Plugin API: Add createChildSpan

src/trace-plugin-interface.js

@@ -100,29 +100,6 @@ Transaction.prototype.getTraceContext = function() {
   return this.serializedTraceContext_;
 };
 
-/**
- * Runs the given function in a child span, passing it an object that
- * exposes an interface for adding labels and closing the span.
- * @param {object} options An object that specifies options for how the child
- * span is created and propogated.
- * @param {string} options.name The name to apply to the child span.
- * @param {?string} options.traceContext The serialized form of an object that
- * contains information about an existing trace context.
- * @param {?number} options.skipFrames The number of stack frames to skip when
- * collecting call stack information for the child span, starting from the top;
- * this should be set to avoid including frames in the plugin. Defaults to 0.
- * @param {function(ChildSpan)} fn A function that will be called exactly
- * once, with a ChildSpan object exposing an interface operating on the child
- * span.
- * @returns The return value of calling fn.
- */
-Transaction.prototype.runInChildSpan = function(options, fn) {
-  options = options || {};
-  var childContext = this.agent_.startSpan(options.name, {},
-    options.skipFrames ? options.skipFrames + 1 : 1);
-  return fn(new ChildSpan(this.agent_, childContext));
-};
-
 /**
  * PluginAPI constructor. Don't call directly - a plugin object will be passed to
  * plugin themselves
@@ -209,26 +186,23 @@ PluginAPI.prototype.runInRootSpan = function(options, fn) {
 
 /**
  * Convenience method which obtains a Transaction object with getTransaction()
- * and calls its runInChildSpan function on the given arguments. If there is
- * no current Transaction object, the provided function will be called with
- * null as an argument.
- * @param {object} options An object that specifies options for how the root
- * span is created and propogated. @see Transaction.prototype.runInChildSpan
- * @param {function(?Transaction)} fn A function that will be called exactly
- * once. @see Transaction.prototype.runInChildSpan
- * @returns The return value of calling fn.
+ * and creates a new child span nested within this transaction. If there is
+ * no current Transaction object, this function returns null.
+ * @param {object} options An object that specifies options for how the child
+ * span is created and propogated. @see Transaction.prototype.createChildSpan
+ * @returns A new ChildSpan object, or null if there is no active root span.
  */
-PluginAPI.prototype.runInChildSpan = function(options, fn) {
+PluginAPI.prototype.createChildSpan = function(options) {
   var transaction = this.getTransaction();
   if (transaction) {
     options = options || {};
-    var childContext = transaction.agent_.startSpan(options.name, {},
+    var childContext = this.agent_.startSpan(options.name, {},
       options.skipFrames ? options.skipFrames + 1 : 1);
-    return fn(new ChildSpan(transaction.agent_, childContext));
+    return new ChildSpan(this.agent_, childContext);
   } else {
-    this.logger_.warn(options.name + ': Attempted to run in child span ' +
+    this.logger_.warn(options.name + ': Attempted to create child span ' +
       'without root');
-    return fn(null);
+    return null;
   }
 };