support stt latency metrics (#1252)

* support stt latency metrics

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* enable stt latency calculator by config verb

* wip

* wip

* wip

* fix jslint

* fixed gather timeout does not have latency calculation

* upadte verb specification to use notifySttLatency

* move stt latency metric from call session to stt-latency calculator

* wip

lib/tasks/stt-task.js

@@ -4,6 +4,7 @@ const crypto = require('crypto');
 const { TaskPreconditions, CobaltTranscriptionEvents } = require('../utils/constants');
 const { SpeechCredentialError } = require('../utils/error');
 const {JAMBONES_AWS_TRANSCRIBE_USE_GRPC} = require('../config');
+const {TaskName} = require('../utils/constants.json');
 
 /**
  * "Please insert turns here: {{turns:4}}"
@@ -84,6 +85,9 @@ class SttTask extends Task {
     /*bug name prefix */
     this.bugname_prefix = '';
 
+    // stt latency calculator
+    this.stt_latency_ms = '';
+
   }
 
   async exec(cs, {ep, ep2}) {
@@ -91,6 +95,12 @@ class SttTask extends Task {
     this.ep = ep;
     this.ep2 = ep2;
 
+    // start vad from stt latency calculator
+    if (this.name !== TaskName.Gather ||
+      this.name === TaskName.Gather && this.needsStt) {
+      cs.startSttLatencyVad();
+    }
+
     // use session preferences if we don't have specific verb-level settings.
     if (cs.recognizer) {
       for (const k in cs.recognizer) {
@@ -400,7 +410,7 @@ class SttTask extends Task {
     dgOptions.utteranceEndMs = dgOptions.utteranceEndMs || asrTimeout;
   }
 
-  _onVendorConnect(_cs, _ep) {
+  _onVendorConnect(cs, _ep) {
     this.logger.debug(`TaskGather:_on${this.vendor}Connect`);
   }