Milo: Use custom config caching layer

milo/appengine/frontend/config.go

 // Copyright 2015 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package frontend
 
 import (
         "net/http"
 
+        "cloud.google.com/go/datastore"
+
         "github.com/luci/luci-go/common/logging"
         "github.com/luci/luci-go/milo/appengine/common"
         "github.com/luci/luci-go/server/router"
         "github.com/luci/luci-go/server/templates"
 )
 
 // ConfigsHandler renders the page showing the currently loaded set of luci-configs.
 func ConfigsHandler(c *router.Context) {
         projects, err := common.GetAllProjects(c.Context)
         if err != nil {
                 common.ErrorPage(
                         c, http.StatusInternalServerError,
                         "Error while getting projects: "+err.Error())
                 return
         }
+        sc, err := common.GetCurrentServiceConfig(c.Context)
+        if err != nil && err != datastore.ErrNoSuchEntity {
+                common.ErrorPage(
+                        c, http.StatusInternalServerError,
+                        "Error while getting service config: "+err.Error())
+                return
+        }
 
-        templates.MustRender(c.Context, c.Writer, "pages/config.html", templates.Args{
-                "Projects": projects,
+        templates.MustRender(c.Context, c.Writer, "pages/configs.html", templates.Args{
+                "Projects":      projects,
+                "ServiceConfig": sc,
         })
 }
 
 // UpdateHandler is an HTTP handler that handles configuration update requests.
-// TODO(hinoka): Migrate to cfgclient and remove this.
 func UpdateConfigHandler(ctx *router.Context) {
         c, h := ctx.Context, ctx.Writer
-        err := common.UpdateProjectConfigs(c)
-        if err != nil {
-                logging.WithError(err).Errorf(c, "Update Handler encountered error")
-                h.WriteHeader(500)
+        projErr := common.UpdateProjectConfigs(c)
+        if projErr != nil {
+                logging.WithError(projErr).Errorf(c, "project update handler encountered error")
+        }
+        servErr := common.UpdateServiceConfig(c)
+        if servErr != nil {
+                logging.WithError(servErr).Errorf(c, "service update handler encountered error")
+        }
+        if projErr != nil || servErr != nil {
+                h.WriteHeader(http.StatusInternalServerError)
                 return
         }
-        logging.Infof(c, "Successfully completed")
-        h.WriteHeader(200)
+        h.WriteHeader(http.StatusOK)
 }