Milo: Use custom config caching layer

luci_config/server/cfgclient/backend/client/client.go

 // Copyright 2016 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 client implements a config client backend for a configuration client.
 package client
 
 import (
         "fmt"
         "net/http"
@@ skipping 25 matching lines @@
         Provider Provider
 }
 
 var _ backend.B = (*Backend)(nil)
 
 // ServiceURL implements backend.B.
 func (be *Backend) ServiceURL(c context.Context) url.URL { return be.Provider.GetServiceURL() }
 
 // ConfigSetURL implements backend.B.
 func (be *Backend) ConfigSetURL(c context.Context, configSet string, p backend.Params) (url.URL, error) {
-        u, err := be.getIface(c, p.Authority).GetConfigSetLocation(c, configSet)
+        u, err := be.GetConfigInterface(c, p.Authority).GetConfigSetLocation(c, configSet)
         if err != nil || u == nil {
                 return url.URL{}, err
         }
         return *u, nil
 }
 
 // Get implements backend.B.
 func (be *Backend) Get(c context.Context, configSet, path string, p backend.Params) (*backend.Item, error) {
-        svc := be.getIface(c, p.Authority)
+        svc := be.GetConfigInterface(c, p.Authority)
 
         cfg, err := svc.GetConfig(c, configSet, path, !p.Content)
         if err != nil {
                 return nil, translateConfigErr(err)
         }
 
         return makeItem(cfg), nil
 }
 
 // GetAll implements backend.B.
 func (be *Backend) GetAll(c context.Context, t backend.GetAllTarget, path string, p backend.Params) (
         []*backend.Item, error) {
 
-        svc := be.getIface(c, p.Authority)
+        svc := be.GetConfigInterface(c, p.Authority)
 
         var fn func(context.Context, string, bool) ([]config.Config, error)
         switch t {
         case backend.GetAllProject:
                 fn = svc.GetProjectConfigs
         case backend.GetAllRef:
                 fn = svc.GetRefConfigs
         default:
                 return nil, errors.Reason("unknown GetAllType: %(type)q").D("type", t).Err()
         }
 
         cfgs, err := fn(c, path, !p.Content)
         if err != nil || len(cfgs) == 0 {
                 return nil, translateConfigErr(err)
         }
 
         items := make([]*backend.Item, len(cfgs))
         for i := range cfgs {
                 items[i] = makeItem(&cfgs[i])
         }
         return items, nil
 }
 
-func (be *Backend) getIface(c context.Context, a backend.Authority) config.Interface {
+func (be *Backend) GetConfigInterface(c context.Context, a backend.Authority) config.Interface {
         return be.Provider.GetConfigClient(c, a)
 }
 
 // RemoteProvider is a Provider implementation that binds to
 // a remote configuration service.
 type RemoteProvider struct {
         // Host is the base host name of the configuration service, e.g.,
         // "example.appspot.com".
         Host string
         // Insecure is true if the connection should use HTTP instead of HTTPS.
@@ skipping 86 matching lines @@
         case backend.AsAnonymous:
                 return auth.NoAuth
         case backend.AsService:
                 return auth.AsSelf
         case backend.AsUser:
                 return auth.AsUser
         default:
                 panic(fmt.Errorf("unknown config Authority (%d)", a))
         }
 }