datastore: add error checking to Query.nextBatch

Currently, nextBatch will panic if the given query is somehow invalid.
This can happen when Filter is invoked with an invalid type:

type MyType int
var v MyType = 1
q := datastore.NewQuery("MyKind").Filter("fld=", v)
n, err := c.Count(ctx, q)

This happens because the type validation happens while running the query
and converting the query to protobuf (via toProto). If this fails, the
iterator will set an error, however nextBatch is not checking the error.
Therefore the iterator is in an invalid state and certain fields are
nil. When the user invokes Next again, the call panics (in nextBatch).

This CL fixes this problem by having nextBatch check the iterator's err

Fixes #1306

Change-Id: I8cfe48a17258a1ab4a18580230bffc51e3b2c75c
Reviewed-by: Jean de Klerk <>
2 files changed
tree: 329186838aea95ab7f816a07aa40ce0ba418159f
  9. asset/
  10. authexample_test.go
  11. bigquery/
  12. bigtable/
  13. civil/
  14. cloud.go
  15. cloudtasks/
  16. cmd/
  17. compute/
  18. container/
  19. containeranalysis/
  20. dataproc/
  21. datastore/
  22. debugger/
  23. dialogflow/
  24. dlp/
  25. errorreporting/
  26. examples_test.go
  27. expr/
  28. firestore/
  29. functions/
  30. go.mod
  31. go.sum
  32. httpreplay/
  33. iam/
  34. internal/
  35. irm/
  37. keys.tar.enc
  38. kms/
  39. language/
  40. license_test.go
  41. logging/
  42. longrunning/
  43. monitoring/
  45. oslogin/
  46. profiler/
  47. pubsub/
  48. redis/
  50. rpcreplay/
  52. scheduler/
  53. securitycenter/
  54. spanner/
  55. speech/
  56. storage/
  57. talent/
  58. texttospeech/
  59. tools.go
  60. trace/
  61. translate/
  62. videointelligence/
  63. vision/

Google Cloud Client Libraries for Go


Go packages for Google Cloud Platform services.

import ""

To install the packages on your system, do not clone the repo. Instead use

$ go get -u

NOTE: Some of these packages are under development, and may occasionally make backwards-incompatible changes.

NOTE: Github repo is a mirror of


7 August 2018

As of November 1, the code in the repo will no longer support Go versions 1.8 and earlier. No one other than AppEngine users should be on those old versions, and AppEngine Standard and Flex will stop supporting new deployments with those versions on that date.

Changes have been moved to CHANGES.

Supported APIs

Google APIStatusPackage
Data Loss
Text To

Alpha status: the API is still being actively developed. As a result, it might change in backward-incompatible ways and is not recommended for production use.

Beta status: the API is largely complete, but still has outstanding features and bugs to be addressed. There may be minor backwards-incompatible changes where necessary.

Stable status: the API is mature and ready for production use. We will continue addressing bugs and feature requests.

Documentation and examples are available at

Visit or join the google-api-go-announce group for updates on these packages.

Go Versions Supported

We support the two most recent major versions of Go. If Google App Engine uses an older version, we support that as well.


By default, each API will use Google Application Default Credentials for authorization credentials used in calling the API endpoints. This will allow your application to run in many environments without requiring explicit configuration.

client, err := storage.NewClient(ctx)

To authorize using a JSON key file, pass option.WithCredentialsFile to the NewClient function of the desired package. For example:

client, err := storage.NewClient(ctx, option.WithCredentialsFile("path/to/keyfile.json"))

You can exert more control over authorization by using the package to create an oauth2.TokenSource. Then pass option.WithTokenSource to the NewClient function: snip:# (auth-ts)

tokenSource := ...
client, err := storage.NewClient(ctx, option.WithTokenSource(tokenSource))

Cloud Datastore GoDoc

Example Usage

First create a datastore.Client to use throughout your application:

client, err := datastore.NewClient(ctx, "my-project-id")
if err != nil {

Then use that client to interact with the API:

type Post struct {
	Title       string
	Body        string `datastore:",noindex"`
	PublishedAt time.Time
keys := []*datastore.Key{
	datastore.NameKey("Post", "post1", nil),
	datastore.NameKey("Post", "post2", nil),
posts := []*Post{
	{Title: "Post 1", Body: "...", PublishedAt: time.Now()},
	{Title: "Post 2", Body: "...", PublishedAt: time.Now()},
if _, err := client.PutMulti(ctx, keys, posts); err != nil {

Cloud Storage GoDoc

Example Usage

First create a storage.Client to use throughout your application:

client, err := storage.NewClient(ctx)
if err != nil {
// Read the object1 from bucket.
rc, err := client.Bucket("bucket").Object("object1").NewReader(ctx)
if err != nil {
defer rc.Close()
body, err := ioutil.ReadAll(rc)
if err != nil {

Cloud Pub/Sub GoDoc

Example Usage

First create a pubsub.Client to use throughout your application:

client, err := pubsub.NewClient(ctx, "project-id")
if err != nil {

Then use the client to publish and subscribe:

// Publish "hello world" on topic1.
topic := client.Topic("topic1")
res := topic.Publish(ctx, &pubsub.Message{
	Data: []byte("hello world"),
// The publish happens asynchronously.
// Later, you can get the result from res:
msgID, err := res.Get(ctx)
if err != nil {

// Use a callback to receive messages via subscription1.
sub := client.Subscription("subscription1")
err = sub.Receive(ctx, func(ctx context.Context, m *pubsub.Message) {
	m.Ack() // Acknowledge that we've consumed the message.
if err != nil {

BigQuery GoDoc

Example Usage

First create a bigquery.Client to use throughout your application: snip:# (bq-1)

c, err := bigquery.NewClient(ctx, "my-project-ID")
if err != nil {
	// TODO: Handle error.

Then use that client to interact with the API: snip:# (bq-2)

// Construct a query.
q := c.Query(`
    SELECT year, SUM(number)
    FROM [bigquery-public-data:usa_names.usa_1910_2013]
    WHERE name = "William"
    GROUP BY year
    ORDER BY year
// Execute the query.
it, err := q.Read(ctx)
if err != nil {
	// TODO: Handle error.
// Iterate through the results.
for {
	var values []bigquery.Value
	err := it.Next(&values)
	if err == iterator.Done {
	if err != nil {
		// TODO: Handle error.

Stackdriver Logging GoDoc

Example Usage

First create a logging.Client to use throughout your application: snip:# (logging-1)

ctx := context.Background()
client, err := logging.NewClient(ctx, "my-project")
if err != nil {
	// TODO: Handle error.

Usually, you'll want to add log entries to a buffer to be periodically flushed (automatically and asynchronously) to the Stackdriver Logging service. snip:# (logging-2)

logger := client.Logger("my-log")
logger.Log(logging.Entry{Payload: "something happened!"})

Close your client before your program exits, to flush any buffered log entries. snip:# (logging-3)

err = client.Close()
if err != nil {
	// TODO: Handle error.

Cloud Spanner GoDoc

Example Usage

First create a spanner.Client to use throughout your application:

client, err := spanner.NewClient(ctx, "projects/P/instances/I/databases/D")
if err != nil {
// Simple Reads And Writes
_, err = client.Apply(ctx, []*spanner.Mutation{
		[]string{"name", "email"},
		[]interface{}{"alice", ""})})
if err != nil {
row, err := client.Single().ReadRow(ctx, "Users",
	spanner.Key{"alice"}, []string{"email"})
if err != nil {


Contributions are welcome. Please, see the CONTRIBUTING document for details. We‘re using Gerrit for our code reviews. Please don’t open pull requests against this repo, new pull requests will be automatically closed.

Please note that this project is released with a Contributor Code of Conduct. By participating in this project you agree to abide by its terms. See Contributor Code of Conduct for more information.