Metadata Center Extension

Metadata Center Extension

Design Purpose

Please refer to the Metadata Center Manual

Extension Interfaces

• org.apache.dubbo.metadata.store.MetadataReportFactory
• org.apache.dubbo.metadata.store.MetadataReport

Known Extensions

Implementation Principles

SPI Definition

Reference: org.apache.dubbo.metadata.store.MetadataReportFactory, org.apache.dubbo.metadata.store.MetadataReport

@SPI("redis")
public interface MetadataReportFactory {
    @Adaptive({"protocol"})
    MetadataReport getMetadataReport(URL url);
}

Custom Metadata Storage

The following example describes the Redis storage.

Create a new project that needs to support the following modifications:

Extend AbstractMetadataReport

public class RedisMetadataReport extends AbstractMetadataReport {
    private final static Logger logger = LoggerFactory.getLogger(RedisMetadataReport.class);
    final JedisPool pool;
    public RedisMetadataReport(URL url) {
        super(url);
        pool = new JedisPool(new JedisPoolConfig(), url.getHost(), url.getPort());
    }
    @Override
    protected void doStoreProviderMetadata(ProviderMetadataIdentifier providerMetadataIdentifier, String serviceDefinitions) {
        this.storeMetadata(providerMetadataIdentifier, serviceDefinitions);
    }
    @Override
    protected void doStoreConsumerMetadata(ConsumerMetadataIdentifier consumerMetadataIdentifier, String value) {
        this.storeMetadata(consumerMetadataIdentifier, value);
    }
    private void storeMetadata(MetadataIdentifier metadataIdentifier, String v) {
        try (Jedis jedis = pool.getResource()) {
            jedis.set(metadataIdentifier.getIdentifierKey() + META_DATA_SOTRE_TAG, v);
        } catch (Throwable e) {
            logger.error("Failed to put " + metadataIdentifier + " to redis " + v + ", cause: " + e.getMessage(), e);
            throw new RpcException("Failed to put " + metadataIdentifier + " to redis " + v + ", cause: " + e.getMessage(), e);
        }
    }
}

Extend AbstractMetadataReportFactory

public class RedisMetadataReportFactory extends AbstractMetadataReportFactory {
    @Override
    public MetadataReport createMetadataReport(URL url) {
        return new RedisMetadataReport(url);
    }
}

Add MetadataReportFactory

META-INF/dubbo/internal/org.apache.dubbo.metadata.store.MetadataReportFactory

redis=org.apache.dubbo.metadata.store.redis.RedisMetadataReportFactory

Just package the above modifications and the project into a jar file, then configure the metadata center’s URL: redis://10.20.153.10:6379.

Thus, a custom metadata storage can now run.

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Last modified September 30, 2024: Update & Translate Overview Docs (#3040) (d37ebceaea7)