CloudEvents SDK

本章节介绍使用开源的CloudEvents Java SDK发布事件。

前提条件

获取并安装IntelliJ IDEA，如果未安装，请至IntelliJ IDEA官方网站下载。

在pom.xml中加入依赖。如何在Java环境中集成API请求签名的SDK请参考AK/SK签名认证操作指导。

<dependency>
            <groupId>io.cloudevents</groupId>
            <artifactId>cloudevents-json-jackson</artifactId>
            <version>${cloudevents.version}</version>
</dependency>
<dependency>
            <groupId>com.huawei.apigateway</groupId>
            <artifactId>java-sdk-core</artifactId>
            <version>3.1.2</version>
</dependency>

“cloudevents.version”使用最新版本2.2.0。

发布事件

发布事件的示例代码如下（以下加粗内容需要请根据实际情况替换）：

import com.alibaba.fastjson.JSONObject;
import io.cloudevents.CloudEvent;
import io.cloudevents.core.builder.CloudEventBuilder;
import io.cloudevents.core.provider.EventFormatProvider;
import io.cloudevents.jackson.JsonFormat;
import lombok.extern.slf4j.Slf4j;
import org.apache.http.Header;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.conn.ssl.NoopHostnameVerifier;
import org.apache.http.conn.ssl.SSLConnectionSocketFactory;
import org.apache.http.conn.ssl.TrustSelfSignedStrategy;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.ssl.SSLContexts;
import org.apache.http.util.EntityUtils;

import java.net.URI;
import java.time.LocalDateTime;
import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;
import java.util.*;
import java.util.stream.Collectors;

@Slf4j
public class PublishService {
    private static final String NAME = "l******";

    private static final String PASSWORD = "******";

    private static final String DOMAIN_NAME = "paa******01";

    private static final String PROJECT_ID = "c5******f";

    private static final String CHANNEL_ID = "ff******3";

    private static final String ENDPOINT = "events.cn-north-4.myhuaweicloud.com";

    private static final String URL = "https://" + ENDPOINT + "/v1/" + PROJECT_ID + "/channels/" + CHANNEL_ID + "/events";

    private static final String SOURCE = "test_source";

    private static final String IAM_ENDPOINT = "iam.cn-north-4.myhuaweicloud.com";

    private static final String IAM_ADDRESS = "https://" + IAM_ENDPOINT + "/v3/auth/tokens";

    private static final String IAM_BODY = "{\"auth\": {\"identity\": {\"methods\": [\"password\"],\"password\": {\"user\": " +
            "{\"name\": \"" + NAME + "\",\"password\": \"" + PASSWORD + "\",\"domain\": {\"name\": \"" + DOMAIN_NAME + "\"}}}}," +
            "\"scope\": {\"project\": {\"id\": \"" + PROJECT_ID + "\"}}}}";

    private static final Map<String, String> tokenCache = new HashMap<>();

    private static final Map<String, LocalDateTime> expireTimeCache = new HashMap<>();

    public static void main(String[] args) {
        try {
            PublishService publishService = new PublishService();
            CloudEvent cloudEvent = publishService.buildCloudEvent(SOURCE);
            publishService.publish(cloudEvent);
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }
	
    /**
     * 获取token
     *
     * @param userName IAM账户用户名
     * @param domainName IAM账户domain用户名
     * @throws Exception
     */
    public String getToken(String userName, String domainName) throws Exception {
        synchronized(expireTimeCache) {
            String cacheKey = domainName + userName;
            LocalDateTime expireTime = expireTimeCache.get(cacheKey);
            if (expireTime != null && tokenCache.get(cacheKey) != null) {
                LocalDateTime curTime = LocalDateTime.now().minusMinutes(5);
                if (curTime.isBefore(expireTime)) {
                    return tokenCache.get(cacheKey);
                }
            }
            Map<String, String> headers = new HashMap<>();
            HttpResponse postResponse = getPostResponse(IAM_ADDRESS, headers, IAM_BODY);

            Header[] allHeaders = postResponse.getAllHeaders();
            HttpEntity entity = postResponse.getEntity();
            if (entity != null) {
                String entityString = EntityUtils.toString(entity, "UTF-8");
                JSONObject jsonObject = JSONObject.parseObject(entityString);
                DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss");
                String[] split = jsonObject.getJSONObject("token").getString("expires_at").split("\\.");
                expireTimeCache.put(cacheKey, LocalDateTime.parse(split[0], dateTimeFormatter));
            }

            List<Header> collect = Arrays.stream(allHeaders).filter(header -> header.getName().equals("X-Subject-Token")).collect(Collectors.toList());
            String token = collect.get(0).getValue();
            tokenCache.put(cacheKey, token);
            return token;
        }
    }

    /**
     * 推送CloudEvents事件到EG-engine
     *
     * @param cloudEvent
     * @throws Exception
     */
    public void publish(CloudEvent cloudEvent) throws Exception {
        String body = buildBody(cloudEvent);
        Map<String, String> headers = new HashMap<>();
        headers.put("X-Auth-Token", getToken(DOMAIN_NAME, NAME));

        HttpEntity resEntity = getPostResponse(URL, headers, body).getEntity();
        if (resEntity != null) {
            System.out.println(System.getProperty("line.separator") + EntityUtils.toString(resEntity, "UTF-8"));
        }
    }

    /**
     * 构建CloudEvents实体
     *
     * @param source 事件源名称
     * @return CloudEvents实体
     */

    private CloudEvent buildCloudEvent(String source) {
        io.cloudevents.core.v1.CloudEventBuilder cloudEventBuilder = CloudEventBuilder.v1()
                .withId(UUID.randomUUID().toString())
                .withSource(URI.create(source))
                .withType(JsonFormat.CONTENT_TYPE)
                .withTime(OffsetDateTime.now());
        return cloudEventBuilder.build();
    }

    private static String buildBody(CloudEvent cloudEvent) {
        JsonFormat jsonFormat = ((JsonFormat) Objects.requireNonNull(EventFormatProvider.getInstance()
                .resolveFormat("application/cloudevents+json"))).withForceNonJsonDataToString();
        EventFormatProvider.getInstance().registerFormat(jsonFormat);
        return "{\"events\": [" + new String(jsonFormat.serialize(cloudEvent)) + "]}";
    }

    /**
     * 使用指定的headers和 body进行https请求
     *
     * @param headers 请求headers
     * @param body    请求体
     * @return
     * @throws Exception
     */
    private HttpResponse getPostResponse(String url, Map<String, String> headers, String body) throws Exception {
        CloseableHttpClient client = null;
        SSLConnectionSocketFactory scsf = new SSLConnectionSocketFactory(
                SSLContexts.custom().loadTrustMaterial(null, new TrustSelfSignedStrategy()).build(),
                NoopHostnameVerifier.INSTANCE);
        client = HttpClients.custom().setSSLSocketFactory(scsf).build();
        HttpPost httpPost = new HttpPost(url);

        headers.forEach(httpPost::addHeader);
        httpPost.addHeader("Content-Type", "application/json");
        httpPost.setEntity(new StringEntity(body, "UTF-8"));

        return client.execute(httpPost);
    }
}

参数说明：

NAME：IAM用户名。
PASSWORD：IAM 用户密码。
DOMAIN_NAME：IAM domain用户名。
IAM_ENDPOINT：IAM的终端节点，您可以从地区和终端节点中查询服务的终端节点。
PROJECT_ID：即项目ID，参考API凭证，获取项目ID。
CHANNEL_ID：参考收集信息，获取通道ID。
ENDPOINT：事件网格访问端点，如“华北-北京四”区域，公网访问端点值为“events.cn-north-4.myhuaweicloud.com”。
SOURCE：即事件源名称，参考收集信息，获取Filter中的values值。

上一篇：收集信息

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CloudEvents SDK

前提条件

发布事件

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