v1 透過並行控制程序訂閱 (已淘汰)

(已淘汰) 透過並行控制程序訂閱

程式碼範例

Go

在試用這個範例之前，請先按照Go「Pub/Sub 快速入門導覽課程：使用用戶端程式庫」中的操作說明進行設定。 詳情請參閱 Pub/Sub Go API 參考說明文件。

如要驗證 Pub/Sub，請設定應用程式預設憑證。 詳情請參閱「為本機開發環境設定驗證」。

import (
	"context"
	"fmt"
	"io"
	"sync/atomic"
	"time"

	"cloud.google.com/go/pubsub"
)

func pullMsgsConcurrencyControl(w io.Writer, projectID, subID string) error {
	// projectID := "my-project-id"
	// subID := "my-sub"
	ctx := context.Background()
	client, err := pubsub.NewClient(ctx, projectID)
	if err != nil {
		return fmt.Errorf("pubsub.NewClient: %w", err)
	}
	defer client.Close()

	sub := client.Subscription(subID)
	// Must set ReceiveSettings.Synchronous to false (or leave as default) to enable
	// concurrency pulling of messages. Otherwise, NumGoroutines will be set to 1.
	sub.ReceiveSettings.Synchronous = false
	// NumGoroutines determines the number of goroutines sub.Receive will spawn to pull
	// messages.
	sub.ReceiveSettings.NumGoroutines = 16
	// MaxOutstandingMessages limits the number of concurrent handlers of messages.
	// In this case, up to 8 unacked messages can be handled concurrently.
	// Note, even in synchronous mode, messages pulled in a batch can still be handled
	// concurrently.
	sub.ReceiveSettings.MaxOutstandingMessages = 8

	// Receive messages for 10 seconds, which simplifies testing.
	// Comment this out in production, since `Receive` should
	// be used as a long running operation.
	ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
	defer cancel()

	var received int32

	// Receive blocks until the context is cancelled or an error occurs.
	err = sub.Receive(ctx, func(_ context.Context, msg *pubsub.Message) {
		atomic.AddInt32(&received, 1)
		msg.Ack()
	})
	if err != nil {
		return fmt.Errorf("sub.Receive returned error: %w", err)
	}
	fmt.Fprintf(w, "Received %d messages\n", received)

	return nil
}

Ruby

在試用這個範例之前，請先按照Ruby「Pub/Sub 快速入門導覽課程：使用用戶端程式庫」中的操作說明進行設定。 詳情請參閱 Pub/Sub Ruby API 參考說明文件。

如要驗證 Pub/Sub，請設定應用程式預設憑證。 詳情請參閱「為本機開發環境設定驗證」。

# subscription_id = "your-subscription-id"

pubsub = Google::Cloud::Pubsub.new

subscription = pubsub.subscription subscription_id
# Use 2 threads for streaming, 4 threads for executing callbacks and 2 threads
# for sending acknowledgements and/or delays
subscriber   = subscription.listen streams: 2, threads: {
  callback: 4,
  push:     2
} do |received_message|
  puts "Received message: #{received_message.data}"
  received_message.acknowledge!
end

subscriber.start
# Let the main thread sleep for 60 seconds so the thread for listening
# messages does not quit
sleep 60
subscriber.stop.wait!

後續步驟

如要搜尋及篩選其他 Google Cloud 產品的程式碼範例，請參閱Google Cloud 範例瀏覽器。