Soul source learning [14] – Deep into divide plug-in

This article focuses on how HTTP back-end services in the Soul Gateway framework register with Divide plug-ins once they are started.

background

As described earlier, the Divide load balancing plug-in can forward HTTP requests to soul-admin-configured back-end services.

HTTP service registration to the gateway source code analysis

Back-end service side source code analysis

• The soul-example-http backend service, for example, introduces the soul-spring-boot-starter-client-springMVC package, which contains only one configuration class. Including a SpringMvcClientBeanPostProcessor type of bean; (implementation of BeanPostProcessor interface for Bean initialization post-processing;)

  <dependency>
      <groupId>org.dromara</groupId>
      <artifactId>soul-spring-boot-starter-client-springmvc</artifactId>
      <version>${soul.version}</version>
  </dependency>
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  @Bean
  public SpringMvcClientBeanPostProcessor springHttpClientBeanPostProcessor(final SoulSpringMvcConfig soulSpringMvcConfig) {
      return new SpringMvcClientBeanPostProcessor(soulSpringMvcConfig);
  }
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• SpringMvcClientBeanPostProcessor initialization, contains url registration;

  

• The backend Http service Controller needs to use the SoulSpringMvcClient annotation for service registration.

  @RestController @RequestMapping("/test") @SoulSpringMvcClient(path = "/test/**") public class HttpTestController { // . }Copy the code

  @RestController
  @RequestMapping("/order")
  @SoulSpringMvcClient(path = "/order")
  public class OrderController {
  // ...
  }
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• Backend triggered when the Http service Controller instantiated SpringMvcClientBeanPostProcessor rear processing, post processing will be registered in the back-end services;

  

• If the registered service path contains an * asterisk, such as /test/** in HttpTestController, it will be placed in the thread pool to perform the asynchronous registration task.

  
  
  

  / / requests into the reference sample url: http://localhost:9095/soul-client/springmvc-register json: {" appName ":" HTTP ", "context" : "HTTP/"," path ":" HTTP/test / * * / ", "pathDesc" : ""," rpcType ":" HTTP ", "the host" : "172.16.21.89." "port":8188, "ruleName":"/http/test/**", "enabled":true, "registerMetaData":false }Copy the code

• After registration, the soul-admin management side will see the backend service.

  

• If the registered service path does not contain an * asterisk, such as OrderController, the principle is similar, except that each method in the class needs to be registered in sequence. Because the method also uses the SoulSpringMvcClient annotation;

  @PostMapping("/save")
  @SoulSpringMvcClient(path = "/save" , desc = "Save order")
  public OrderDTO save(@RequestBody final OrderDTO orderDTO) {
      orderDTO.setName("hello world save order");
      return orderDTO;
  }
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Gateway background side source code analysis

• Soul-admin receives a registration request for the backend service, processing the selector and the rule in turn, focusing only on the registration of the selector.

  

  public String registerSpringMvc(final SpringMvcRegisterDTO dto) { if (dto.isRegisterMetaData()) { MetaDataDO exist = metaDataMapper.findByPath(dto.getPath()); If (objects.isNULL (exist)) {saveSpringMvcMetaData(dTO); if (objects.isnull (exist)) {saveSpringMvcMetaData(dto); } } String selectorId = handlerSpringMvcSelector(dto); handlerSpringMvcRule(selectorId, dto); return SoulResultMessage.SUCCESS; }Copy the code

• If the selector under the current contextPath does not exist, it needs to be registered.

  selectorId = registerSelector(contextPath, dto.getRpcType(), dto.getAppName(), uri);
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• If the selector already exists, the list of back-end services needs to be updated, which involves updating the DB, local caching, and notifying the Soul gateway cluster.

  

  // update db
  selectorMapper.updateSelective(selectorDO);
  // submit upstreamCheck
  upstreamCheckService.submit(contextPath, addDivideUpstream);
  // publish change event.
  eventPublisher.publishEvent(new DataChangedEvent(ConfigGroupEnum.SELECTOR, DataEventTypeEnum.UPDATE,
          Collections.singletonList(selectorData)));
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• After the selector backend service list is updated, the Configuration column is displayed on the soul-admin side. If the back-end service is not started, the column is empty;

  

conclusion

• When the backend Http service instance is started, it relies on BeanPostProcessor to register the service uniformly after Bean initialization.

• Only beans with SoulSpringMvcClient annotations need to register with the gateway, which is to make an HTTP request to the gateway background.

• After receiving the registration request, the gateway background processes the context -> selector -> rule in sequence. It is worth noting that the registration of back-end services also involves the synchronization of configuration data. For details, see the previous analysis.

series

• Soul source learning [1] – preliminary exploration
• Soul source learning [2] – divide load balancing plug-in
• Soul source learning [3] – Dubbo plug-in
• Soul source learning [4] – RateLimiter stream limiting plug-in
• Soul source learning [5] – SpringCloud plug-in
• Soul source learning [6] – Chain of responsibility mode
• Soul source learning [7] – Data synchronization strategy websocket synchronization
• [8] – Data synchronization strategy for ZooKeeper synchronization
• [9] – ZooKeeper Synchronization (2)
• Soul source learning [10] – Observer mode application
• Soul source learning [11] – Data synchronization strategy HTTP long poll synchronization
• Soul source learning [12] – Data Synchronization strategy HTTP long Poll synchronization (2)
• Soul source learning [13] – data synchronization strategy comparison