func ExampleNewKey_withParent() {
// [START key_with_parent]
parentKey := datastore.NameKey("TaskList", "default", nil)
taskKey := datastore.NameKey("Task", "sampleTask", parentKey)
// [END key_with_parent]
_ = taskKey // Use the task key for datastore operations.
}
func ExampleNewKey_withMultipleParents() {
// [START key_with_multilevel_parent]
userKey := datastore.NameKey("User", "alice", nil)
parentKey := datastore.NameKey("TaskList", "default", userKey)
taskKey := datastore.NameKey("Task", "sampleTask", parentKey)
// [END key_with_multilevel_parent]
_ = taskKey // Use the task key for datastore operations.
}
func ExampleQuery_EventualConsistency() {
// [START eventual_consistent_query]
ancestor := datastore.NameKey("TaskList", "default", nil)
query := datastore.NewQuery("Task").Ancestor(ancestor).EventualConsistency()
// [END eventual_consistent_query]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleQuery_Ancestor() {
// [START ancestor_query]
ancestor := datastore.NameKey("TaskList", "default", nil)
query := datastore.NewQuery("Task").Ancestor(ancestor)
// [END ancestor_query]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleQuery_keyFilter() {
// [START key_filter]
key := datastore.NameKey("Task", "someTask", nil)
query := datastore.NewQuery("Task").Filter("__key__ >", key)
// [END key_filter]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleClient_RunInTransaction() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
// Increment a counter.
// See https://cloud.google.com/appengine/articles/sharding_counters for
// a more scalable solution.
type Counter struct {
Count int
}
var count int
key := datastore.NameKey("Counter", "singleton", nil)
_, err = client.RunInTransaction(ctx, func(tx *datastore.Transaction) error {
var x Counter
if err := tx.Get(key, &x); err != nil && err != datastore.ErrNoSuchEntity {
return err
}
x.Count++
if _, err := tx.Put(key, &x); err != nil {
return err
}
count = x.Count
return nil
})
if err != nil {
// TODO: Handle error.
}
// The value of count is only valid once the transaction is successful
// (RunInTransaction has returned nil).
fmt.Printf("Count=%d\n", count)
}
func ExampleClient_Put() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
type Article struct {
Title string
Description string
Body string `datastore:",noindex"`
Author *datastore.Key
PublishedAt time.Time
}
newKey := datastore.IncompleteKey("Article", nil)
_, err = client.Put(ctx, newKey, &Article{
Title: "The title of the article",
Description: "The description of the article...",
Body: "...",
Author: datastore.NameKey("Author", "jbd", nil),
PublishedAt: time.Now(),
})
if err != nil {
// TODO: Handle error.
}
}
func ExampleClient_GetMulti() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
keys := []*datastore.Key{
datastore.NameKey("Post", "post1", nil),
datastore.NameKey("Post", "post2", nil),
datastore.NameKey("Post", "post3", nil),
}
posts := make([]Post, 3)
if err := client.GetMulti(ctx, keys, posts); err != nil {
// TODO: Handle error.
}
}
func ExampleClient_Delete() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
key := datastore.NameKey("Task", "sampletask", nil)
// [START delete]
err := client.Delete(ctx, key)
// [END delete]
_ = err // Make sure you check err.
}
func ExampleClient_Get() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
taskKey := datastore.NameKey("Task", "sampleTask", nil)
// [START lookup]
var task Task
err := client.Get(ctx, taskKey, &task)
// [END lookup]
_ = err // Make sure you check err.
}
func ExampleClient_PutMulti_interfaceSlice() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
keys := []*datastore.Key{
datastore.NameKey("Post", "post1", nil),
datastore.NameKey("Post", "post2", nil),
}
// PutMulti with an empty interface slice.
posts := []interface{}{
&Post{Title: "Post 1", PublishedAt: time.Now()},
&Post{Title: "Post 2", PublishedAt: time.Now()},
}
if _, err := client.PutMulti(ctx, keys, posts); err != nil {
// TODO: Handle error.
}
}
func ExampleClient_Delete() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
key := datastore.NameKey("Article", "articled1", nil)
if err := client.Delete(ctx, key); err != nil {
// TODO: Handle error.
}
}
func Example_metadataPropertiesForKind() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
// [START property_by_kind_run_query]
kindKey := datastore.NameKey("__kind__", "Task", nil)
query := datastore.NewQuery("__property__").Ancestor(kindKey)
type Prop struct {
Repr []string `datastore:"property_representation"`
}
var props []Prop
keys, err := client.GetAll(ctx, query, &props)
// [END property_by_kind_run_query]
_ = err // Check error.
_ = keys // Use keys to find property names, and props for their representations.
}
func ExampleTransaction_runQuery() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
// [START transactional_single_entity_group_read_only]
tx, err := client.NewTransaction(ctx)
if err != nil {
log.Fatalf("client.NewTransaction: %v", err)
}
defer tx.Rollback() // Transaction only used for read.
ancestor := datastore.NameKey("TaskList", "default", nil)
query := datastore.NewQuery("Task").Ancestor(ancestor).Transaction(tx)
var tasks []Task
_, err = client.GetAll(ctx, query, &tasks)
// [END transactional_single_entity_group_read_only]
_ = err // Check error.
}
func ExampleTransaction_insert() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
task := Task{} // Populated with appropriate data.
taskKey := datastore.NameKey("Task", "sampleTask", nil)
// [START insert]
_, err := client.RunInTransaction(ctx, func(tx *datastore.Transaction) error {
// We first check that there is no entity stored with the given key.
var empty Task
if err := tx.Get(taskKey, &empty); err != datastore.ErrNoSuchEntity {
return err
}
// If there was no matching entity, store it now.
_, err := tx.Put(taskKey, &task)
return err
})
// [END insert]
_ = err // Make sure you check err.
}
func ExampleClient_Put() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
// [START entity_with_parent]
parentKey := datastore.NameKey("TaskList", "default", nil)
key := datastore.IncompleteKey("Task", parentKey)
task := Task{
Category: "Personal",
Done: false,
Priority: 4,
Description: "Learn Cloud Datastore",
}
// A complete key is assigned to the entity when it is Put.
var err error
key, err = client.Put(ctx, key, &task)
// [END entity_with_parent]
_ = err // Make sure you check err.
}
func ExampleClient_Get() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
type Article struct {
Title string
Description string
Body string `datastore:",noindex"`
Author *datastore.Key
PublishedAt time.Time
}
key := datastore.NameKey("Article", "articled1", nil)
article := &Article{}
if err := client.Get(ctx, key, article); err != nil {
// TODO: Handle error.
}
}
func ExampleClient_NewTransaction() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
// TODO: Handle error.
}
const retries = 3
// Increment a counter.
// See https://cloud.google.com/appengine/articles/sharding_counters for
// a more scalable solution.
type Counter struct {
Count int
}
key := datastore.NameKey("counter", "CounterA", nil)
var tx *datastore.Transaction
for i := 0; i < retries; i++ {
tx, err = client.NewTransaction(ctx)
if err != nil {
break
}
var c Counter
if err = tx.Get(key, &c); err != nil && err != datastore.ErrNoSuchEntity {
break
}
c.Count++
if _, err = tx.Put(key, &c); err != nil {
break
}
// Attempt to commit the transaction. If there's a conflict, try again.
if _, err = tx.Commit(); err != datastore.ErrConcurrentTransaction {
break
}
}
if err != nil {
// TODO: Handle error.
}
}
func ExampleTransaction_getOrCreate() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
key := datastore.NameKey("Task", "sampletask", nil)
// [START transactional_get_or_create]
_, err := client.RunInTransaction(ctx, func(tx *datastore.Transaction) error {
var task Task
if err := tx.Get(key, &task); err != datastore.ErrNoSuchEntity {
return err
}
_, err := tx.Put(key, &Task{
Category: "Personal",
Done: false,
Priority: 4,
Description: "Learn Cloud Datastore",
})
return err
})
// [END transactional_get_or_create]
_ = err // Check error.
}
func ExampleTransaction_update() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
taskKey := datastore.NameKey("Task", "sampleTask", nil)
// [START update]
tx, err := client.NewTransaction(ctx)
if err != nil {
log.Fatalf("client.NewTransaction: %v", err)
}
var task Task
if err := tx.Get(taskKey, &task); err != nil {
log.Fatalf("tx.Get: %v", err)
}
task.Priority = 5
if _, err := tx.Put(taskKey, task); err != nil {
log.Fatalf("tx.Put: %v", err)
}
if _, err := tx.Commit(); err != nil {
log.Fatalf("tx.Commit: %v", err)
}
// [END update]
}
func ExampleNameKey() {
// Key with string ID.
k := datastore.NameKey("Article", "article8", nil)
_ = k // TODO: Use key.
}
func ExampleNewKey() {
// [START named_key]
taskKey := datastore.NameKey("Task", "sampletask", nil)
// [END named_key]
_ = taskKey // Use the task key for datastore operations.
}
// makeRequests makes some requests.
// req is an incoming request used to construct the trace. traceClient is the
// client used to upload the trace. rt is the trace client's http client's
// transport. This is used to retrieve the trace uploaded by the client, if
// any. If expectTrace is true, we expect a trace will be uploaded. If
// synchronous is true, the call to Finish is expected not to return before the
// client has uploaded any traces.
func makeRequests(t *testing.T, req *http.Request, traceClient *Client, rt *fakeRoundTripper, synchronous bool, expectTrace bool) *http.Request {
span := traceClient.SpanFromRequest(req)
ctx := NewContext(context.Background(), span)
// An HTTP request.
{
req2, err := http.NewRequest("GET", "http://example.com/bar", nil)
if err != nil {
t.Fatal(err)
}
resp := &http.Response{StatusCode: 200}
s := span.NewRemoteChild(req2)
s.Finish(WithResponse(resp))
}
// An autogenerated API call.
{
rt := &fakeRoundTripper{reqc: make(chan *http.Request, 1)}
hc := &http.Client{Transport: rt}
computeClient, err := compute.New(hc)
if err != nil {
t.Fatal(err)
}
_, err = computeClient.Zones.List(testProjectID).Context(ctx).Do()
if err != nil {
t.Fatal(err)
}
}
// A cloud library call that uses the autogenerated API.
{
rt := &fakeRoundTripper{reqc: make(chan *http.Request, 1)}
hc := &http.Client{Transport: rt}
storageClient, err := storage.NewClient(context.Background(), option.WithHTTPClient(hc))
if err != nil {
t.Fatal(err)
}
var objAttrsList []*storage.ObjectAttrs
it := storageClient.Bucket("testbucket").Objects(ctx, nil)
for {
objAttrs, err := it.Next()
if err != nil && err != iterator.Done {
t.Fatal(err)
}
if err == iterator.Done {
break
}
objAttrsList = append(objAttrsList, objAttrs)
}
}
// A cloud library call that uses grpc internally.
for _, fail := range []bool{false, true} {
srv, err := testutil.NewServer()
if err != nil {
t.Fatalf("creating test datastore server: %v", err)
}
dspb.RegisterDatastoreServer(srv.Gsrv, &fakeDatastoreServer{fail: fail})
srv.Start()
conn, err := grpc.Dial(srv.Addr, grpc.WithInsecure(), EnableGRPCTracingDialOption)
if err != nil {
t.Fatalf("connecting to test datastore server: %v", err)
}
datastoreClient, err := datastore.NewClient(ctx, testProjectID, option.WithGRPCConn(conn))
if err != nil {
t.Fatalf("creating datastore client: %v", err)
}
k := datastore.NameKey("Entity", "stringID", nil)
e := new(datastore.Entity)
datastoreClient.Get(ctx, k, e)
}
done := make(chan struct{})
go func() {
if synchronous {
err := span.FinishWait()
if err != nil {
t.Errorf("Unexpected error from span.FinishWait: %v", err)
}
} else {
span.Finish()
}
done <- struct{}{}
}()
if !expectTrace {
<-done
select {
case <-rt.reqc:
t.Errorf("Got a trace, expected none.")
case <-time.After(5 * time.Millisecond):
}
return nil
} else if !synchronous {
<-done
return <-rt.reqc
} else {
select {
case <-done:
t.Errorf("Synchronous Finish didn't wait for trace upload.")
return <-rt.reqc
case <-time.After(5 * time.Millisecond):
r := <-rt.reqc
<-done
return r
}
}
}