Feature/trace propagation (#96)

* add b3 header for trace propagation on initial webhook

* logging

* add tracing context to all webhooks

* Add span parameter to Task.getTracingPropagation. Pass proper span to getTracingPropagation calls in Task methods to propagate the proper spanId (#91)

* some tracing cleanup

* bugfix: azure stt results need to be ordered by confidence level before processing (#92)

* fix assertion

* bugfix: vad was not enabled on config verb, restart STT on empty transcript in gather

* gather: dont send webhook if call is gone

* rest outdial: handle 302 redirect so we can later cancel request if needed (#95)

* gather: restart if we get an empty transcript (looking at you, Azure)

Co-authored-by: javibookline <98887695+javibookline@users.noreply.github.com>

lib/tasks/say.js

@@ -44,7 +44,6 @@ class TaskSay extends Task {
 
     this.logger.info({vendor, language, voice}, 'TaskSay:exec');
     this.ep = ep;
-    let span;
     try {
       if (!credentials) {
         writeAlerts({
@@ -58,11 +57,12 @@ class TaskSay extends Task {
       let lastUpdated = false;
 
       /* otel: trace time for tts */
-      span = this.startSpan('tts-generation', {
+      const {span} = this.startChildSpan('tts-generation', {
         'tts.vendor': vendor,
         'tts.language': language,
         'tts.voice': voice
       });
+      this.ttsSpan = span;
 
       const filepath = (await Promise.all(this.text.map(async(text) => {
         if (this.killed) return;
@@ -91,10 +91,10 @@ class TaskSay extends Task {
           updateSpeechCredentialLastUsed(credentials.speech_credential_sid)
             .catch(() => {/*already logged error */});
         }
-        span.setAttributes({'tts.cached': servedFromCache});
+        this.ttsSpan.setAttributes({'tts.cached': servedFromCache});
         return filePath;
       }))).filter((fp) => fp && fp.length);
-      span?.end();
+      this.ttsSpan?.end();
       this.logger.debug({filepath}, 'synthesized files for tts');
 
       while (!this.killed && (this.loop === 'forever' || this.loop--) && this.ep?.connected) {
@@ -112,7 +112,7 @@ class TaskSay extends Task {
         } while (!this.killed && ++segment < filepath.length);
       }
     } catch (err) {
-      span?.end();
+      this.ttsSpan?.end();
       this.logger.info(err, 'TaskSay:exec error');
     }
     this.emit('playDone');