app.yaml

application: sample
version: one
runtime: go
api_version: go1

skip_files:
- script.go

handlers:

- url: /_ah/remote_api
  script: _go_app
  login: admin

- url: /.*
  script: _go_app

hello.go

package hello

import (
	_ "appengine/remote_api"
	"fmt"
	"net/http"
)

func init() {
	http.HandleFunc("/", handler)
}

func handler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, "Hello, world!")
}

output

$ goapp deploy -application pndtest4
01:07 AM Application: pndtest4 (was: sample); version: one
01:07 AM Host: appengine.google.com
01:07 AM
Starting update of app: pndtest4, version: one
01:07 AM Getting current resource limits.
Email: [email protected]
Password for [email protected]:
01:07 AM Scanning files on local disk.
01:07 AM Cloning 2 application files.
01:07 AM Uploading 2 files and blobs.
01:07 AM Uploaded 2 files and blobs
01:07 AM Compilation starting.
01:07 AM Compilation: 1 files left.
01:07 AM Compilation completed.
01:07 AM Starting deployment.
01:07 AM Checking if deployment succeeded.
01:07 AM Deployment successful.
01:07 AM Checking if updated app version is serving.
01:07 AM Completed update of app: pndtest4, version: one

$ goapp run ./script.go -host one-dot-pndtest4.appspot.com -email [email protected] -password_file [omitted] -kind_name SampleEntity delete
2014/08/06 01:08:15 appengine: not running under devappserver2; using some default configuration
2014/08/06 01:08:16 Successfully deleted 0 keys

$ goapp run ./script.go -host one-dot-pndtest4.appspot.com -email [email protected] -password_file [omitted] -kind_name SampleEntity add
2014/08/06 01:08:21 appengine: not running under devappserver2; using some default configuration
2014/08/06 01:08:25 Successfully created 40 entities

$ goapp run ./script.go -host one-dot-pndtest4.appspot.com -email [email protected] -password_file [omitted] -kind_name SampleEntity delete
2014/08/06 01:08:30 appengine: not running under devappserver2; using some default configuration
2014/08/06 01:08:30 Failed during query to get keys: API error 1 (datastore_v3: BAD_REQUEST): invalid handle: 4904724477798395918
exit status 1

$ goapp run ./script.go -host one-dot-pndtest4.appspot.com -email [email protected] -password_file [omitted] -kind_name SampleEntity delete_wi
th_limit
2014/08/06 01:08:37 appengine: not running under devappserver2; using some default configuration
2014/08/06 01:08:38 Successfully deleted 40 keys

$ goapp run ./script.go -host one-dot-pndtest4.appspot.com -email [email protected] -password_file [omitted] -kind_name SampleEntity delete
2014/08/06 01:08:44 appengine: not running under devappserver2; using some default configuration
2014/08/06 01:08:44 Successfully deleted 0 keys

script.go

package main

import (
	"appengine/datastore"
	"appengine/remote_api"
	"errors"
	"flag"
	"io/ioutil"
	"log"
	"net/http"
	"net/http/cookiejar"
	"net/url"
	"regexp"
	"strings"
)

const NUM_ENTITIES_TO_INSERT = 40
const QUERY_FETCH_LIMIT = 1000

var (
	host         = flag.String("host", "", "hostname of application")
	email        = flag.String("email", "", "email of an admin user for the application")
	passwordFile = flag.String("password_file", "", "file which contains the user's password")
	kindName     = flag.String("kind_name", "", "name of the kind (an empty one) to be used")
)

func main() {
	flag.Parse()

	mode := flag.Arg(0)

	if *host == "" || *email == "" || *passwordFile == "" || *kindName == "" || flag.Arg(0) == "" {
		log.Fatalf("-host, -email, -passwordFile, -kindName and (add|delete|delete_with_limit) are required")
	}

	raw_password, err := ioutil.ReadFile(*passwordFile)
	if err != nil {
		log.Fatalf("Failed while reading password file %a: %v", *passwordFile, err)
	}
	password := strings.TrimSpace(string(raw_password))

	client := clientLoginClient(*host, *email, password)

	context, err := remote_api.NewRemoteContext(*host, client)
	if err != nil {
		log.Fatalf("Failed to create context: %v", err)
	}

	switch mode {
	case "delete":
		keys, err := datastore.NewQuery(*kindName).
			KeysOnly().
			GetAll(context, nil)
		if err != nil {
			log.Fatalf("Failed during query to get keys: %v", err)
		}

		if err := datastore.DeleteMulti(context, keys); err != nil {
			log.Fatalf("Failed during key deletion: %v", err)
		}

		log.Printf("Successfully deleted %v keys", len(keys))
	case "delete_with_limit":
		keys, err := datastore.NewQuery(*kindName).
			Limit(QUERY_FETCH_LIMIT).
			KeysOnly().
			GetAll(context, nil)
		if err != nil {
			log.Fatalf("Failed during query to get keys: %v", err)
		}

		if err := datastore.DeleteMulti(context, keys); err != nil {
			log.Fatalf("Failed during key deletion: %v", err)
		}

		log.Printf("Successfully deleted %v keys", len(keys))
	case "add":
		entities := make([]datastore.PropertyList, NUM_ENTITIES_TO_INSERT)
		keys := make([]*datastore.Key, NUM_ENTITIES_TO_INSERT)
		for i := 0; i < NUM_ENTITIES_TO_INSERT; i++ {
			keys[i] = datastore.NewIncompleteKey(context, *kindName, nil)
		}
		keys, err := datastore.PutMulti(context, keys, entities)
		if err != nil {
			log.Fatalf("Failed while inserting entities: %v", err)
		}

		log.Printf("Successfully created %v entities", len(keys))
	}
}

// Blatantly copied from demos/remote_api/datastore_info.go
func clientLoginClient(host, email, password string) *http.Client {
	jar, err := cookiejar.New(nil)
	if err != nil {
		log.Fatalf("failed to make cookie jar: %v", err)
	}
	client := &http.Client{
		Jar: jar,
	}

	v := url.Values{}
	v.Set("Email", email)
	v.Set("Passwd", password)
	v.Set("service", "ah")
	v.Set("source", "Misc-remote_api-0.1")
	v.Set("accountType", "HOSTED_OR_GOOGLE")

	resp, err := client.PostForm("https://www.google.com/accounts/ClientLogin", v)
	if err != nil {
		log.Fatalf("could not post login: %v", err)
	}
	defer resp.Body.Close()

	body, err := ioutil.ReadAll(resp.Body)
	if resp.StatusCode != http.StatusOK {
		log.Fatalf("unsuccessful request: status %d; body %q", resp.StatusCode, body)
	}
	if err != nil {
		log.Fatalf("unable to read response: %v", err)
	}

	m := regexp.MustCompile(`Auth=(\S+)`).FindSubmatch(body)
	if m == nil {
		log.Fatalf("no auth code in response %q", body)
	}
	auth := string(m[1])

	u := &url.URL{
		Scheme:   "https",
		Host:     host,
		Path:     "/_ah/login",
		RawQuery: "continue=/&auth=" + url.QueryEscape(auth),
	}

	// Disallow redirects.
	redirectErr := errors.New("stopping redirect")
	client.CheckRedirect = func(req *http.Request, via []*http.Request) error {
		return redirectErr
	}

	resp, err = client.Get(u.String())
	if urlErr, ok := err.(*url.Error); !ok || urlErr.Err != redirectErr {
		log.Fatalf("could not get auth cookies: %v", err)
	}
	defer resp.Body.Close()

	body, err = ioutil.ReadAll(resp.Body)
	if resp.StatusCode != http.StatusFound {
		log.Fatalf("unsuccessful request: status %d; body %q", resp.StatusCode, body)
	}

	client.CheckRedirect = nil
	return client
}