Reland: Refactor current GAE abstraction library to be free of the SDK*

go/src/infra/gae/epservice/example/service_cas.go

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package example
 
 import (
         "golang.org/x/net/context"
-        "infra/gae/libs/wrapper"
-        "infra/gae/libs/wrapper/gae"
+        "infra/gae/libs/gae"
+        "infra/gae/libs/gae/prod"
 
         "github.com/GoogleCloudPlatform/go-endpoints/endpoints"
 )
 
 // CASReq is the input for the CAS RPC
 type CASReq struct {
         Name string `endpoints:"required"`
 
         OldVal int64 `json:",string"`
         NewVal int64 `json:",string"`
 }
 
 // CAS does an atomic compare-and-swap on a counter.
-func (Example) CAS(c endpoints.Context, r *CASReq) (err error) {
+func (Example) CAS(c context.Context, r *CASReq) (err error) {
         success := false
-        ds := wrapper.GetDS(gae.Use(context.Background(), c))
-        err = ds.RunInTransaction(func(context.Context) error {
-                ctr := &Counter{ID: r.Name}
-                if err := ds.Get(ctr); err != nil {
+        c = prod.Use(c)
+        err = gae.GetRDS(c).RunInTransaction(func(c context.Context) error {
+                rds := gae.GetRDS(c)
+                key := rds.NewKey("Counter", r.Name, 0, nil)
+                ctr := &Counter{}
+                if err := rds.Get(key, ctr); err != nil {
                         return err
                 }
                 if ctr.Val == r.OldVal {
                         success = true
                         ctr.Val = r.NewVal
-                        _, err := ds.Put(ctr)
+                        _, err := rds.Put(key, ctr)
                         return err
                 }
                 success = false
                 return nil
         }, nil)
         if err == nil && !success {
                 err = endpoints.ConflictError
         }
         return
 }
 
 func init() {
         mi["CAS"] = &endpoints.MethodInfo{
                 Path: "counter/{Name}/cas",
                 Desc: "Compare and swap a counter value",
         }
 }