dubbo中MetadataReportService的原理及作用

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序

本文主要研究一下dubbo的MetadataReportService

MetadataReportService

dubbo-2.7.2/dubbo-metadata-report/dubbo-metadata-report-api/src/main/java/org/apache/dubbo/metadata/integration/MetadataReportService.java

public class MetadataReportService {

    protected final Logger logger = LoggerFactory.getLogger(getClass());

    private static volatile MetadataReportService metadataReportService;
    private static Object lock = new Object();

    private MetadataReportFactory metadataReportFactory = ExtensionLoader.getExtensionLoader(MetadataReportFactory.class).getAdaptiveExtension();
    MetadataReport metadataReport;
    URL metadataReportUrl;

    MetadataReportService(URL metadataReportURL) {
        if (METADATA_REPORT_KEY.equals(metadataReportURL.getProtocol())) {
            String protocol = metadataReportURL.getParameter(METADATA_REPORT_KEY, DEFAULT_DIRECTORY);
            metadataReportURL = URLBuilder.from(metadataReportURL)
                    .setProtocol(protocol)
                    .removeParameter(METADATA_REPORT_KEY)
                    .build();
        }
        this.metadataReportUrl = metadataReportURL;
        metadataReport = metadataReportFactory.getMetadataReport(this.metadataReportUrl);

    }


    public static MetadataReportService instance(Supplier metadataReportUrl) {
        if (metadataReportService == null) {
            synchronized (lock) {
                if (metadataReportService == null) {
                    URL metadataReportURLTmp = metadataReportUrl.get();
                    if (metadataReportURLTmp == null) {
                        return null;
                    }
                    metadataReportService = new MetadataReportService(metadataReportURLTmp);
                }
            }
        }
        return metadataReportService;
    }

    public void publishProvider(URL providerUrl) throws RpcException {
        //first add into the list
        // remove the individul param
        providerUrl = providerUrl.removeParameters(PID_KEY, TIMESTAMP_KEY, Constants.BIND_IP_KEY, Constants.BIND_PORT_KEY, TIMESTAMP_KEY);

        try {
            String interfaceName = providerUrl.getParameter(INTERFACE_KEY);
            if (StringUtils.isNotEmpty(interfaceName)) {
                Class interfaceClass = Class.forName(interfaceName);
                FullServiceDefinition fullServiceDefinition = ServiceDefinitionBuilder.buildFullDefinition(interfaceClass, providerUrl.getParameters());
                metadataReport.storeProviderMetadata(new MetadataIdentifier(providerUrl.getServiceInterface(),
                        providerUrl.getParameter(VERSION_KEY), providerUrl.getParameter(GROUP_KEY),
                        PROVIDER_SIDE, providerUrl.getParameter(APPLICATION_KEY)), fullServiceDefinition);
                return;
            }
            logger.error("publishProvider interfaceName is empty . providerUrl: " + providerUrl.toFullString());
        } catch (ClassNotFoundException e) {
            //ignore error
            logger.error("publishProvider getServiceDescriptor error. providerUrl: " + providerUrl.toFullString(), e);
        }
    }

    public void publishConsumer(URL consumerURL) throws RpcException {
        consumerURL = consumerURL.removeParameters(PID_KEY, TIMESTAMP_KEY, Constants.BIND_IP_KEY, Constants.BIND_PORT_KEY, TIMESTAMP_KEY);
        metadataReport.storeConsumerMetadata(new MetadataIdentifier(consumerURL.getServiceInterface(),
                consumerURL.getParameter(VERSION_KEY), consumerURL.getParameter(GROUP_KEY), CONSUMER_SIDE,
                consumerURL.getParameter(APPLICATION_KEY)), consumerURL.getParameters());
    }

}

• MetadataReportService的构造器通过metadataReportURL来获取对应的MetadataReport；它定义了publishProvider方法主要是执行metadataReport.storeProviderMetadata方法；还定义了publishConsumer方法主要是执行metadataReport.storeConsumerMetadata方法；同时还提供了一个静态方法使用双重检锁的单例模式创建MetadataReportService

实例

dubbo-2.7.2/dubbo-metadata-report/dubbo-metadata-report-api/src/test/java/org/apache/dubbo/metadata/integration/MetadataReportServiceTest.java

public class MetadataReportServiceTest {
    URL url = URL.valueOf("JTest://" + NetUtils.getLocalAddress().getHostName() + ":4444/org.apache.dubbo.TestService?version=1.0.0&application=vic");
    MetadataReportService metadataReportService1;

    @BeforeEach
    public void before() {
        metadataReportService1 = MetadataReportService.instance(() -> url);
    }

    @Test
    public void testInstance() {

        MetadataReportService metadataReportService2 = MetadataReportService.instance(new Supplier() {
            @Override
            public URL get() {
                return url;
            }
        });
        Assertions.assertSame(metadataReportService1, metadataReportService2);
        Assertions.assertEquals(metadataReportService1.metadataReportUrl, url);
    }

    @Test
    public void testPublishProviderNoInterfaceName() {


        URL publishUrl = URL.valueOf("dubbo://" + NetUtils.getLocalAddress().getHostName() + ":4444/org.apache.dubbo.TestService?version=1.0.0&application=vicpubprovder&side=provider");
        metadataReportService1.publishProvider(publishUrl);

        Assertions.assertTrue(metadataReportService1.metadataReport instanceof JTestMetadataReport4Test);

        JTestMetadataReport4Test jTestMetadataReport4Test = (JTestMetadataReport4Test) metadataReportService1.metadataReport;
        Assertions.assertTrue(!jTestMetadataReport4Test.store.containsKey(JTestMetadataReport4Test.getProviderKey(publishUrl)));

    }

    @Test
    public void testPublishProviderWrongInterface() {

        URL publishUrl = URL.valueOf("dubbo://" + NetUtils.getLocalAddress().getHostName() + ":4444/org.apache.dubbo.TestService?version=1.0.0&application=vicpu&interface=ccc&side=provider");
        metadataReportService1.publishProvider(publishUrl);

        Assertions.assertTrue(metadataReportService1.metadataReport instanceof JTestMetadataReport4Test);

        JTestMetadataReport4Test jTestMetadataReport4Test = (JTestMetadataReport4Test) metadataReportService1.metadataReport;
        Assertions.assertTrue(!jTestMetadataReport4Test.store.containsKey(JTestMetadataReport4Test.getProviderKey(publishUrl)));

    }

    @Test
    public void testPublishProviderContainInterface() throws InterruptedException {

        URL publishUrl = URL.valueOf("dubbo://" + NetUtils.getLocalAddress().getHostName() + ":4444/org.apache.dubbo.TestService?version=1.0.3&application=vicpubp&interface=org.apache.dubbo.metadata.integration.InterfaceNameTestService&side=provider");
        metadataReportService1.publishProvider(publishUrl);
        Thread.sleep(300);

        Assertions.assertTrue(metadataReportService1.metadataReport instanceof JTestMetadataReport4Test);

        JTestMetadataReport4Test jTestMetadataReport4Test = (JTestMetadataReport4Test) metadataReportService1.metadataReport;
        Assertions.assertTrue(jTestMetadataReport4Test.store.containsKey(JTestMetadataReport4Test.getProviderKey(publishUrl)));

        String value = jTestMetadataReport4Test.store.get(JTestMetadataReport4Test.getProviderKey(publishUrl));
        FullServiceDefinition fullServiceDefinition = toServiceDefinition(value);
        Map map = fullServiceDefinition.getParameters();
        Assertions.assertEquals(map.get("application"), "vicpubp");
        Assertions.assertEquals(map.get("version"), "1.0.3");
        Assertions.assertEquals(map.get("interface"), "org.apache.dubbo.metadata.integration.InterfaceNameTestService");
    }

    @Test
    public void testPublishConsumer() throws InterruptedException {

        URL publishUrl = URL.valueOf("dubbo://" + NetUtils.getLocalAddress().getHostName() + ":4444/org.apache.dubbo.TestService?version=1.0.x&application=vicpubconsumer&side=consumer");
        metadataReportService1.publishConsumer(publishUrl);
        Thread.sleep(300);

        Assertions.assertTrue(metadataReportService1.metadataReport instanceof JTestMetadataReport4Test);

        JTestMetadataReport4Test jTestMetadataReport4Test = (JTestMetadataReport4Test) metadataReportService1.metadataReport;
        Assertions.assertTrue(jTestMetadataReport4Test.store.containsKey(JTestMetadataReport4Test.getConsumerKey(publishUrl)));

        String value = jTestMetadataReport4Test.store.get(JTestMetadataReport4Test.getConsumerKey(publishUrl));
        Gson gson = new Gson();
        Map map = gson.fromJson(value, Map.class);
        Assertions.assertEquals(map.get("application"), "vicpubconsumer");
        Assertions.assertEquals(map.get("version"), "1.0.x");

    }

    private FullServiceDefinition toServiceDefinition(String urlQuery) {
        Gson gson = new Gson();
        return gson.fromJson(urlQuery, FullServiceDefinition.class);
    }

}

• 这里的testInstance方法验证了单例模式；之后对publishProvider验证了noInterfaceName、wrongInterface、containInterface的场景；最后验证了publishConsumer

小结

MetadataReportService的构造器通过metadataReportURL来获取对应的MetadataReport；它定义了publishProvider方法主要是执行metadataReport.storeProviderMetadata方法；还定义了publishConsumer方法主要是执行metadataReport.storeConsumerMetadata方法；同时还提供了一个静态方法使用双重检锁的单例模式创建MetadataReportService

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