker : AllocationStatsTracker;
     const resourceProp = type === 'node' ? 'node' : 'allocation';
 
+    const cachedTracker = registry.get(key);
+    if (cachedTracker) {
+      // It's possible for the resource on a cachedTracker to have been
+      // deleted. Rebind it if that's the case.
+      if (!exists(cachedTracker, resourceProp)) cachedTracker.set(resourceProp, resource);
+      return cachedTracker;
+    }
+
     const tracker = Constructor.create({
       fetch: url => this.get('token').authorizedRequest(url),
       [resourceProp]: resource,
diff --git a/ui/tests/unit/services/stats-trackers-registry-test.js b/ui/tests/unit/services/stats-trackers-registry-test.js
index 9916fafcf..559590410 100644
--- a/ui/tests/unit/services/stats-trackers-registry-test.js
+++ b/ui/tests/unit/services/stats-trackers-registry-test.js
@@ -1,6 +1,7 @@
 import EmberObject from '@ember/object';
 import { getOwner } from '@ember/application';
 import Service from '@ember/service';
+import { run } from '@ember/runloop';
 import wait from 'ember-test-helpers/wait';
 import { moduleFor, test } from 'ember-qunit';
 import Pretender from 'pretender';
@@ -104,6 +105,52 @@ test('Has a max size', function(assert) {
   assert.ok(ref.limit < Infinity, `A limit (${ref.limit}) is set`);
 });
 
+test('Registry re-attaches deleted resources to cached trackers', function(assert) {
+  const registry = this.subject();
+  const id = 'some-id';
+
+  const node1 = mockNode.create({ id });
+  let tracker = registry.getTracker(node1);
+
+  assert.ok(tracker.get('node'), 'The tracker has a node');
+
+  tracker.set('node', null);
+  assert.notOk(tracker.get('node'), 'The tracker does not have a node');
+
+  tracker = registry.getTracker(node1);
+  assert.equal(
+    tracker.get('node'),
+    node1,
+    'The node was re-attached to the tracker after calling getTracker again'
+  );
+});
+
+test('Registry re-attaches destroyed resources to cached trackers', function(assert) {
+  const registry = this.subject();
+  const id = 'some-id';
+
+  const node1 = mockNode.create({ id });
+  let tracker = registry.getTracker(node1);
+
+  assert.ok(tracker.get('node'), 'The tracker has a node');
+
+  run(() => {
+    node1.destroy();
+  });
+
+  return wait().then(() => {
+    assert.ok(tracker.get('node').isDestroyed, 'The tracker node is destroyed');
+
+    const node2 = mockNode.create({ id });
+    tracker = registry.getTracker(node2);
+    assert.equal(
+      tracker.get('node'),
+      node2,
+      'Since node1 was destroyed but it matches the tracker of node2, node2 is attached to the tracker'
+    );
+  });
+});
+
 test('Removes least recently used when something needs to be removed', function(assert) {
   const registry = this.subject();
   const activeNode = mockNode.create({ id: 'active' });