fix: Allow the page view feature to have access to an event buffer (#…

…1315)

src/features/page_view_event/aggregate/index.js

@@ -115,7 +115,6 @@ export class Aggregate extends AggregateBase {
 
   postHarvestCleanup ({ status, responseText, xhr }) {
     const rumEndTime = now()
-    this.blocked = true // this prevents harvester from polling this feature's event buffer (DNE) on interval; in other words, harvests will skip PVE
 
     if (status >= 400 || status === 0) {
       warn(18, status)

src/features/utils/aggregate-base.js

@@ -18,8 +18,7 @@ export class AggregateBase extends FeatureBase {
 
     // This switch needs to be after doOnceForAllAggregate which may new sharedAggregator and reset mainAppKey.
     switch (this.featureName) {
-      // PVE has no need for eventBuffer, and SessionTrace + Replay have their own storage mechanisms.
-      case FEATURE_NAMES.pageViewEvent:
+      // SessionTrace + Replay have their own storage mechanisms.
       case FEATURE_NAMES.sessionTrace:
       case FEATURE_NAMES.sessionReplay:
         break
@@ -28,6 +27,9 @@ export class AggregateBase extends FeatureBase {
       case FEATURE_NAMES.metrics:
         this.events = agentRef.sharedAggregator
         break
+      /** All other features get EventBuffer in the ESM by default. Note: PVE is included here, but event buffer will always be empty so future harvests will still not happen by interval or EOL.
+      This was necessary to prevent race cond. issues where the event buffer was checked before the feature could "block" itself.
+      Its easier to just keep an empty event buffer in place. */
       default:
         this.events = new EventStoreManager(agentRef.mainAppKey, 1)
         break

tests/components/page_view_event/aggregate.test.js

@@ -0,0 +1,32 @@
+import { setupAgent } from '../setup-agent'
+import { Instrument as PageViewEvent } from '../../../src/features/page_view_event/instrument'
+
+let mainAgent, pveAggregate
+
+beforeAll(async () => {
+  mainAgent = setupAgent()
+  mainAgent.info.errorBeacon = undefined // this prevents Harvester from actually running its `send` method
+})
+beforeEach(async () => {
+  const pveInstrument = new PageViewEvent(mainAgent)
+  await new Promise(process.nextTick)
+  pveAggregate = pveInstrument.featAggregate
+})
+
+test('PageViewEvent does not throw on Harvester driven processes', () => {
+  expect(pveAggregate.blocked).toEqual(false)
+  expect(() => pveAggregate.makeHarvestPayload(true)).not.toThrow()
+
+  // The following both don't send anything since PVE buffer is meant to stay empty, so they return false.
+  expect(mainAgent.runtime.harvester.triggerHarvestFor(pveAggregate)).toEqual(false) // mimics what the harvester does on interval
+  expect(mainAgent.runtime.harvester.triggerHarvestFor(pveAggregate, { isFinalHarvest: true })).toEqual(false) // mimics what the harvester does on EoL
+
+  expect(mainAgent.runtime.harvester.triggerHarvestFor(pveAggregate, {
+    directSend: {
+      targetApp: 'someApp',
+      payload: 'blah'
+    },
+    needResponse: true,
+    sendEmptyBody: true
+  })).toEqual(true) // mimics the manual trigger in PVE `sendRum`; this should return true as it actually tries to "send"
+})

tests/unit/features/utils/aggregate-base.test.js

@@ -150,16 +150,16 @@ test('does not initialized Aggregator more than once with multiple features', as
   expect(mainAgent.mainAppKey).toBeUndefined()
 
   new AggregateBase(mainAgent, FEATURE_NAMES.pageViewEvent)
-  expect(EventStoreManager).toHaveBeenCalledTimes(1)
+  expect(EventStoreManager).toHaveBeenCalledTimes(2) // once for runtime.sharedAgg + once for PVE.events
   expect(EventStoreManager).toHaveBeenCalledWith(mainAgent.mainAppKey, 2) // 2 = initialize EventAggregator
   expect(mainAgent.mainAppKey).toBeTruthy()
   expect(mainAgent.sharedAggregator).toBeTruthy()
 
   new AggregateBase(mainAgent, FEATURE_NAMES.jserrors) // this feature should be using that same aggregator as its .events
-  expect(EventStoreManager).toHaveBeenCalledTimes(1)
+  expect(EventStoreManager).toHaveBeenCalledTimes(2)
 
   new AggregateBase(mainAgent, FEATURE_NAMES.pageViewTiming) // PVT should use its own EventStoreManager
-  expect(EventStoreManager).toHaveBeenCalledTimes(2)
+  expect(EventStoreManager).toHaveBeenCalledTimes(3)
   expect(EventStoreManager).toHaveBeenCalledWith(mainAgent.mainAppKey, 1) // 1 = initialize EventBuffer
 })
 
@@ -175,10 +175,9 @@ test('does initialize separate Aggregators with multiple agents', async () => {
 
   new AggregateBase(mainAgent, FEATURE_NAMES.pageViewEvent)
   new AggregateBase(mainAgent2, FEATURE_NAMES.pageViewEvent)
-  expect(EventStoreManager).toHaveBeenCalledTimes(2)
-  expect(EventStoreManager).not.toHaveBeenCalledWith(expect.any(Object), 1)
+  expect(EventStoreManager).toHaveBeenCalledTimes(4) // runtime.sharedAgg + PVE.events but multiply by having 2 agents
 
   new AggregateBase(mainAgent, FEATURE_NAMES.jserrors) // still does not initialize sharedAgg again on the same agent
   new AggregateBase(mainAgent2, FEATURE_NAMES.jserrors)
-  expect(EventStoreManager).toHaveBeenCalledTimes(2)
+  expect(EventStoreManager).toHaveBeenCalledTimes(4)
 })