main.go

package main

import (
	"cloud.google.com/go/datastore"
	"fmt"
	"golang.org/x/net/context"
	"log"
	"net/http"
	"os"
	"time"
)

type Entity struct {
	Value string
}

func main() {
	http.HandleFunc("/", handle)

	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
		log.Printf("Defaulting to port %s", port)
	}

	log.Printf("Listening on port %s", port)
	log.Fatal(http.ListenAndServe(fmt.Sprintf(":%s", port), nil))
}

func timer(start time.Time, name string) {
	elapsed := time.Since(start)
	log.Printf("%s took %s", name, elapsed)
}

var dsClient *datastore.Client

func makeClient(ctx context.Context) (*datastore.Client, error) {
	defer timer(time.Now(), "makeClient")

	if dsClient == nil {
		var err error
		dsClient, err = datastore.NewClient(ctx, "my-project")
		if err != nil {
			return nil, err
		}
	}

	return dsClient, nil
}

func put(ctx context.Context, dsClient *datastore.Client) (*datastore.Key, error) {
	defer timer(time.Now(), "put")

	key := datastore.IDKey("RandomEntity", 0, nil)
	key.Namespace = "test-datatest"

	entity := &Entity{
		Value: "hello world",
	}

	return dsClient.Put(ctx, key, entity)
}

func get(ctx context.Context, dsClient *datastore.Client, key *datastore.Key) (*Entity, error) {
	defer timer(time.Now(), "get")

	e := &Entity{}
	return e, dsClient.Get(ctx, key, e)
}

func handle(w http.ResponseWriter, r *http.Request) {
	defer timer(time.Now(), "request")

	ctx := r.Context()

	client, err := makeClient(ctx)
	if err != nil {
		fmt.Fprintf(w, "client error %v\n", err)
		return
	}

	for i := 0; i < 3; i++ {
		key, err := put(ctx, client)
		if err != nil {
			fmt.Fprintf(w, "put error %v\n", err)
			return
		}

		_, err = get(ctx, client, key)
		if err != nil {
			fmt.Fprintf(w, "get error %v\n", err)
			return
		}
	}

	fmt.Fprintln(w, "Hello, world!")
}