Utilizza cloud.google.com/go/bigquery/storage/managedwriter per aggiungere dati utilizzando un messaggio definito in modo statico.
Per saperne di più
Per la documentazione dettagliata che include questo esempio di codice, consulta quanto segue:
- Caricare i dati in batch utilizzando l'API Storage Write
- Caricare i dati in batch utilizzando l'API Storage Write
Esempio di codice
Go
Prima di provare questo esempio, segui le istruzioni di configurazione di Go nella guida rapida di BigQuery che utilizza le librerie client. Per ulteriori informazioni, consulta la documentazione di riferimento per le API GoBigQuery.
Per eseguire l'autenticazione in BigQuery, configura le Credenziali predefinite dell'applicazione. Per saperne di più, consulta Configurare l'autenticazione per un ambiente di sviluppo locale.
import (
"context"
"fmt"
"io"
"math/rand"
"time"
"cloud.google.com/go/bigquery/storage/managedwriter"
"cloud.google.com/go/bigquery/storage/managedwriter/adapt"
"github.com/GoogleCloudPlatform/golang-samples/bigquery/snippets/managedwriter/exampleproto"
storagepb "google.golang.org/genproto/googleapis/cloud/bigquery/storage/v1"
"google.golang.org/protobuf/proto"
)
// generateExampleMessages generates a slice of serialized protobuf messages using a statically defined
// and compiled protocol buffer file, and returns the binary serialized representation.
func generateExampleMessages(numMessages int) ([][]byte, error) {
msgs := make([][]byte, numMessages)
for i := 0; i < numMessages; i++ {
random := rand.New(rand.NewSource(time.Now().UnixNano()))
// Our example data embeds an array of structs, so we'll construct that first.
sList := make([]*exampleproto.SampleStruct, 5)
for i := 0; i < int(random.Int63n(5)+1); i++ {
sList[i] = &exampleproto.SampleStruct{
SubIntCol: proto.Int64(random.Int63()),
}
}
m := &exampleproto.SampleData{
BoolCol: proto.Bool(true),
BytesCol: []byte("some bytes"),
Float64Col: proto.Float64(3.14),
Int64Col: proto.Int64(123),
StringCol: proto.String("example string value"),
// These types require special encoding/formatting to transmit.
// DATE values are number of days since the Unix epoch.
DateCol: proto.Int32(int32(time.Now().UnixNano() / 86400000000000)),
// DATETIME uses the literal format.
DatetimeCol: proto.String("2022-01-01 12:13:14.000000"),
// GEOGRAPHY uses Well-Known-Text (WKT) format.
GeographyCol: proto.String("POINT(-122.350220 47.649154)"),
// NUMERIC and BIGNUMERIC can be passed as string, or more efficiently
// using a packed byte representation.
NumericCol: proto.String("99999999999999999999999999999.999999999"),
BignumericCol: proto.String("578960446186580977117854925043439539266.34992332820282019728792003956564819967"),
// TIME also uses literal format.
TimeCol: proto.String("12:13:14.000000"),
// TIMESTAMP uses microseconds since Unix epoch.
TimestampCol: proto.Int64(time.Now().UnixNano() / 1000),
// Int64List is an array of INT64 types.
Int64List: []int64{2, 4, 6, 8},
// This is a required field, and thus must be present.
RowNum: proto.Int64(23),
// StructCol is a single nested message.
StructCol: &exampleproto.SampleStruct{
SubIntCol: proto.Int64(random.Int63()),
},
// StructList is a repeated array of a nested message.
StructList: sList,
}
b, err := proto.Marshal(m)
if err != nil {
return nil, fmt.Errorf("error generating message %d: %w", i, err)
}
msgs[i] = b
}
return msgs, nil
}
// appendToPendingStream demonstrates using the managedwriter package to write some example data
// to a pending stream, and then committing it to a table.
func appendToPendingStream(w io.Writer, projectID, datasetID, tableID string) error {
// projectID := "myproject"
// datasetID := "mydataset"
// tableID := "mytable"
ctx := context.Background()
// Instantiate a managedwriter client to handle interactions with the service.
client, err := managedwriter.NewClient(ctx, projectID)
if err != nil {
return fmt.Errorf("managedwriter.NewClient: %w", err)
}
// Close the client when we exit the function.
defer client.Close()
// Create a new pending stream. We'll use the stream name to construct a writer.
pendingStream, err := client.CreateWriteStream(ctx, &storagepb.CreateWriteStreamRequest{
Parent: fmt.Sprintf("projects/%s/datasets/%s/tables/%s", projectID, datasetID, tableID),
WriteStream: &storagepb.WriteStream{
Type: storagepb.WriteStream_PENDING,
},
})
if err != nil {
return fmt.Errorf("CreateWriteStream: %w", err)
}
// We need to communicate the descriptor of the protocol buffer message we're using, which
// is analagous to the "schema" for the message. Both SampleData and SampleStruct are
// two distinct messages in the compiled proto file, so we'll use adapt.NormalizeDescriptor
// to unify them into a single self-contained descriptor representation.
m := &exampleproto.SampleData{}
descriptorProto, err := adapt.NormalizeDescriptor(m.ProtoReflect().Descriptor())
if err != nil {
return fmt.Errorf("NormalizeDescriptor: %w", err)
}
// Instantiate a ManagedStream, which manages low level details like connection state and provides
// additional features like a future-like callback for appends, etc. NewManagedStream can also create
// the stream on your behalf, but in this example we're being explicit about stream creation.
managedStream, err := client.NewManagedStream(ctx, managedwriter.WithStreamName(pendingStream.GetName()),
managedwriter.WithSchemaDescriptor(descriptorProto))
if err != nil {
return fmt.Errorf("NewManagedStream: %w", err)
}
defer managedStream.Close()
// First, we'll append a single row.
rows, err := generateExampleMessages(1)
if err != nil {
return fmt.Errorf("generateExampleMessages: %w", err)
}
// We'll keep track of the current offset in the stream with curOffset.
var curOffset int64
// We can append data asyncronously, so we'll check our appends at the end.
var results []*managedwriter.AppendResult
result, err := managedStream.AppendRows(ctx, rows, managedwriter.WithOffset(0))
if err != nil {
return fmt.Errorf("AppendRows first call error: %w", err)
}
results = append(results, result)
// Advance our current offset.
curOffset = curOffset + 1
// This time, we'll append three more rows in a single request.
rows, err = generateExampleMessages(3)
if err != nil {
return fmt.Errorf("generateExampleMessages: %w", err)
}
result, err = managedStream.AppendRows(ctx, rows, managedwriter.WithOffset(curOffset))
if err != nil {
return fmt.Errorf("AppendRows second call error: %w", err)
}
results = append(results, result)
// Advance our offset again.
curOffset = curOffset + 3
// Finally, we'll append two more rows.
rows, err = generateExampleMessages(2)
if err != nil {
return fmt.Errorf("generateExampleMessages: %w", err)
}
result, err = managedStream.AppendRows(ctx, rows, managedwriter.WithOffset(curOffset))
if err != nil {
return fmt.Errorf("AppendRows third call error: %w", err)
}
results = append(results, result)
// Now, we'll check that our batch of three appends all completed successfully.
// Monitoring the results could also be done out of band via a goroutine.
for k, v := range results {
// GetResult blocks until we receive a response from the API.
recvOffset, err := v.GetResult(ctx)
if err != nil {
return fmt.Errorf("append %d returned error: %w", k, err)
}
fmt.Fprintf(w, "Successfully appended data at offset %d.\n", recvOffset)
}
// We're now done appending to this stream. We now mark pending stream finalized, which blocks
// further appends.
rowCount, err := managedStream.Finalize(ctx)
if err != nil {
return fmt.Errorf("error during Finalize: %w", err)
}
fmt.Fprintf(w, "Stream %s finalized with %d rows.\n", managedStream.StreamName(), rowCount)
// To commit the data to the table, we need to run a batch commit. You can commit several streams
// atomically as a group, but in this instance we'll only commit the single stream.
req := &storagepb.BatchCommitWriteStreamsRequest{
Parent: managedwriter.TableParentFromStreamName(managedStream.StreamName()),
WriteStreams: []string{managedStream.StreamName()},
}
resp, err := client.BatchCommitWriteStreams(ctx, req)
if err != nil {
return fmt.Errorf("client.BatchCommit: %w", err)
}
if len(resp.GetStreamErrors()) > 0 {
return fmt.Errorf("stream errors present: %v", resp.GetStreamErrors())
}
fmt.Fprintf(w, "Table data committed at %s\n", resp.GetCommitTime().AsTime().Format(time.RFC3339Nano))
return nil
}
Passaggi successivi
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