HTTP trigger set

This is currently:
 1. A list of http triggers
 2. A method to generate a mux router from that list

This will be in the future:
 1. A way to keep the set of triggers up to date, by watching the controller API
 2. A way to update the router when the trigger set changes

src/router/httpTriggers.go

@@ -0,0 +1,62 @@
+/*
+Copyright 2016 The Fission Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package router
+
+import (
+	"github.com/gorilla/mux"
+)
+
+type HTTPTriggerSet struct {
+	*functionServiceMap
+	*mutableRouter
+	controllerUrl  string
+	poolManagerUrl string
+	triggers       []httptrigger
+}
+
+func makeHTTPTriggerSet(fmap *functionServiceMap, controllerUrl string, poolManagerUrl string) *HTTPTriggerSet {
+	triggers := make([]httptrigger, 1)
+	return &HTTPTriggerSet{
+		functionServiceMap: fmap,
+		triggers:           triggers,
+		controllerUrl:      controllerUrl,
+		poolManagerUrl:     poolManagerUrl,
+	}
+}
+
+func (triggers *HTTPTriggerSet) subscribeRouter(mr *mutableRouter) {
+	triggers.mutableRouter = mr
+	mr.updateRouter(triggers.getRouterFromTriggers())
+	go triggers.watchTriggers()
+}
+
+func (triggers *HTTPTriggerSet) getRouterFromTriggers() *mux.Router {
+	muxRouter := mux.NewRouter()
+	for _, trigger := range triggers.triggers {
+		fh := &functionHandler{
+			fmap:           triggers.functionServiceMap,
+			function:       trigger.function,
+			poolManagerUrl: triggers.poolManagerUrl,
+		}
+		muxRouter.HandleFunc(trigger.urlPattern, fh.handler)
+	}
+	return muxRouter
+}
+
+func (triggers *HTTPTriggerSet) watchTriggers() {
+	// watch controller for updates to triggers and update the router accordingly
+}