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Google Cloud Client Libraries for Go

GoDoc

Go packages for Google Cloud Platform services.

import "cloud.google.com/go"

To install the packages on your system,

$ go get -u cloud.google.com/go/...

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

NOTE: Github repo is a mirror of https://code.googlesource.com/gocloud.

News

March 17, 2017

Breaking Pubsub changes.

  • Publish is now asynchronous (announcement).
  • Subscription.Pull replaced by Subscription.Receive, which takes a callback (announcement).
  • Message.Done replaced with Message.Ack and Message.Nack.

February 14, 2017

Release of a client library for Spanner. See the blog post.

Note that although the Spanner service is beta, the Go client library is alpha.

Older news

Supported APIs

Google API Status Package
Datastore stable cloud.google.com/go/datastore
Storage stable cloud.google.com/go/storage
Bigtable beta cloud.google.com/go/bigtable
BigQuery beta cloud.google.com/go/bigquery
Logging stable cloud.google.com/go/logging
Monitoring alpha cloud.google.com/go/monitoring/apiv3
Pub/Sub alpha cloud.google.com/go/pubsub
Vision beta cloud.google.com/go/vision
Language alpha cloud.google.com/go/language/apiv1
Speech alpha cloud.google.com/go/speech/apiv1
Spanner alpha cloud.google.com/go/spanner
Translation beta cloud.google.com/go/translate

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 https://godoc.org/cloud.google.com/go

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. You can see which versions are currently supported by looking at the lines following go: in .travis.yml.

Authorization

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.WithServiceAccountFile to the NewClient function of the desired package. For example:

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

You can exert more control over authorization by using the golang.org/x/oauth2 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 {
	log.Fatal(err)
}

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 {
	log.Fatal(err)
}

Cloud Storage GoDoc

Example Usage

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

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

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 {
	log.Fatal(err)
}

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 {
	log.Fatal(err)
}

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

Cloud 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 {
		break
	}
	if err != nil {
		// TODO: Handle error.
	}
	fmt.Println(values)
}

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 {
	log.Fatal(err)
}
// Simple Reads And Writes
_, err = client.Apply(ctx, []*spanner.Mutation{
	spanner.Insert("Users",
		[]string{"name", "email"},
		[]interface{}{"alice", "a@example.com"})})
if err != nil {
	log.Fatal(err)
}
row, err := client.Single().ReadRow(ctx, "Users",
	spanner.Key{"alice"}, []string{"email"})
if err != nil {
	log.Fatal(err)
}

Contributing

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.