Support ASR TTS fallback (#713)

* asr/tts fallback

* add notification

* add notification

* wip

* wip

* wip

* wip

* wip

* wip

* wip

* wip

lib/session/call-session.js

@@ -188,6 +188,24 @@ class CallSession extends Emitter {
     this._synthesizer = synth;
   }
 
+  /**
+   * ASR TTS fallback
+   */
+  get hasFallbackAsr() {
+    return this._hasFallbackAsr || false;
+  }
+
+  set hasFallbackAsr(i) {
+    this._hasFallbackAsr = i;
+  }
+
+  get hasFallbackTts() {
+    return this._hasFallbackTts || false;
+  }
+
+  set hasFallbackTts(i) {
+    this._hasFallbackTts = i;
+  }
   /**
    * default vendor to use for speech synthesis if not provided in the app
    */
@@ -1832,6 +1850,7 @@ Duration=${duration} `
   /**
    * called when the caller has hung up.  Provided for subclasses to override
    * in order to apply logic at this point if needed.
+   * return true if success fallback, return false if not
    */
   _callerHungup() {
     assert(false, 'subclass responsibility to override this method');

lib/tasks/gather.js

@@ -174,12 +174,7 @@ class TaskGather extends SttTask {
           this._startTranscribing(ep);
           return updateSpeechCredentialLastUsed(this.sttCredentials.speech_credential_sid);
         } catch (e) {
-          if (this.fallbackVendor && this.isHandledByPrimaryProvider) {
+          await this._startFallback(cs, ep, {error: e});
-            await this._fallback();
-            startListening(cs, ep);
-          } else {
-            this.logger.error({error: e}, 'error in initSpeech');
-          }
         }
       }
     };
@@ -906,9 +901,9 @@ class TaskGather extends SttTask {
   _onTranscriptionComplete(cs, ep) {
     this.logger.debug('TaskGather:_onTranscriptionComplete');
   }
-  async _onJambonzError(cs, ep, evt) {
+
-    this.logger.info({evt}, 'TaskGather:_onJambonzError');
+  async _startFallback(cs, ep, evt) {
-    if (this.isHandledByPrimaryProvider && this.fallbackVendor) {
+    if (this.canFallback) {
       ep.stopTranscription({
         vendor: this.vendor,
         bugname: this.bugname
@@ -916,17 +911,31 @@ class TaskGather extends SttTask {
         .catch((err) => this.logger.error({err}, `Error stopping transcription for primary vendor ${this.vendor}`));
       const {updateSpeechCredentialLastUsed} = require('../utils/db-utils')(this.logger, cs.srf);
       try {
-        await this._fallback();
+        this.logger.debug('gather:_startFallback');
-        await this._initSpeech(cs, ep);
+        this.notifyError({ msg: 'ASR error',
+          details:`STT Vendor ${this.vendor} error: ${evt.error || evt.reason}`, failover: 'in progress'});
+        await this._initFallback();
+        this._speechHandlersSet = false;
+        await this._setSpeechHandlers(cs, ep);
         this._startTranscribing(ep);
         updateSpeechCredentialLastUsed(this.sttCredentials.speech_credential_sid);
-        return;
+        return true;
       } catch (error) {
         this.logger.info({error}, `There is error while falling back to ${this.fallbackVendor}`);
+        this.notifyError({ msg: 'ASR error',
+          details:`STT Vendor ${this.vendor} error: ${evt.error || evt.reason}`, failover: 'not available'});
       }
+    } else {
+      this.logger.debug('gather:_startFallback no condition for falling back');
+      this.notifyError({ msg: 'ASR error',
+        details:`STT Vendor ${this.vendor} error: ${evt.error || evt.reason}`, failover: 'not available'});
+    }
+    return false;
   }
-    const {writeAlerts, AlertType} = cs.srf.locals;
 
+  async _onJambonzError(cs, ep, evt) {
+    this.logger.info({evt}, 'TaskGather:_onJambonzError');
+    const {writeAlerts, AlertType} = cs.srf.locals;
     if (this.vendor === 'nuance') {
       const {code, error} = evt;
       if (code === 404 && error === 'No speech') return this._resolve('timeout');
@@ -939,18 +948,24 @@ class TaskGather extends SttTask {
       message: `Custom speech vendor ${this.vendor} error: ${evt.error}`,
       vendor: this.vendor,
     }).catch((err) => this.logger.info({err}, 'Error generating alert for jambonz custom connection failure'));
-    this.notifyError({msg: 'ASR error', details:`Custom speech vendor ${this.vendor} error: ${evt.error}`});
+    if (!(await this._startFallback(cs, ep, evt))) {
-  }
-
-  _onVendorConnectFailure(cs, _ep, evt) {
-    super._onVendorConnectFailure(cs, _ep, evt);
       this.notifyTaskDone();
     }
+  }
 
-  _onVendorError(cs, _ep, evt) {
+  async _onVendorConnectFailure(cs, _ep, evt) {
+    super._onVendorConnectFailure(cs, _ep, evt);
+    if (!(await this._startFallback(cs, _ep, evt))) {
+      this.notifyTaskDone();
+    }
+  }
+
+  async _onVendorError(cs, _ep, evt) {
     super._onVendorError(cs, _ep, evt);
+    if (!(await this._startFallback(cs, _ep, evt))) {
       this._resolve('stt-error', evt);
     }
+  }
 
   _onVadDetected(cs, ep) {
     if (this.bargein && this.minBargeinWordCount === 0) {

lib/tasks/say.js

@@ -117,10 +117,6 @@ class TaskSay extends Task {
           alert_type: AlertType.TTS_NOT_PROVISIONED,
           vendor
         }).catch((err) => this.logger.info({err}, 'Error generating alert for no tts'));
-        this.notifyError({
-          msg: 'TTS error',
-          details:`No speech credentials provisioned for selected vendor ${vendor}`
-        });
         throw new Error('no provisioned speech credentials for TTS');
       }
       // synthesize all of the text elements
@@ -192,7 +188,6 @@ class TaskSay extends Task {
             vendor,
             detail: err.message
           }).catch((err) => this.logger.info({err}, 'Error generating alert for tts failure'));
-          this.notifyError({msg: 'TTS error', details: err.message || err});
           throw err;
         }
       };
@@ -215,16 +210,16 @@ class TaskSay extends Task {
     await super.exec(cs);
     this.ep = ep;
 
-    const vendor = this.synthesizer.vendor && this.synthesizer.vendor !== 'default' ?
+    let vendor = this.synthesizer.vendor && this.synthesizer.vendor !== 'default' ?
       this.synthesizer.vendor :
       cs.speechSynthesisVendor;
-    const language = this.synthesizer.language && this.synthesizer.language !== 'default' ?
+    let language = this.synthesizer.language && this.synthesizer.language !== 'default' ?
       this.synthesizer.language :
       cs.speechSynthesisLanguage ;
-    const voice =  this.synthesizer.voice && this.synthesizer.voice !== 'default' ?
+    let voice =  this.synthesizer.voice && this.synthesizer.voice !== 'default' ?
       this.synthesizer.voice :
       cs.speechSynthesisVoice;
-    const label = this.synthesizer.label && this.synthesizer.label !== 'default' ?
+    let label = this.synthesizer.label && this.synthesizer.label !== 'default' ?
       this.synthesizer.label :
       cs.speechSynthesisLabel;
 
@@ -241,12 +236,22 @@ class TaskSay extends Task {
       this.synthesizer.fallbackLabel :
       cs.fallbackSpeechSynthesisLabel;
 
+    if (cs.hasFallbackTts) {
+      vendor = fallbackVendor;
+      language = fallbackLanguage;
+      voice = fallbackVoice;
+      label = fallbackLabel;
+    }
+
     let filepath;
     try {
       filepath = await this._synthesizeWithSpecificVendor(cs, ep, {vendor, language, voice, label});
     } catch (error) {
-      if (fallbackVendor && this.isHandledByPrimaryProvider) {
+      if (fallbackVendor && this.isHandledByPrimaryProvider && !cs.hasFallbackTts) {
+        this.notifyError(
+          { msg: 'TTS error', details:`TTS vendor ${vendor} error: ${error}`, failover: 'in progress'});
         this.isHandledByPrimaryProvider = false;
+        cs.hasFallbackTts = true;
         this.logger.info(`Synthesize error, fallback to ${fallbackVendor}`);
         filepath = await this._synthesizeWithSpecificVendor(cs, ep,
           {
@@ -256,6 +261,8 @@ class TaskSay extends Task {
             label: fallbackLabel
           });
       } else {
+        this.notifyError(
+          { msg: 'TTS error', details:`TTS vendor ${vendor} error: ${error}`, failover: 'not available'});
         throw error;
       }
     }

lib/tasks/stt-task.js

@@ -102,6 +102,13 @@ class SttTask extends Task {
       this.fallbackLabel = cs.fallbackSpeechRecognizerLabel;
       if (this.data.recognizer) this.data.recognizer.fallbackLabel = this.fallbackLabel;
     }
+    // If call is already fallback to 2nd ASR vendor
+    // use that.
+    if (cs.hasFallbackAsr) {
+      this.vendor = this.fallbackVendor;
+      this.language = this.fallbackLanguage;
+      this.label = this.fallbackLabel;
+    }
     if (!this.data.recognizer.vendor) {
       this.data.recognizer.vendor = this.vendor;
     }
@@ -119,9 +126,11 @@ class SttTask extends Task {
       try {
         this.sttCredentials = await this._initSpeechCredentials(this.cs, this.vendor, this.label);
       } catch (error) {
-        if (this.fallbackVendor && this.isHandledByPrimaryProvider) {
+        if (this.canFallback) {
-          await this._fallback();
+          await this._initFallback();
+          this.notifyError({ msg: 'ASR error', details:`Invalid vendor ${this.vendor}`, failover: 'in progress'});
         } else {
+          this.notifyError({ msg: 'ASR error', details:`Invalid vendor ${this.vendor}`, failover: 'not available'});
           throw error;
         }
       }
@@ -190,9 +199,14 @@ class SttTask extends Task {
     return credentials;
   }
 
-  async _fallback() {
+  get canFallback() {
+    return this.fallbackVendor && this.isHandledByPrimaryProvider && !this.cs.hasFallbackAsr;
+  }
+
+  async _initFallback() {
     assert(this.fallbackVendor, 'fallback failed without fallbackVendor configuration');
     this.isHandledByPrimaryProvider = false;
+    this.cs.hasFallbackAsr = true;
     this.logger.info(`Failed to use primary STT provider, fallback to ${this.fallbackVendor}`);
     this.vendor = this.fallbackVendor;
     this.language = this.fallbackLanguage;
@@ -201,6 +215,8 @@ class SttTask extends Task {
     this.data.recognizer.language = this.language;
     this.data.recognizer.label = this.label;
     this.sttCredentials = await this._initSpeechCredentials(this.cs, this.vendor, this.label);
+    // cleanup previous listener from previous vendor
+    this.removeCustomEventListeners();
   }
 
   async compileHintsForCobalt(ep, hostport, model, token, hints) {
@@ -263,7 +279,6 @@ class SttTask extends Task {
       detail: evt.error,
       vendor: this.vendor,
     }).catch((err) => this.logger.info({err}, `Error generating alert for ${this.vendor} connection failure`));
-    this.notifyError({msg: 'ASR error', details:`Failed connecting to speech vendor ${this.vendor}: ${evt.error}`});
   }
 
   _onVendorConnectFailure(cs, _ep, evt) {
@@ -276,7 +291,6 @@ class SttTask extends Task {
       message: `Failed connecting to ${this.vendor} speech recognizer: ${reason}`,
       vendor: this.vendor,
     }).catch((err) => this.logger.info({err}, `Error generating alert for ${this.vendor} connection failure`));
-    this.notifyError({msg: 'ASR error', details:`Failed connecting to speech vendor ${this.vendor}: ${reason}`});
   }
 }
 

lib/tasks/transcribe.js

@@ -80,12 +80,15 @@ class TaskTranscribe extends SttTask {
 
       updateSpeechCredentialLastUsed(this.sttCredentials.speech_credential_sid)
         .catch(() => {/*already logged error */});
-
-      await this.awaitTaskDone();
     } catch (err) {
+      if (!(await this._startFallback(cs, ep, {error: err}))) {
         this.logger.info(err, 'TaskTranscribe:exec - error');
         this.parentTask && this.parentTask.emit('error', err);
+        this.removeCustomEventListeners();
+        return;
       }
+    }
+    await this.awaitTaskDone();
     this.removeCustomEventListeners();
   }
 
@@ -512,10 +515,8 @@ class TaskTranscribe extends SttTask {
     }
   }
 
-  async _onJambonzError(cs, _ep, evt) {
+  async _startFallback(cs, _ep, evt) {
-    this.logger.info({evt}, 'TaskTranscribe:_onJambonzError');
+    if (this.canFallback) {
-    if (this.paused) return;
-    if (this.isHandledByPrimaryProvider && this.fallbackVendor) {
       _ep.stopTranscription({
         vendor: this.vendor,
         bugname: this.bugname
@@ -523,18 +524,33 @@ class TaskTranscribe extends SttTask {
         .catch((err) => this.logger.error({err}, `Error stopping transcription for primary vendor ${this.vendor}`));
       const {updateSpeechCredentialLastUsed} = require('../utils/db-utils')(this.logger, cs.srf);
       try {
-        await this._fallback();
+        this.notifyError({ msg: 'ASR error',
+          details:`STT Vendor ${this.vendor} error: ${evt.error || evt.reason}`, failover: 'in progress'});
+        await this._initFallback();
         let channel = 1;
         if (this.ep !== _ep) {
           channel = 2;
         }
+        this[`_speechHandlersSet_${channel}`] = false;
         this._startTranscribing(cs, _ep, channel);
         updateSpeechCredentialLastUsed(this.sttCredentials.speech_credential_sid);
-        return;
+        return true;
       } catch (error) {
+        this.notifyError({ msg: 'ASR error',
+          details:`STT Vendor ${this.vendor} error: ${evt.error || evt.reason}`, failover: 'not available'});
         this.logger.info({error}, `There is error while falling back to ${this.fallbackVendor}`);
       }
     } else {
+      this.logger.debug('transcribe:_startFallback no condition for falling back');
+      this.notifyError({ msg: 'ASR error',
+        details:`STT Vendor ${this.vendor} error: ${evt.error || evt.reason}`, failover: 'not available'});
+    }
+    return false;
+  }
+
+  async _onJambonzError(cs, _ep, evt) {
+    this.logger.info({evt}, 'TaskTranscribe:_onJambonzError');
+    if (this.paused) return;
     const {writeAlerts, AlertType} = cs.srf.locals;
 
     if (this.vendor === 'nuance') {
@@ -549,11 +565,12 @@ class TaskTranscribe extends SttTask {
       message: `Custom speech vendor ${this.vendor} error: ${evt.error}`,
       vendor: this.vendor,
     }).catch((err) => this.logger.info({err}, 'Error generating alert for jambonz custom connection failure'));
-      this.notifyError({msg: 'ASR error', details:`Custom speech vendor ${this.vendor} error: ${evt.error}`});
+    if (!(await this._startFallback(cs, _ep, evt))) {
+      this.notifyTaskDone();
     }
   }
 
-  _onVendorConnectFailure(cs, _ep, channel, evt) {
+  async _onVendorConnectFailure(cs, _ep, channel, evt) {
     super._onVendorConnectFailure(cs, _ep, evt);
     if (this.childSpan[channel - 1] && this.childSpan[channel - 1].span) {
       this.childSpan[channel - 1].span.setAttributes({
@@ -562,8 +579,10 @@ class TaskTranscribe extends SttTask {
       });
       this.childSpan[channel - 1].span.end();
     }
+    if (!(await this._startFallback(cs, _ep, evt))) {
       this.notifyTaskDone();
     }
+  }
 
   _startAsrTimer(channel) {
     if (this.vendor === 'deepgram') return; // no need