云 Pub/Sub 是否与云 Dataflow 的订阅传递配合使用？

是的，云 Pub/Sub可以与云 Dataflow的订阅传递配合使用。下面是一个使用Java代码示例：

1. 创建一个Pub/Sub主题和订阅：

import com.google.cloud.pubsub.v1.TopicAdminClient;
import com.google.cloud.pubsub.v1.TopicName;
import com.google.pubsub.v1.ProjectTopicName;
import com.google.pubsub.v1.Topic;

String projectId = "your-project-id";
String topicId = "your-topic-id";
String subscriptionId = "your-subscription-id";

// 创建主题
ProjectTopicName topicName = ProjectTopicName.of(projectId, topicId);
TopicAdminClient topicAdminClient = TopicAdminClient.create();
Topic topic = topicAdminClient.createTopic(topicName);

// 创建订阅
TopicName topicName = TopicName.of(projectId, topicId);
SubscriptionAdminClient subscriptionAdminClient = SubscriptionAdminClient.create();
ProjectSubscriptionName subscriptionName = ProjectSubscriptionName.of(projectId, subscriptionId);
Subscription subscription = subscriptionAdminClient.createSubscription(subscriptionName, topicName, PushConfig.getDefaultInstance(), 0);

2. 创建一个Dataflow管道，将Pub/Sub订阅传递给Dataflow：

import com.google.cloud.dataflow.sdk.Pipeline;
import com.google.cloud.dataflow.sdk.io.PubsubIO;
import com.google.cloud.dataflow.sdk.options.DataflowPipelineOptions;
import com.google.cloud.dataflow.sdk.options.PipelineOptionsFactory;
import com.google.cloud.dataflow.sdk.transforms.DoFn;
import com.google.cloud.dataflow.sdk.transforms.ParDo;
import com.google.cloud.dataflow.sdk.values.PCollection;
import com.google.pubsub.v1.PubsubMessage;
import com.google.protobuf.ByteString;

String projectId = "your-project-id";
String topicId = "your-topic-id";
String subscriptionId = "your-subscription-id";

// 创建Dataflow管道选项
DataflowPipelineOptions options = PipelineOptionsFactory.fromArgs(args).as(DataflowPipelineOptions.class);

// 设置管道的项目ID
options.setProject(projectId);

// 创建Dataflow管道
Pipeline pipeline = Pipeline.create(options);

// 从Pub/Sub订阅中读取消息
PCollection<PubsubMessage> messages = pipeline.apply(PubsubIO.Read.topic(String.format("projects/%s/topics/%s", projectId, topicId)));

// 对消息进行处理
PCollection<String> messageStrings = messages.apply(ParDo.of(new DoFn<PubsubMessage, String>() {
  @ProcessElement
  public void processElement(ProcessContext c) {
    ByteString payload = c.element().getPayload();
    String messageString = payload.toStringUtf8();
    c.output(messageString);
  }
}));

// 打印处理后的消息
messageStrings.apply(ParDo.of(new DoFn<String, Void>() {
  @ProcessElement
  public void processElement(ProcessContext c) {
    System.out.println(c.element());
  }
}));

// 运行Dataflow管道
pipeline.run();

这个例子创建了一个Pub/Sub主题和订阅，并将订阅传递给Dataflow管道。管道从订阅中读取消息，然后对消息进行处理并打印出来。你可以根据自己的需求修改和扩展这个示例。