cloud

README

Google Cloud Client Libraries for Go

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
• Supported APIs
• Go Versions Supported
• Authorization
• Cloud Datastore
• Cloud Storage
• Cloud Pub/Sub
• Cloud BigQuery
• Stackdriver Logging
• Cloud Spanner

News

March 22, 2018

v0.20.

• bigquery: Support SchemaUpdateOptions for load jobs.

• bigtable:

  • Add SampleRowKeys.
  • cbt: Support union, intersection GCPolicy.
  • Retry admin RPCS.
  • Add trace spans to retries.

• datastore: Add OpenCensus tracing.

• firestore:

  • Fix queries involving Null and NaN.
  • Allow Timestamp protobuffers for time values.

• logging: Add a WriteTimeout option.

• spanner: Support Batch API.

• storage: Add OpenCensus tracing.

February 26, 2018

v0.19.0

• bigquery:

  • Support customer-managed encryption keys.

• bigtable:

  • Improved emulator support.
  • Support GetCluster.

• datastore:

  • Add general mutations.
  • Support pointer struct fields.
  • Support transaction options.

• firestore:

  • Add Transaction.GetAll.
  • Support document cursors.

• logging:

  • Support concurrent RPCs to the service.
  • Support per-entry resources.

• profiler:

  • Add config options to disable heap and thread profiling.
  • Read the project ID from $GOOGLE_CLOUD_PROJECT when it's set.

• pubsub:

  • BEHAVIOR CHANGE: Release flow control after ack/nack (instead of after the callback returns).
  • Add SubscriptionInProject.
  • Add OpenCensus instrumentation for streaming pull.

• storage:

  • Support CORS.

January 18, 2018

v0.18.0

• bigquery:

  • Marked stable.
  • Schema inference of nullable fields supported.
  • Added TimePartitioning to QueryConfig.

• firestore: Data provided to DocumentRef.Set with a Merge option can contain Delete sentinels.

• logging: Clients can accept parent resources other than projects.

• pubsub:

  • pubsub/pstest: A lighweight fake for pubsub. Experimental; feedback welcome.
  • Support updating more subscription metadata: AckDeadline, RetainAckedMessages and RetentionDuration.

• oslogin/apiv1beta: New client for the Cloud OS Login API.

• rpcreplay: A package for recording and replaying gRPC traffic.

• spanner:

  • Add a ReadWithOptions that supports a row limit, as well as an index.
  • Support query plan and execution statistics.
  • Added OpenCensus support.

• storage: Clarify checksum validation for gzipped files (it is not validated when the file is served uncompressed).

December 11, 2017

v0.17.0

• firestore BREAKING CHANGES:

  • Remove UpdateMap and UpdateStruct; rename UpdatePaths to Update. Change docref.UpdateMap(ctx, map[string]interface{}{"a.b", 1}) to docref.Update(ctx, []firestore.Update{{Path: "a.b", Value: 1}})

    Change docref.UpdateStruct(ctx, []string{"Field"}, aStruct) to docref.Update(ctx, []firestore.Update{{Path: "Field", Value: aStruct.Field}})

  • Rename MergePaths to Merge; require args to be FieldPaths

  • A value stored as an integer can be read into a floating-point field, and vice versa.

• bigtable/cmd/cbt:
  • Support deleting a column.
  • Add regex option for row read.
• spanner: Mark stable.
• storage:
  • Add Reader.ContentEncoding method.
  • Fix handling of SignedURL headers.
• bigquery:
  • If Uploader.Put is called with no rows, it returns nil without making a call.
  • Schema inference supports the "nullable" option in struct tags for non-required fields.
  • TimePartitioning supports "Field".

Older news

Supported APIs

Google API	Status	Package
BigQuery	stable	cloud.google.com/go/bigquery
Bigtable	stable	cloud.google.com/go/bigtable
Container	alpha	cloud.google.com/go/container/apiv1
Data Loss Prevention	alpha	cloud.google.com/go/dlp/apiv2beta1
Datastore	stable	cloud.google.com/go/datastore
Debugger	alpha	cloud.google.com/go/debugger/apiv2
ErrorReporting	alpha	cloud.google.com/go/errorreporting
Firestore	beta	cloud.google.com/go/firestore
Language	stable	cloud.google.com/go/language/apiv1
Logging	stable	cloud.google.com/go/logging
Monitoring	beta	cloud.google.com/go/monitoring/apiv3
OS Login	alpha	cloud.google.com/compute/docs/oslogin/rest
Pub/Sub	beta	cloud.google.com/go/pubsub
Spanner	stable	cloud.google.com/go/spanner
Speech	stable	cloud.google.com/go/speech/apiv1
Storage	stable	cloud.google.com/go/storage
Translation	stable	cloud.google.com/go/translate
Video Intelligence	beta	cloud.google.com/go/videointelligence/apiv1beta1
Vision	stable	cloud.google.com/go/vision/apiv1

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

• About Cloud Datastore
• Activating the API for your project
• API documentation
• Go client documentation
• Complete sample program

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

• About Cloud Storage
• API documentation
• Go client documentation
• Complete sample programs

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

• About Cloud Pubsub
• API documentation
• Go client documentation
• Complete sample programs

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

• About Cloud BigQuery
• API documentation
• Go client documentation
• Complete sample programs

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

• About Stackdriver Logging
• API documentation
• Go client documentation
• Complete sample programs

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

• About Cloud Spanner
• API documentation
• Go client documentation

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.

Documentation

Overview

Package cloud is the root of the packages used to access Google Cloud Services. See https://godoc.org/cloud.google.com/go for a full list of sub-packages.

Examples in this package show ways to authorize and authenticate the sub packages.

Connection Pooling

Connection pooling differs in clients based on their transport. Cloud clients either rely on HTTP or gRPC transports to communicate with Google Cloud.

Cloud clients that use HTTP (bigquery, compute, storage, and translate) rely on the underlying HTTP transport to cache connections for later re-use. These are cached to the default http.MaxIdleConns and http.MaxIdleConnsPerHost settings in http.DefaultTransport.

For gPRC clients (all others in this repo), connection pooling is configurable. Users of cloud client libraries may specify option.WithGRPCConnectionPool(n) as a client option to NewClient calls. This configures the underlying gRPC connections to be pooled and addressed in a round robin fashion.

Example (ApplicationDefaultCredentials)

package main

import (
	"cloud.google.com/go/datastore"
	"golang.org/x/net/context"
)

func main() {
	// Google Application Default Credentials is the recommended way to authorize
	// and authenticate clients.
	//
	// See the following link on how to create and obtain Application Default Credentials:
	// https://developers.google.com/identity/protocols/application-default-credentials.
	client, err := datastore.NewClient(context.Background(), "project-id")
	if err != nil {
		// TODO: handle error.
	}
	_ = client // Use the client.
}

Example (ServiceAccountFile)

package main

import (
	"cloud.google.com/go/datastore"
	"golang.org/x/net/context"
	"google.golang.org/api/option"
)

func main() {
	// Use a JSON key file associated with a Google service account to
	// authenticate and authorize. Service Account keys can be created and
	// downloaded from https://console.developers.google.com/permissions/serviceaccounts.
	//
	// Note: This example uses the datastore client, but the same steps apply to
	// the other client libraries underneath this package.
	client, err := datastore.NewClient(context.Background(),
		"project-id", option.WithServiceAccountFile("/path/to/service-account-key.json"))
	if err != nil {
		// TODO: handle error.
	}
	_ = client // Use the client.
}