modulesLoadedBeforeTrace check incorrect

Regex now supports npm org modules, e.g. @google/cloud-trace instead of
@google - see https://regex101.com/r/lW2bE3/4 for examples.

filesLoadedBeforeTrace now ignores @google/cloud-trace instead of
@google

Also fixed double spacing.

Stops the warning:
```
WARN :@google/cloud-trace: Tracing might not work as the following modules  were loaded before the trace agent was initialized: ["@google"]
```

index.js

@@ -27,15 +27,15 @@ var common = require('@google/cloud-diagnostics-common');
 var semver = require('semver');
 var constants = require('./lib/constants.js');
 var path = require('path');
+var util = require('./lib/util.js');
 
 var modulesLoadedBeforeTrace = [];
-var moduleRegex =
-  new RegExp('.*?node_modules\\' + path.sep + '([^\\' + path.sep + ']*).*');
+
 for (var i = 0; i < filesLoadedBeforeTrace.length; i++) {
-  var matches = moduleRegex.exec(filesLoadedBeforeTrace[i]);
-  if (matches && matches.length > 1 &&
-      modulesLoadedBeforeTrace.indexOf(matches[1]) === -1) {
-    modulesLoadedBeforeTrace.push(matches[1]);
+  var moduleName = util.packageNameFromPath(filesLoadedBeforeTrace[i]);
+  if (moduleName && moduleName !== '@google/cloud-trace' &&
+      modulesLoadedBeforeTrace.indexOf(moduleName) === -1) {
+    modulesLoadedBeforeTrace.push(moduleName);
   }
 }
 
@@ -146,7 +146,7 @@ var publicAgent = {
 
     if (modulesLoadedBeforeTrace.length > 0) {
       logger.warn('Tracing might not work as the following modules ' +
-        ' were loaded before the trace agent was initialized: ' +
+        'were loaded before the trace agent was initialized: ' +
         JSON.stringify(modulesLoadedBeforeTrace));
     }
 

lib/util.js

@@ -16,6 +16,8 @@
 
 'use strict';
 
+var path = require('path');
+
 /**
  * Produces an object summarization of limited size. This summarization
  * does not adhere to the JSON spec so it cannot be reparsed even if
@@ -63,6 +65,31 @@ function stringifyPrefix(o, n) {
   return buf.toString('utf8', 0, pos);
 }
 
+// Includes support for npm '@org/name' packages
+// Regex: .*?node_modules\/(@[^\/]*\/[^\/]*|[^\/]*).*
+// Tests: https://regex101.com/r/lW2bE3/4
+var moduleRegex = new RegExp(
+  '.*?node_modules' + path.sep +
+  '(@[^' + path.sep +
+  ']*' + path.sep +
+  '[^' + path.sep +
+  ']*|[^' + path.sep +
+  ']*).*'
+);
+
+/**
+ * Retrieves a package name from the full import path.
+ * For example:
+ *   './node_modules/bar/index/foo.js' => 'bar'
+ *
+ * @param {string} path The full import path.
+ */
+function packageNameFromPath(path) {
+  var matches = moduleRegex.exec(path);
+  return matches && matches.length > 1 ? matches[1] : null;
+}
+
 module.exports = {
-  stringifyPrefix: stringifyPrefix
+  stringifyPrefix: stringifyPrefix,
+  packageNameFromPath: packageNameFromPath
 };

test/test-util.js

@@ -44,3 +44,16 @@ describe('util.stringifyPrefix', function() {
   });
 });
 
+describe('util.packageNameFromPath', function() {
+  it('should work for standard packages', function() {
+    var path = './appengine-sails/node_modules/testmodule/index.js';
+    assert.equal(util.packageNameFromPath(path),
+      'testmodule');
+  });
+
+  it('should work for namespaced packages', function() {
+    var path = './appengine-sails/node_modules/@google/cloud-trace/index.js';
+    assert.equal(util.packageNameFromPath(path),
+      '@google/cloud-trace');
+  });
+});