Google cloud platform 如何在发布/订阅主题上使用物联网遥测事件？

我读过谷歌云物联网API。我为Android编写了一个简单的应用程序。基于此，谷歌的。我的应用程序已成功连接到IoT平台，并已发送测试数据

我的申请代码

ConnectionParams connectionParams = new ConnectionParams.Builder()
            .setProjectId("my_pid")
            .setRegistry("my_reg", "my_server")
            .setDeviceId("my_device_name")
            .build();
IotCoreClient client = new IotCoreClient.Builder()
            .setConnectionParams(connectionParams)
            .setKeyPair(keys)
            .setTelemetryQueue(new LinkedTransferQueue<TelemetryEvent>())
            .build();

client.connect();

client.publishDeviceState("Test data\n".getBytes());

client.publishTelemetry(new TelemetryEvent("Sonata".getBytes(), null,TelemetryEvent.QOS_AT_LEAST_ONCE));

这段代码是可行的，但我在谷歌云平台上找不到“Sonata”数据，我不明白如何在发布/订阅主题上使用遥测事件

已更新

我找到了解决方案。第一步，我在主题中添加了订户。例子。Topic

projects/my project id/topics/firstTop

订户示例（fsub是订户名称）

projects/my project id/subscriptions/fsub

，我用java编写了简单的订户代码，并从Android的things设备发送了消息。我得到了遥测数据

这是java中的订户代码

import com.google.api.gax.core.CredentialsProvider;
import com.google.auth.Credentials;
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.pubsub.v1.AckReplyConsumer;
import com.google.cloud.pubsub.v1.MessageReceiver;
import com.google.cloud.pubsub.v1.Subscriber;
import com.google.common.collect.Lists;
import com.google.pubsub.v1.ProjectSubscriptionName;
import com.google.pubsub.v1.PubsubMessage;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;

public class SubscriberExample {
    private static final String PROJECT_ID = "my-project-id";
    private static final BlockingQueue<PubsubMessage> messages = new LinkedBlockingDeque<>();

    static class MessageReceiverExample implements MessageReceiver {
        @Override
        public void receiveMessage(PubsubMessage message, AckReplyConsumer consumer) {
            messages.offer(message);
            consumer.ack();
        }
    }

    public static void main(String... args) throws Exception {
        String subscriptionId = "YOUR_SUBSCRIBER_ID";
        ProjectSubscriptionName subscriptionName = ProjectSubscriptionName.of(PROJECT_ID, subscriptionId);
        Subscriber subscriber = null;
        try {
            GoogleCredentials credentials = GoogleCredentials
                    .fromStream(new FileInputStream("~/google_cloud_pubsub-Project-0b66ab8c5060.json")) // you can get here https://cloud.google.com/docs/authentication/getting-started
                    .createScoped(Lists.newArrayList("https://www.googleapis.com/auth/cloud-platform"));
            subscriber = Subscriber.newBuilder(subscriptionName, new MessageReceiverExample())
                    .setCredentialsProvider(new CredentialsProvider() {
                        @Override
                        public Credentials getCredentials() throws IOException {
                            return credentials;
                        }
                    }).build();
            subscriber.startAsync().awaitRunning();
            while (true) {
                PubsubMessage message = messages.take();
                System.out.println("Message Id: " + message.getMessageId());
                System.out.println("Data: " + message.getData().toStringUtf8());
            }
        } finally {
            if (subscriber != null) {
                subscriber.stopAsync();
            }
        }
    }
}

import com.google.api.gax.core.CredentialsProvider；
导入com.google.auth.Credentials；
导入com.google.auth.oauth2.GoogleCredentials；
导入com.google.cloud.pubsub.v1.AckReplyConsumer；
导入com.google.cloud.pubsub.v1.MessageReceiver；
导入com.google.cloud.pubsub.v1.Subscriber；
导入com.google.common.collect.list；
导入com.google.pubsub.v1.ProjectSubscriptionName；
导入com.google.pubsub.v1.PubsubMessage；
导入java.io.FileInputStream；
导入java.io.IOException；
导入java.util.concurrent.BlockingQueue；
导入java.util.concurrent.LinkedBlockingDeque；
公共类订阅示例{
私有静态最终字符串项目\u ID=“我的项目ID”；
private static final BlockingQueue messages=new LinkedBlockingDeque（）；
静态类MessageReceiver示例实现MessageReceiver{
@凌驾
public void receiveMessage（PubsubMessage消息，AckReplyConsumer消费者）{
消息。提供（消息）；
consumer.ack（）；
}
}
公共静态void main（字符串…参数）引发异常{
String subscriptionId=“您的订户ID”；
ProjectSubscriptionName subscriptionName=ProjectSubscriptionName.of（项目ID，subscriptionId）；
订户=null；
试一试{
GoogleCredentials=GoogleCredentials
.fromStream（新文件输入流（“~/google\u cloud\u pubsub-Project-0b66ab8c5060.json”）//您可以在这里获得https://cloud.google.com/docs/authentication/getting-started
.createScope（列表.newArrayList（“https://www.googleapis.com/auth/cloud-platform"));
subscriber=subscriber.newBuilder（subscriptionName，newmessagereceiverexample（））
.setCredentialsProvider（新的CredentialsProvider（）{
@凌驾
公共凭据getCredentials（）引发IOException{
返回凭证；
}
}).build（）；
subscriber.startAsync（）.awaitRunning（）；
while（true）{
PubsubMessage=messages.take（）；
System.out.println（“消息Id:+Message.getMessageId（））；
System.out.println（“数据：”+message.getData（）.toStringUtf8（））；
}
}最后{
if（订户！=null）{
subscriber.stopAsync（）；
}
}
}
}

首先要检查它是否正常工作，并且连接是否真的要连接到您的项目，最简单的方法是查看项目的Google云平台控制台，在IoT核心部分（IoT核心->注册表->设备）的设备页面上，有一个“配置和状态历史记录”选项卡，您应该在那里看到“测试数据”（如publishDeviceState调用所设置的）。这应该可以确认至少其他一切都按照预期工作

假设是这样的话，现在您需要查看发布/订阅文档，开始了解如何使用发布/订阅。这是主要的文档页面。我的建议是查看作为快速启动和运行的地方。根据您想要做的，这可能也是一个很好的选择

这些产品中的每一个都会根据发布到云发布/订阅中的消息触发。因此，只要您调用“publishTelemetry”，它就会将遥测发送到IoT Core，IoT Core会在您创建消息时将消息发布到IoT Core注册表中指定的发布/订阅主题中。然后触发的产品（GCF和数据流）接收可从中获取遥测数据的发布/订阅对象。文档中有关于如何执行此操作的示例

import com.google.api.gax.core.CredentialsProvider;
import com.google.auth.Credentials;
import com.google.auth.oauth2.GoogleCredentials;
import com.google.cloud.pubsub.v1.AckReplyConsumer;
import com.google.cloud.pubsub.v1.MessageReceiver;
import com.google.cloud.pubsub.v1.Subscriber;
import com.google.common.collect.Lists;
import com.google.pubsub.v1.ProjectSubscriptionName;
import com.google.pubsub.v1.PubsubMessage;

import java.io.FileInputStream;
import java.io.IOException;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingDeque;

public class SubscriberExample {
    private static final String PROJECT_ID = "my-project-id";
    private static final BlockingQueue<PubsubMessage> messages = new LinkedBlockingDeque<>();

    static class MessageReceiverExample implements MessageReceiver {
        @Override
        public void receiveMessage(PubsubMessage message, AckReplyConsumer consumer) {
            messages.offer(message);
            consumer.ack();
        }
    }

    public static void main(String... args) throws Exception {
        String subscriptionId = "YOUR_SUBSCRIBER_ID";
        ProjectSubscriptionName subscriptionName = ProjectSubscriptionName.of(PROJECT_ID, subscriptionId);
        Subscriber subscriber = null;
        try {
            GoogleCredentials credentials = GoogleCredentials
                    .fromStream(new FileInputStream("~/google_cloud_pubsub-Project-0b66ab8c5060.json")) // you can get here https://cloud.google.com/docs/authentication/getting-started
                    .createScoped(Lists.newArrayList("https://www.googleapis.com/auth/cloud-platform"));
            subscriber = Subscriber.newBuilder(subscriptionName, new MessageReceiverExample())
                    .setCredentialsProvider(new CredentialsProvider() {
                        @Override
                        public Credentials getCredentials() throws IOException {
                            return credentials;
                        }
                    }).build();
            subscriber.startAsync().awaitRunning();
            while (true) {
                PubsubMessage message = messages.take();
                System.out.println("Message Id: " + message.getMessageId());
                System.out.println("Data: " + message.getData().toStringUtf8());
            }
        } finally {
            if (subscriber != null) {
                subscriber.stopAsync();
            }
        }
    }
}