fix requests to the agent being traced (#1274)

Author: rochdev

packages/dd-trace/src/opentracing/tracer.js

@@ -56,23 +56,6 @@ class DatadogTracer extends Tracer {
     }
   }
 
-  startSpan (name, fields) {
-    if (fields) {
-      if (fields.references) {
-        return super.startSpan(name, fields)
-      } else if (fields.childOf) {
-        let parent = fields.childOf
-        if (parent instanceof Span) {
-          parent = parent.context()
-        }
-        if (parent instanceof SpanContext) {
-          return this._startSpanInternal(name, fields, parent, REFERENCE_CHILD_OF)
-        }
-      }
-    }
-    return this._startSpanInternal(name, fields, null, null)
-  }
-
   _startSpan (name, fields) {
     const reference = getParent(fields.references)
     const type = reference && reference.type()

packages/dd-trace/src/scope/async_resource.js

@@ -3,10 +3,16 @@
 const { createHook, executionAsyncResource } = require('async_hooks')
 const Base = require('./base')
 
+let singleton = null
+
 class Scope extends Base {
   constructor (config) {
+    if (singleton) return singleton
+
     super()
 
+    singleton = this
+
     this._ddResourceStore = Symbol('ddResourceStore')
     this._config = config
     this._stack = []

packages/dd-trace/test/opentracing/tracer.spec.js

@@ -3,6 +3,7 @@
 const opentracing = require('opentracing')
 const os = require('os')
 const SpanContext = require('../../src/opentracing/span_context')
+const NoopSpan = require('../../src/noop/span')
 const Reference = opentracing.Reference
 
 describe('Tracer', () => {
@@ -297,13 +298,9 @@ describe('Tracer', () => {
     it('should return the same instance when the parent is a noop', () => {
       tracer = new Tracer(config)
 
-      sampler.isSampled.returns(false)
-      const parent = tracer.startSpan('parent', fields)
-      sampler.isSampled.returns(true)
+      const parent = new NoopSpan(tracer)
 
-      fields.references = [
-        new Reference(opentracing.REFERENCE_CHILD_OF, parent)
-      ]
+      fields.childOf = parent
 
       span = tracer.startSpan('name', fields)
 

packages/dd-trace/test/plugins/util/redis.spec.js

@@ -1,5 +1,7 @@
 'use strict'
 
+wrapIt()
+
 describe('plugins/util/redis', () => {
   let redis
   let tracer

packages/dd-trace/test/scope/async_resource.spec.js

@@ -27,10 +27,6 @@ function test () {
     span = new Span()
   })
 
-  afterEach(() => {
-    scope.disable()
-  })
-
   it('should not break propagation for nested resources', () => {
     scope.activate(span, () => {
       const asyncResource = new AsyncResource(