feat: Use new shared session for Session Trace feature - NEWRELIC-8662 (

#545)

Co-authored-by: Patrick Housley <[email protected]>
Co-authored-by: Jordan Porter <[email protected]>

src/common/constants/shared-channel.js

@@ -0,0 +1,13 @@
+/**
+ * @file Keeps an object alive that is passed to all feature aggregate modules.
+ * The purpose is to have a way for communication and signals to relay across features at runtime.
+ * This object can hold any arbitrary values and should be treated as on-the-fly dynamic.
+ */
+
+let onReplayReady
+const sessionReplayInitialized = new Promise(resolve => onReplayReady = resolve)
+
+export const sharedChannel = Object.freeze({
+  onReplayReady,
+  sessionReplayInitialized
+})

src/common/harvest/harvest-scheduler.js

@@ -8,6 +8,7 @@ import { SharedContext } from '../context/shared-context'
 import { Harvest, getSubmitMethod } from './harvest'
 import { subscribeToEOL } from '../unload/eol'
 import { getConfigurationValue } from '../config/config'
+import { SESSION_EVENTS } from '../session/session-entity'
 
 /**
  * Periodically invokes harvest calls and handles retries
@@ -37,10 +38,16 @@ export class HarvestScheduler extends SharedContext {
     // unload if EOL mechanism fires
     subscribeToEOL(this.unload.bind(this), getConfigurationValue(this.sharedContext.agentIdentifier, 'allow_bfcache')) // TO DO: remove feature flag after rls stable
 
-    // unload if session resets
-    this.sharedContext?.ee.on('session-reset', this.unload.bind(this))
+    /* Flush all buffered data if session resets and give up retries. This should be synchronous to ensure that the correct `session` value is sent.
+      Since session-reset generates a new session ID and the ID is grabbed at send-time, any delays or retries would cause the payload to be sent under
+      the wrong session ID. */
+    this.sharedContext?.ee.on(SESSION_EVENTS.RESET, () => this.runHarvest({ forceNoRetry: true }))
   }
 
+  /**
+   * This function is only meant for the last outgoing harvest cycle of a page. It trickles down to using sendBeacon, which should not be used
+   * to send payloads while the page is still active, due to limitations on how much data can be buffered in the API at any one time.
+   */
   unload () {
     if (this.aborted) return
     // If opts.onUnload is defined, these are special actions to execute before attempting to send the final payload.
@@ -118,7 +125,7 @@ export class HarvestScheduler extends SharedContext {
         payload,
         opts,
         submitMethod,
-        cbFinished: onHarvestFinished,
+        cbFinished: cbRanAfterSend,
         customUrl: this.opts.customUrl,
         raw: this.opts.raw
       })
@@ -129,9 +136,13 @@ export class HarvestScheduler extends SharedContext {
     }
     return
 
-    function onHarvestFinished (result) {
-      if (result.blocked) scheduler.onHarvestBlocked(opts, result)
-      else scheduler.onHarvestFinished(opts, result)
+    /**
+     * This is executed immediately after harvest sends the data via XHR, or if there's nothing to send. Note that this excludes on unloading / sendBeacon.
+     * @param {Object} result
+     */
+    function cbRanAfterSend (result) {
+      if (opts?.forceNoRetry) result.retry = false // discard unsent data rather than re-queuing for next harvest attempt
+      scheduler.onHarvestFinished(opts, result)
     }
   }
 

src/common/session/session-entity.js

@@ -5,26 +5,29 @@ import { ee } from '../event-emitter/contextual-ee'
 import { Timer } from '../timer/timer'
 import { isBrowserScope } from '../util/global-scope'
 import { DEFAULT_EXPIRES_MS, DEFAULT_INACTIVE_MS, PREFIX } from './constants'
-import { LocalMemory } from '../storage/local-memory'
 import { InteractionTimer } from '../timer/interaction-timer'
 import { wrapEvents } from '../wrap'
 import { getModeledObject } from '../config/state/configurable'
 import { handle } from '../event-emitter/handle'
 import { SUPPORTABILITY_METRIC_CHANNEL } from '../../features/metrics/constants'
 import { FEATURE_NAMES } from '../../loaders/features/features'
 
+export const MODE = {
+  OFF: 0,
+  FULL: 1,
+  ERROR: 2
+}
 // this is what can be stored in local storage (not enforced but probably should be)
 // these values should sync between local storage and the parent class props
 const model = {
   value: '',
   inactiveAt: 0,
   expiresAt: 0,
   updatedAt: Date.now(),
-  sessionReplay: 0,
-  sessionTraceActive: false,
+  sessionReplay: MODE.OFF,
+  sessionTraceMode: MODE.OFF,
   custom: {}
 }
-
 export const SESSION_EVENTS = {
   PAUSE: 'session-pause',
   RESET: 'session-reset',
@@ -42,16 +45,16 @@ export class SessionEntity {
     this.setup(opts)
   }
 
-  setup ({ agentIdentifier, key, value = generateRandomHexString(16), expiresMs = DEFAULT_EXPIRES_MS, inactiveMs = DEFAULT_INACTIVE_MS, storageAPI = new LocalMemory() }) {
-    if (!agentIdentifier || !key) throw new Error('Missing Required Fields')
-    if (!isBrowserScope) this.storage = new LocalMemory()
-    else this.storage = storageAPI
-
+  setup ({ agentIdentifier, key, storage, value = generateRandomHexString(16), expiresMs = DEFAULT_EXPIRES_MS, inactiveMs = DEFAULT_INACTIVE_MS }) {
+    if (!agentIdentifier || !key || !storage) {
+      throw new Error(`Missing required field(s):${!agentIdentifier ? ' agentID' : ''}${!key ? ' key' : ''}${!storage ? ' storage' : ''}`)
+    }
+    this.agentIdentifier = agentIdentifier
+    this.storage = storage
     this.state = {}
 
     this.sync(model)
 
-    this.agentIdentifier = agentIdentifier
     // key is intended to act as the k=v pair
     this.key = key
     // value is intended to act as the primary value of the k=v pair
@@ -207,7 +210,7 @@ export class SessionEntity {
       this.setup({
         agentIdentifier: this.agentIdentifier,
         key: this.key,
-        storageAPI: this.storage,
+        storage: this.storage,
         expiresMs: this.expiresMs,
         inactiveMs: this.inactiveMs
       })