add b3 header for trace propagation on initial webhook

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);
   }

lib/utils/http-requestor.js

@@ -49,7 +49,7 @@ class HttpRequestor extends BaseRequestor {
    * @param {string} [hook.password] - if basic auth is protecting the endpoint
    * @param {object} [params] - request parameters
    */
-  async request(type, hook, params) {
+  async request(type, hook, params, httpHeaders = {}) {
     assert(HookMsgTypes.includes(type));
     const payload = params ? snakeCaseKeys(params, ['customerData', 'sip']) : null;
     const url = hook.url || hook;
@@ -64,8 +64,8 @@ class HttpRequestor extends BaseRequestor {
     let buf;
     try {
       const sigHeader = this._generateSigHeader(payload, this.secret);
-      const headers = {...sigHeader, ...this.authHeader};
-      //this.logger.info({url, headers}, 'send webhook');
+      const headers = {...sigHeader, ...this.authHeader, ...httpHeaders};
+      this.logger.debug({url, headers}, 'send webhook');
       buf = this._isRelativeUrl(url) ?
         await this.post(url, payload, headers) :
         await bent(method, 'buffer', 200, 201, 202)(url, payload, headers);