github.com/ferranbt/nomad@v0.9.3-0.20190607002617-85c449b7667c/ui/app/services/stats-trackers-registry.js (about)

     1  import { computed } from '@ember/object';
     2  import Service, { inject as service } from '@ember/service';
     3  import { LRUMap } from 'lru_map';
     4  import NodeStatsTracker from 'nomad-ui/utils/classes/node-stats-tracker';
     5  import AllocationStatsTracker from 'nomad-ui/utils/classes/allocation-stats-tracker';
     6  
     7  // An unbounded number of stat trackers is a great way to gobble up all the memory
     8  // on a machine. This max number is unscientific, but aims to balance losing
     9  // stat trackers a user is likely to return to with preventing gc from freeing
    10  // memory occupied by stat trackers a user is likely to no longer care about
    11  const MAX_STAT_TRACKERS = 10;
    12  let registry;
    13  
    14  const exists = (tracker, prop) =>
    15    tracker.get(prop) && !tracker.get(prop).isDestroyed && !tracker.get(prop).isDestroying;
    16  
    17  export default Service.extend({
    18    token: service(),
    19  
    20    init() {
    21      // The LRUMap limits the number of trackers tracked by making room for
    22      // new entries beyond the limit by removing the least recently used entry.
    23      registry = new LRUMap(MAX_STAT_TRACKERS);
    24    },
    25  
    26    // A read-only way of getting a reference to the registry.
    27    // Since this could be overwritten by a bad actor, it isn't
    28    // used in getTracker
    29    registryRef: computed(() => registry),
    30  
    31    getTracker(resource) {
    32      if (!resource) return;
    33  
    34      const type = resource && resource.constructor.modelName;
    35      const key = `${type}:${resource.get('id')}`;
    36      const Constructor = type === 'node' ? NodeStatsTracker : AllocationStatsTracker;
    37      const resourceProp = type === 'node' ? 'node' : 'allocation';
    38  
    39      const cachedTracker = registry.get(key);
    40      if (cachedTracker) {
    41        // It's possible for the resource on a cachedTracker to have been
    42        // deleted. Rebind it if that's the case.
    43        if (!exists(cachedTracker, resourceProp)) cachedTracker.set(resourceProp, resource);
    44        return cachedTracker;
    45      }
    46  
    47      const tracker = Constructor.create({
    48        fetch: url => this.token.authorizedRequest(url),
    49        [resourceProp]: resource,
    50      });
    51  
    52      registry.set(key, tracker);
    53  
    54      return tracker;
    55    },
    56  });