add b3 header for trace propagation on initial webhook

lib/middleware.js

@@ -228,7 +228,6 @@ module.exports = function(srf, logger) {
     const {rootSpan, application:app} = req.locals;
     let span;
     try {
-
       if (app.tasks) {
         app.tasks = normalizeJambones(logger, app.tasks).map((tdata) => makeTask(logger, tdata));
         if (0 === app.tasks.length) throw new Error('no application provided');
@@ -239,7 +238,10 @@ module.exports = function(srf, logger) {
         req.locals.callInfo);
       const obj = rootSpan.startChildSpan('performAppWebhook');
       span = obj.span;
-      const json = await app.requestor.request('session:new', app.call_hook, params);
+      const b3 = rootSpan.getTracingPropagation();
+      const httpHeaders = b3 && {b3};
+      console.log(httpHeaders);
+      const json = await app.requestor.request('session:new', app.call_hook, params, httpHeaders);
       app.tasks = normalizeJambones(logger, json).map((tdata) => makeTask(logger, tdata));
       span.setAttributes({
         'http.statusCode': 200,

lib/tasks/task.js

@@ -90,6 +90,13 @@ class Task extends Emitter {
     return {span, ctx};
   }
 
+  getTracingPropagation(encoding) {
+    // TODO: support encodings beyond b3 https://github.com/openzipkin/b3-propagation
+    if (this.span) {
+      return `${this.span.spanContext().traceId}-${this.span.spanContext().spanId}-1`;
+    }
+  }
+
   /**
    * when a subclass Task has completed its work, it should call this method
    */

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);