Andrea Spacca
README.md
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, do not clone the repo. Instead use
$ 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
- BigQuery
- Stackdriver Logging
- Cloud Spanner
News
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
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.
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.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
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 
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 
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)
}
BigQuery 
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 
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 
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.