fix(agent): check for the newrelic agent, if present ask the user to require Trace before that

Author: gergelyke

lib/index.js

@@ -15,6 +15,12 @@ function Trace () {
     return
   }
 
+  // warn the user if the newrelic agent is present as well
+  if (require.cache.__NR_cache) {
+    console.error('Make sure to require Trace before New Relic, otherwise Trace won\'t start')
+    return
+  }
+
   this.agent = Agent.create({
     config: this.config
   })

lib/utils/shimmer.js

@@ -40,6 +40,10 @@ function wrap (nodule, noduleName, methods, wrapper) {
       return debug('%s already wrapped by agent.', fqmn)
     }
 
+    if (original.__NR_original) {
+      return debug('%s already wrapped the newrelic agent, so it is wrapped by us as well', fqmn)
+    }
+
     var wrapped = wrapper(original, method)
     wrapped.__RS_original = original
     wrapped.__RS_unwrap = function __RS_unwrap () {