春天云流 - gcp pubsub binder maxFetchSize？

Question

尝试使用来自 GCP pubsub 主题的 spring cloud gcp binder library 轮询消息。 来自streaming-vs-polled-input 的参考。 使用spring.cloud.stream.gcp.pubsub.default.consumer.maxFetchSize轮询一次获取 N 条消息（maxFetchSize 的值），但即使我设置了属性并将 maxFetchSize 设置为 2 或其他值。 我总是收到来自主题的 1 条消息，即使主题还有其他消息。 这里有人有其他想法吗？

• 春云版本：2021.0.3
• 谷歌 spring-cloud-gcp-dependencies 版本：3.3.0
• 爪哇：openjdk 11

# application.properties
spring.cloud.gcp.pubsub.project-id= 
spring.cloud.gcp.credentials.location= 
spring.cloud.stream.default-binder=pubsub
spring.cloud.stream.bindings.input.destination=iamatopic
spring.cloud.stream.bindings.input.content-type=text/plain;charset=UTF-8
spring.cloud.stream.gcp.pubsub.default.consumer.maxFetchSize=3

import org.springframework.cloud.stream.annotation.Input;
import org.springframework.cloud.stream.binder.PollableMessageSource;

public interface PollableSink {
    @Input("input")
    PollableMessageSource input();
}

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.ApplicationRunner;
import org.springframework.cloud.stream.annotation.EnableBinding;
import org.springframework.cloud.stream.binder.PollableMessageSource;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHandler;
import org.springframework.scheduling.annotation.Scheduled;

import com.google.cloud.spring.pubsub.support.AcknowledgeablePubsubMessage;
import com.google.cloud.spring.pubsub.support.GcpPubSubHeaders;

import lombok.extern.slf4j.Slf4j;

@Configuration
@EnableBinding(PollableSink.class)
@Slf4j
public class PollConfiguration {

    @Autowired
    PollableMessageSource destIn;

    PolledMessageHandler messageHandler = new PolledMessageHandler();

    @Scheduled(fixedRate = 5000)
    public void poller() {
        log.info("start polling ");
        destIn.poll(this.messageHandler, ParameterizedTypeReference.forType(String.class));
        log.info("end polling ");
    }

    static class PolledMessageHandler implements MessageHandler {
        @Override
        public void handleMessage(Message<?> message) {
            AcknowledgeablePubsubMessage ackableMessage = (AcknowledgeablePubsubMessage) message.getHeaders()
                    .get(GcpPubSubHeaders.ORIGINAL_MESSAGE);
            ackableMessage.ack();

            System.out.println("get payload : " + message.getPayload());
        }
    }
}

Answer 1

尝试设置spring.cloud.stream.poller.maxMessagesPerPoll值——在 Spring Cloud Stream 中默认为 1。

参考： https ://docs.spring.io/spring-cloud-stream/docs/current/reference/html/spring-cloud-stream.html#_polling_configuration_properties