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/utils/call-tracer.js

@@ -44,6 +44,21 @@ class RootSpan {
     return this._span.spanContext().traceId;
   }
 
+  get spanId() {
+    return this._span.spanContext().spanId;
+  }
+
+  get traceFlags() {
+    return this._span.spanContext().traceFlags;
+  }
+
+  getTracingPropagation(encoding) {
+    // TODO: support encodings beyond b3 https://github.com/openzipkin/b3-propagation
+    if (this._span  && this.traceId !== '00000000000000000000000000000000') {
+      return `${this.traceId}-${this.spanId}-1`;
+    }
+  }
+
   setAttributes(attrs) {
     this._span.setAttributes(attrs);
   }