func ExampleQuery() {
ctx := context.Background()
client, err := datastore.NewClient(ctx, "project-id")
if err != nil {
log.Fatal(err)
}
// Count the number of the post entities.
q := datastore.NewQuery("Post")
n, err := client.Count(ctx, q)
if err != nil {
log.Fatal(err)
}
log.Println("There are %d posts.", n)
// List the posts published since yesterday.
yesterday := time.Now().Add(-24 * time.Hour)
q = datastore.NewQuery("Post").Filter("PublishedAt >", yesterday)
it := client.Run(ctx, q)
// Use the iterator.
_ = it
// Order the posts by the number of comments they have recieved.
datastore.NewQuery("Post").Order("-Comments")
// Start listing from an offset and limit the results.
datastore.NewQuery("Post").Offset(20).Limit(10)
}
func ExampleQuery_kindless() {
var lastSeenKey *datastore.Key
// [START kindless_query]
query := datastore.NewQuery("").Filter("__key__ >", lastSeenKey)
// [END kindless_query]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func (ds *Datastore) GetEntity(t, subject string) (reply []x.Instruction, rerr error) {
skey := datastore.NewKey(ds.ctx, t+"Entity", subject, 0, nil)
log.Infof("skey: %+v", skey)
dkeys, rerr := datastore.NewQuery(t+"Instruction").Ancestor(skey).GetAll(ds.ctx, &reply)
log.Debugf("Got num keys: %+v", len(dkeys))
return
}
func (loc *INodeDBSSLocator) tryLocateOnce(history int) (string, error) {
start := time.Now()
cli, err := loc.cfg.getClient(context.TODO())
if err != nil {
return "", err
}
dstx, err := cli.NewTransaction(context.TODO(), datastore.Serializable)
if err != nil {
return "", err
}
q := datastore.NewQuery(kindINodeDBSS).Ancestor(loc.rootKey).Order("-TxID").Offset(history).Limit(1).Transaction(dstx)
it := cli.Run(context.TODO(), q)
var e sslocentry
if _, err := it.Next(&e); err != nil {
dstx.Rollback()
if err == datastore.Done {
return "", EEMPTY
}
return "", err
}
if _, err := dstx.Commit(); err != nil {
return "", err
}
logger.Infof(sslog, "LocateSnapshot(%d) took %s. Found entry: %+v", history, time.Since(start), e)
return e.BlobPath, nil
}
func query() (key *AuthorizedKey, username string, err error) {
ctx, err := connect()
if err != nil {
return
}
rawFingerprint, err := decodeFingerprint(fingerprint)
if err != nil {
return
}
key = new(AuthorizedKey)
it := datastore.NewQuery(keyKind).Filter("Fingerprint =", rawFingerprint).Limit(1).Run(ctx)
_, err = it.Next(key)
if err != nil {
return
}
var coder Coder
err = datastore.Get(ctx, key.Coder, &coder)
if err != nil {
return
}
username = coder.Nickname
return
}
func ExampleIterator_Cursor() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
cursorStr := ""
// [START cursor_paging]
const pageSize = 5
query := datastore.NewQuery("Tasks").Limit(pageSize)
if cursorStr != "" {
cursor, err := datastore.DecodeCursor(cursorStr)
if err != nil {
log.Fatalf("Bad cursor %q: %v", cursorStr, err)
}
query = query.Start(cursor)
}
// Read the tasks.
var tasks []Task
var task Task
it := client.Run(ctx, query)
_, err := it.Next(&task)
for err == nil {
tasks = append(tasks, task)
_, err = it.Next(&task)
}
if err != datastore.Done {
log.Fatalf("Failed fetching results: %v", err)
}
// Get the cursor for the next page of results.
nextCursor, err := it.Cursor()
// [END cursor_paging]
_ = err // Check the error.
_ = nextCursor // Use nextCursor.String as the next page's token.
}
func ExampleQuery_keyFilter() {
ctx := context.Background()
// [START key_filter]
key := datastore.NewKey(ctx, "Task", "someTask", 0, nil)
query := datastore.NewQuery("Task").Filter("__key__ >", key)
// [END key_filter]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleQuery_invalidInequalitySortA() {
// [START inequality_sort_invalid_not_same]
query := datastore.NewQuery("Task").
Filter("Priority >", 3).
Order("Created")
// [END inequality_sort_invalid_not_same]
_ = query // The query is invalid.
}
func ExampleQuery_Filter_arrayEquality() {
// [START array_value_equality]
query := datastore.NewQuery("Task").
Filter("Tag =", "fun").
Filter("Tag =", "programming")
// [END array_value_equality]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleQuery_Filter_inequality() {
// [START inequality_range]
query := datastore.NewQuery("Task").
Filter("Created >", time.Date(1990, 1, 1, 0, 0, 0, 0, time.UTC)).
Filter("Created <", time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC))
// [END inequality_range]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleQuery_EventualConsistency() {
ctx := context.Background()
// [START eventual_consistent_query]
ancestor := datastore.NewKey(ctx, "TaskList", "default", 0, 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_Filter_invalidInequality() {
// [START inequality_invalid]
query := datastore.NewQuery("Task").
Filter("Created >", time.Date(1990, 1, 1, 0, 0, 0, 0, time.UTC)).
Filter("Priority >", 3)
// [END inequality_invalid]
_ = query // The query is invalid.
}
func ExampleQuery_Filter_arrayInequality() {
// [START array_value_inequality_range]
query := datastore.NewQuery("Task").
Filter("Tag >", "learn").
Filter("Tag <", "math")
// [END array_value_inequality_range]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleQuery_inequalitySort() {
// [START inequality_sort]
query := datastore.NewQuery("Task").
Filter("Priority >", 3).
Order("Priority").
Order("Created")
// [END inequality_sort]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func ExampleQuery_Filter_mixed() {
// [START equal_and_inequality_range]
query := datastore.NewQuery("Task").
Filter("Priority =", 4).
Filter("Done =", false).
Filter("Created >", time.Date(1990, 1, 1, 0, 0, 0, 0, time.UTC)).
Filter("Created <", time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC))
// [END equal_and_inequality_range]
_ = query // Use client.Run or client.GetAll to execute the query.
}
func queryVisits(ctx context.Context, limit int64) ([]*visit, error) {
// Print out previous visits.
q := datastore.NewQuery("Visit").
Order("-Timestamp").
Limit(10)
visits := make([]*visit, 0)
_, err := datastoreClient.GetAll(ctx, q, &visits)
return visits, err
}
func (ds *Datastore) IsNew(t, id string) bool {
dkey := datastore.NewKey(ds.ctx, t+"Entity", id, 0, nil)
keys, err := datastore.NewQuery(t+"Instruction").Ancestor(dkey).
Limit(1).KeysOnly().GetAll(ds.ctx, nil)
if err != nil {
return false
}
if len(keys) > 0 {
return false
}
return true
}
func ExampleQuery_KeysOnly() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
// [START keys_only_query]
query := datastore.NewQuery("Task").KeysOnly()
// [END keys_only_query]
// [START run_keys_only_query]
keys, err := client.GetAll(ctx, query, nil)
// [END run_keys_only_query]
_ = err // Make sure you check err.
_ = keys // Keys contains keys for all stored tasks.
}
func ExampleQuery_Distinct() {
// [START distinct_query]
query := datastore.NewQuery("Task").
Project("Priority", "PercentComplete").
Distinct().
Order("Type").Order("Priority")
// [END distinct_query]
_ = query // Use client.Run or client.GetAll to execute the query.
// [START distinct_on_query]
// DISTINCT ON not supported in Go API
// [END distinct_on_query]
}
func example2() {
// [START high_replication_data_definition_code]
g := Greeting{ /* ... */ }
key := datastore.NewIncompleteKey(ctx, "Greeting", guestbookKey(ctx))
// [END high_replication_data_definition_code]
// [START high_replication_query_code]
q := datastore.NewQuery("Greeting").Ancestor(guestbookKey(ctx)).Order("-Date").Limit(10)
// [END high_replication_query_code]
_ = g
_ = key
_ = q
}
func example() {
// [START master_slave_data_definition_code]
g := Greeting{ /* ... */ }
key := datastore.NewIncompleteKey(ctx, "Greeting", nil)
// [END master_slave_data_definition_code]
// [START master_slave_query_code]
q := datastore.NewQuery("Greeting").Order("-Date").Limit(10)
// [END master_slave_query_code]
_ = g
_ = key
_ = q
}
func (ds *Datastore) GetEntity(subject string) (reply []x.Instruction, rerr error) {
skey := datastore.NewKey(ds.ctx, ds.tablePrefix+"Entity", subject, 0, nil)
log.Infof("skey: %+v", skey)
client, err := datastore.NewClient(ds.ctx, ds.projectId)
if err != nil {
x.LogErr(log, err).Error("While creating client")
return reply, err
}
var dkeys []*datastore.Key
q := datastore.NewQuery(ds.tablePrefix + "Instruction").Ancestor(skey)
dkeys, rerr = client.GetAll(ds.ctx, q, &reply)
log.Debugf("Got num keys: %+v", len(dkeys))
return
}
func Example_metadataKinds() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
// [START kind_run_query]
query := datastore.NewQuery("__kind__").KeysOnly()
keys, err := client.GetAll(ctx, query, nil)
if err != nil {
log.Fatalf("client.GetAll: %v", err)
}
kinds := make([]string, 0, len(keys))
for _, k := range keys {
kinds = append(kinds, k.Name())
}
// [END kind_run_query]
}
// [START retrieve_entities]
// ListTasks returns all the tasks in ascending order of creation time.
func ListTasks(ctx context.Context, client *datastore.Client) ([]*Task, error) {
var tasks []*Task
// Create a query to fetch all queries, ordered by "created".
query := datastore.NewQuery("Task").Order("created")
keys, err := client.GetAll(ctx, query, &tasks)
if err != nil {
return nil, err
}
// Set the id field on each Task from the corresponding key.
for i, key := range keys {
tasks[i].id = key.ID()
}
return tasks, nil
}
func Example_metadataPropertiesForKind() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
// [START property_by_kind_run_query]
kindKey := datastore.NewKey(ctx, "__kind__", "Task", 0, 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.NewKey(ctx, "TaskList", "default", 0, 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.
}
// ListBooks returns a list of books, ordered by title.
func (db *datastoreDB) ListBooks() ([]*Book, error) {
ctx := context.Background()
books := make([]*Book, 0)
q := datastore.NewQuery("Book").
Order("Title")
keys, err := db.client.GetAll(ctx, q, &books)
if err != nil {
return nil, fmt.Errorf("datastoredb: could not list books: %v", err)
}
for i, k := range keys {
books[i].ID = k.ID()
}
return books, nil
}
func Example_metadataProperties() {
ctx := context.Background()
client, _ := datastore.NewClient(ctx, "my-proj")
// [START property_run_query]
query := datastore.NewQuery("__property__").KeysOnly()
keys, err := client.GetAll(ctx, query, nil)
if err != nil {
log.Fatalf("client.GetAll: %v", err)
}
props := make(map[string][]string) // Map from kind to slice of properties.
for _, k := range keys {
prop := k.Name()
kind := k.Parent().Name()
props[kind] = append(props[kind], prop)
}
// [END property_run_query]
}
func (fe *FeServiceImpl) isValidNewConfig(ctx context.Context, dsClient *datastore.Client, config *api.BiosphereCreationConfig) (bool, error) {
if config == nil {
return false, nil
}
if config.Name == "" || config.Nx <= 0 || config.Ny <= 0 {
return false, nil
}
// Name must be unique.
qSameName := datastore.NewQuery("BiosphereMeta").Filter("Name =", config.Name)
numSameName, err := dsClient.Count(ctx, qSameName)
if err != nil {
return false, err
}
if numSameName > 0 {
return false, nil
}
return true, nil
}
func (loc *INodeDBSSLocator) DeleteAll() ([]string, error) {
start := time.Now()
cli, err := loc.cfg.getClient(context.TODO())
if err != nil {
return nil, err
}
dstx, err := cli.NewTransaction(context.TODO(), datastore.Serializable)
if err != nil {
return nil, err
}
keys := make([]*datastore.Key, 0)
blobpaths := make([]string, 0)
q := datastore.NewQuery(kindINodeDBSS).Ancestor(loc.rootKey).Transaction(dstx)
it := cli.Run(context.TODO(), q)
for {
var e sslocentry
k, err := it.Next(&e)
if err != nil {
if err == datastore.Done {
break
}
dstx.Rollback()
return nil, err
}
keys = append(keys, k)
blobpaths = append(blobpaths, e.BlobPath)
}
logger.Debugf(sslog, "keys to delete: %v", keys)
if err := dstx.DeleteMulti(keys); err != nil {
dstx.Rollback()
return nil, err
}
if _, err := dstx.Commit(); err != nil {
return nil, err
}
logger.Infof(sslog, "DeleteAll() deleted %d entries. Took %s", len(keys), time.Since(start))
return blobpaths, nil
}
