Registry Center Extension

Registry Center Extension

Extension Description

Responsible for the registration and discovery of services.

Extension Interfaces

  • org.apache.dubbo.registry.RegistryFactory
  • org.apache.dubbo.registry.Registry

Extension Configuration

  1. <!-- Define the registry -->
  2. <dubbo:registry id="xxx1" address="xxx://ip:port" />
  3. <!-- Reference the registry, if the registry attribute is not configured, it will automatically scan the registry configuration in the ApplicationContext -->
  4. <dubbo:service registry="xxx1" />
  5. <!-- Reference the default value of the registry, when <dubbo:service> does not configure the registry attribute, use this configuration -->
  6. <dubbo:provider registry="xxx1" />

Extension Contracts

RegistryFactory.java：

  1. public interface RegistryFactory {
  2.     /**
  3.      * Connect to the registry.
  4.      * 
  5.      * The connection to the registry must handle the following contracts:<br>
  6.      * 1. Setting check=false indicates no connection check, otherwise an exception will be thrown if it cannot connect.<br>
  7.      * 2. Supports username:password authentication based on the URL.<br>
  8.      * 3. Supports backup=10.20.153.10 alternative registry cluster addresses.<br>
  9.      * 4. Supports file=registry.cache local disk file caching.<br>
  10.      * 5. Supports timeout=1000 request timeout settings.<br>
  11.      * 6. Supports session=60000 session timeout or expiration settings.<br>
  12.      * 
  13.      * @param url The registry address, must not be null
  14.      * @return The registry reference, never returns null
  15.      */
  16.     Registry getRegistry(URL url); 
  17. }

RegistryService.java：

  1. public interface RegistryService { // Registry extends RegistryService 
  2.     /**
  3.      * Register a service.
  4.      * 
  5.      * Registration must handle the following contracts:<br>
  6.      * 1. If the URL sets check=false, no error will be reported on registration failure, and it will retry in the background; otherwise, an exception will be thrown.<br>
  7.      * 2. If the URL sets dynamic=false, it needs to be persisted; otherwise, it should be automatically deleted when the registrant exits abnormally due to power failure or other circumstances.<br>
  8.      * 3. If the URL sets category=overrides, it indicates classified storage, with the default category being providers, allowing notifications of partial data by category.<br>
  9.      * 4. Data must not be lost when the registry restarts or during network fluctuations, including automatic deletion of data upon disconnection.<br>
  10.      * 5. URLs with the same URI but different parameters are allowed to coexist and cannot be overwritten.<br>
  11.      * 
  12.      * @param url The registration information, must not be null, such as: dubbo://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
  13.      */
  14.     void register(URL url);
  16.     /**
  17.      * Unregister a service.
  18.      * 
  19.      * Unregistration must handle the following contracts:<br>
  20.      * 1. If it is dynamic=false persistent storage data and the registration data cannot be found, throw IllegalStateException, otherwise ignore.<br>
  21.      * 2. Unregister based on full URL match.<br>
  22.      * 
  23.      * @param url The registration information, must not be null, such as: dubbo://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
  24.      */
  25.     void unregister(URL url);
  27.     /**
  28.      * Subscribe to a service.
  29.      * 
  30.      * Subscription must handle the following contracts:<br>
  31.      * 1. If the URL sets check=false, no error will be reported on subscription failure, and it will retry in the background.<br>
  32.      * 2. If the URL sets category=overrides, only notify the specified categorized data; multiple categories are separated by commas and wildcard '*' is allowed to subscribe to all categorized data.<br>
  33.      * 3. Allows querying based on interface, group, version, classifier, such as: interface=com.alibaba.foo.BarService&version=1.0.0<br>
  34.      * 4. The query criteria allow wildcards, subscribing to all groups of all versions of all interfaces, or: interface=*&group=*&version=*&classifier=*<br>
  35.      * 5. When the registry restarts or during network fluctuations, subscription requests must be automatically restored.<br>
  36.      * 6. URLs with the same URI but different parameters are allowed to coexist and cannot be overwritten.<br>
  37.      * 7. The subscription process must be blocked, returning only after the first notification is completed.<br>
  38.      * 
  39.      * @param url The subscription criteria, must not be null, such as: consumer://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
  40.      * @param listener The change event listener, must not be null
  41.      */
  42.     void subscribe(URL url, NotifyListener listener);
  44.     /**
  45.      * Unsubscribe from a service.
  46.      * 
  47.      * Unsubscription must handle the following contracts:<br>
  48.      * 1. If there is no subscription, just ignore it.<br>
  49.      * 2. Unsubscribe based on full URL match.<br>
  50.      * 
  51.      * @param url The subscription criteria, must not be null, such as: consumer://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
  52.      * @param listener The change event listener, must not be null
  53.      */
  54.     void unsubscribe(URL url, NotifyListener listener);
  56.     /**
  57.      * Query the registration list, corresponding to the push mode of subscription, here it is the pull mode, returning results only once.
  58.      * 
  59.      * @see org.apache.dubbo.registry.NotifyListener#notify(List)
  60.      * @param url The query criteria, must not be null, such as: consumer://10.20.153.10/com.alibaba.foo.BarService?version=1.0.0&application=kylin
  61.      * @return The list of registered information, may be empty, meaning the same as the parameters of {@link org.apache.dubbo.registry.NotifyListener#notify(List<URL>)}.
  62.      */
  63.     List<URL> lookup(URL url);
  65. }

NotifyListener.java：

  1. public interface NotifyListener { 
  2.     /**
  3.      * Triggered when a service change notification is received.
  4.      * 
  5.      * The notification must handle the following contracts:<br>
  6.      * 1. Always notify the full set of data dimensioned by service interface and data type, i.e., it will not notify partial data of the same type from a service, and the user does not need to compare the previous notification results.<br>
  7.      * 2. The first notification during subscription must be a full notification of all types of data for a service.<br>
  8.      * 3. During changes, different types of data may be notified separately, for example: providers, consumers, routes, overrides; only one type may be notified, but that type’s data must be complete, not incremental.<br>
  9.      * 4. If any type of data is empty, an empty protocol notification with a category parameter must be sent.<br>
  10.      * 5. The notifier (i.e., the registry implementation) must ensure the order of notifications; for instance: single-threaded pushes, queue serialization, version comparison.<br>
  11.      * 
  12.      * @param urls The list of registered information, never null, meaning the same as the return value of {@link org.apache.dubbo.registry.RegistryService#lookup(URL)}.
  13.      */
  14.     void notify(List<URL> urls);
  16. }

Known Extensions

org.apache.dubbo.registry.support.dubbo.DubboRegistryFactory

Extension Example

Maven Project Structure:

  1. src
  2.  |-main
  3.     |-java
  4.         |-com
  5.             |-xxx
  6.                 |-XxxRegistryFactory.java (implementing RegistryFactory interface)
  7.                 |-XxxRegistry.java (implementing Registry interface)
  8.     |-resources
  9.         |-META-INF
  10.             |-dubbo
  11.                 |-org.apache.dubbo.registry.RegistryFactory (plain text file, content: xxx=com.xxx.XxxRegistryFactory)

XxxRegistryFactory.java：

  1. package com.xxx;
  3. import org.apache.dubbo.registry.RegistryFactory;
  4. import org.apache.dubbo.registry.Registry;
  5. import org.apache.dubbo.common.URL;
  7. public class XxxRegistryFactory implements RegistryFactory {
  8.     public Registry getRegistry(URL url) {
  9.         return new XxxRegistry(url);
  10.     }
  11. }

XxxRegistry.java：

  1. package com.xxx;
  3. import org.apache.dubbo.registry.Registry;
  4. import org.apache.dubbo.registry.NotifyListener;
  5. import org.apache.dubbo.common.URL;
  7. public class XxxRegistry implements Registry {
  8.     public void register(URL url) {
  9.         // ...
  10.     }
  11.     public void unregister(URL url) {
  12.         // ...
  13.     }
  14.     public void subscribe(URL url, NotifyListener listener) {
  15.         // ...
  16.     }
  17.     public void unsubscribe(URL url, NotifyListener listener) {
  18.         // ...
  19.     }
  20. }

META-INF/dubbo/org.apache.dubbo.registry.RegistryFactory：

  1. xxx=com.xxx.XxxRegistryFactory

Feedback

Was this page helpful?

Yes No

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