Call options fn on each invocation in tracer.wrap (#1191)

Because the options variable in tracer.wrap was being re-assigned,
options functions were only being executing a single time, and then the
same result would be cached. This is fixed by using a variable local to
the function invocation.

Fixes #1181

packages/dd-trace/src/tracer.js

@@ -69,11 +69,12 @@ class DatadogTracer extends Tracer {
     const tracer = this
 
     return function () {
-      if (typeof options === 'function' && typeof fn === 'function') {
-        options = options.apply(this, arguments)
+      let optionsObj = options
+      if (typeof optionsObj === 'function' && typeof fn === 'function') {
+        optionsObj = optionsObj.apply(this, arguments)
       }
 
-      if (options.orphanable === false && !tracer.scope().active()) {
+      if (optionsObj.orphanable === false && !tracer.scope().active()) {
         return fn.apply(this, arguments)
       }
 
@@ -82,7 +83,7 @@ class DatadogTracer extends Tracer {
 
       if (typeof cb === 'function') {
         const scopeBoundCb = tracer.scope().bind(cb)
-        return tracer.trace(name, options, (span, done) => {
+        return tracer.trace(name, optionsObj, (span, done) => {
           arguments[lastArgId] = function (err) {
             done(err)
             return scopeBoundCb.apply(this, arguments)
@@ -91,7 +92,7 @@ class DatadogTracer extends Tracer {
           return fn.apply(this, arguments)
         })
       } else {
-        return tracer.trace(name, options, () => fn.apply(this, arguments))
+        return tracer.trace(name, optionsObj, () => fn.apply(this, arguments))
       }
     }
   }

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

@@ -383,14 +383,17 @@ describe('Tracer', () => {
       })
     })
 
-    it('should accept an options function', () => {
+    it('should accept an options function, invoked on every invocation of the wrapped function', () => {
       const it = {}
 
+      let invocations = 0
+
       function options (foo, bar) {
+        invocations++
         expect(this).to.equal(it)
         expect(foo).to.equal('hello')
         expect(bar).to.equal('goodbye')
-        return { tags: { sometag: 'somevalue' } }
+        return { tags: { sometag: 'somevalue', invocations } }
       }
 
       const fn = tracer.wrap('name', options, function () {})
@@ -400,7 +403,13 @@ describe('Tracer', () => {
       fn.call(it, 'hello', 'goodbye')
 
       expect(tracer.trace).to.have.been.calledWith('name', {
-        tags: { sometag: 'somevalue' }
+        tags: { sometag: 'somevalue', invocations: 1 }
+      })
+
+      fn.call(it, 'hello', 'goodbye')
+
+      expect(tracer.trace).to.have.been.calledWith('name', {
+        tags: { sometag: 'somevalue', invocations: 2 }
       })
     })