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Posted to commits@servicecomb.apache.org by GitBox <gi...@apache.org> on 2020/11/28 02:34:30 UTC

[GitHub] [servicecomb-java-chassis] xhanthow opened a new issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

xhanthow opened a new issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091


   


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[GitHub] [servicecomb-java-chassis] wujimin commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
wujimin commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735520077


   是的，新的Filter机制是将旧的各种扩展点全部归一化了，要实现的功能还是一样的  
   Filter的成员确实允许Autowire了  
   要切回eventloop，可以：  
   ```java
     VertxTransportContext transportContext = invocation.getTransportContext();
     Executor executor = VertxContextExecutor.create(transportContext.getVertxContext());
     future.xxxAsync(xxx, executor)
       .xxxxxx
   ```
   xxx就在eventloop中执行了  
   
   要注意，future有个“特点”，下面用例中第二个apply不一定会在executor中执行，结果是由本线程与executor的真实执行顺序决定的，而这个顺序本身就是不确定的：
   ```java
       @Test
       @Disabled("用于证明jdk的CompletableFuture确实有问题，有较高概率出现，但是也不是必现；为防止CI概率性失败，改为手工执行")
       void completable_future_thread_is_not_stable() {
           for (int idx = 0; idx < LOOP_COUNT; idx++) {
               CompletableFuture.completedFuture(null)
                   .thenApplyAsync(this::apply, executor)
                   .thenApply(this::apply)
                   .join();
           }
   
           assertThat(threadNames).containsExactlyInAnyOrder("main", UT_THREAD_NAME);
       }
   
   ```


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[GitHub] [servicecomb-java-chassis] xhanthow commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735060803


   也就是说这样就不会影响eventloop线程了吧。
   新的Filter机制有设计文档么（是否和Handler设计类似了？），想对着https://issues.apache.org/jira/browse/SCB-1929学习学习。


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[GitHub] [servicecomb-java-chassis] liubao68 commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
liubao68 commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735045387


   看你的描述像是代码本身执行逻辑导致的问题， 即 completableFuture.complete在哪个线程被调用了。 
   
   "Filter中不行" 没看到描述， 不是很清楚这个表达代表的意思。 


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[GitHub] [servicecomb-java-chassis] xhanthow closed issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow closed issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091


   


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[GitHub] [servicecomb-java-chassis] xhanthow commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735525199


   这个类`VertxContextExecutor`在1.2.0中是没有的吧，我看最新代码中是有的。
   学习了~
   刚又debug了下，由于我的`Handler`是第一个，所以剩下的几个（除了最后一个`Handler`：`TransportClientHandler`）都是在我自己定义线程池中执行的。直到最后一个`Handler`执行这个动作就会发生线程切换吧：
   ![线程切换](https://user-images.githubusercontent.com/7291995/100566048-f695e500-32ff-11eb-8d9f-77dc17b00151.png)
   这个动作和`VertxContextExecutor`这个类逻辑差不多


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[GitHub] [servicecomb-java-chassis] xhanthow edited a comment on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow edited a comment on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735513368


   嗯，把代码下下来看了下，这里就启动了`Filter`链（感觉和之前的`Handler`有点像，`invocation.next(xxx)`）
   ```java
     public CompletableFuture<Response> onFilter(Invocation invocation) {
       if (!filter.enabled()) {
         return nextNode.onFilter(invocation);
       }
       
       return AsyncUtils.tryCatch(() -> filter.onFilter(invocation, nextNode))
           .thenApply(this::rethrowExceptionInResponse);
     }
   ```
   
   而且现在`Filter`可以使用`Autowire`了吧 :)
   ```java
   engine.getApplicationContext().getAutowireCapableBeanFactory().autowireBean(filter)
   ```
   
   不过我现在还有个疑问，就是我在`Handler`中用了异步（如issue中第一个描述中的代码），自己定义的线程池，然后我`debug`的时候发现后续的`Invocation#next`执行的时候也都在我自定义的线程池中执行，后续的操作还有可能切换到eventloop线程中执行么？
   
   


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[GitHub] [servicecomb-java-chassis] wujimin commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
wujimin commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735051226


   基本上我认为这是一个设计缺陷  
   当初定义HttpServerFilter时，仅仅为了用于干预一下codec逻辑而已  
   相关的缺陷，在这里也有一定的描述：https://issues.apache.org/jira/browse/SCB-1929  
     
   使用新的Filter机制，可以解决reactive认证/鉴权的问题  
   不过Filter机制还没有正式发布，我在自己的项目里正在试用  
     
   线程变换的问题，从能不能跑的角度看，应该是没问题，但是能不能跑得好，这个需要你来评估  
   比如，所有请求都要走认证/鉴权，所有的请求就都跑到你这个线程池里去了，是否顶得住？  
   
   另外：CompletableFuture使用指定线程池执行，可以使用它的带async后缀的方法，并指定你想要的executor即可，代码会清晰不少


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[GitHub] [servicecomb-java-chassis] xhanthow commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735049419


   completableFuture.complete在是在我自己定义的线程池中执行的，我就问这个会影响效率么？因为开始都是在eventloop中执行的，然后切换到了自己的线程中。
   "Filter"中不行和这个issue描述差不多：https://github.com/apache/servicecomb-java-chassis/issues/1324
   


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[GitHub] [servicecomb-java-chassis] xhanthow commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735566821


   好的，了解了。谢谢~


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[GitHub] [servicecomb-java-chassis] xhanthow edited a comment on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow edited a comment on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735513368


   嗯，把代码下下来看了下，这里就启动了`Filter`链（感觉和之前的`Handler`有点像，`invocation.next(xxx)`）
   ```java
     public CompletableFuture<Response> onFilter(Invocation invocation) {
       if (!filter.enabled()) {
         return nextNode.onFilter(invocation);
       }
       
       return AsyncUtils.tryCatch(() -> filter.onFilter(invocation, nextNode))
           .thenApply(this::rethrowExceptionInResponse);
     }
   ```
   
   而且现在`Filter`可以使用`Autowire`了吧 :)
   ```java
   engine.getApplicationContext().getAutowireCapableBeanFactory().autowireBean(filter)
   ```
   
   不过我现在还有个疑问，就是我在`Handler`中用了异步（如issue中第一个描述中的代码），自己定义的线程池，然后我`debug`的时候发现后续的`Invocation#next`执行的时候也都在我自定义的线程池中执行，后续的操作还有可能切换到eventloop线程中执行么？
   
   ![Snipaste_2020-10-22_19-47-12](https://user-images.githubusercontent.com/7291995/100563289-052cce00-32f9-11eb-910f-fa6be92cef29.png)
   
   
   


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[GitHub] [servicecomb-java-chassis] wujimin commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
wujimin commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735159814


   是的，不会影响eventloop  
   还没有文档，只有那个issue，相应的代码，可以看那issue的subTask对应的PR，点进去都有链接


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[GitHub] [servicecomb-java-chassis] xhanthow edited a comment on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow edited a comment on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735049419


   completableFuture.complete在是在我自己定义的线程池中执行的，我就想问下这个会影响效率么？因为开始都是在eventloop中执行的，然后切换到了自己的线程中。
   "Filter"中不行和这个issue描述差不多：https://github.com/apache/servicecomb-java-chassis/issues/1324
   


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[GitHub] [servicecomb-java-chassis] xhanthow commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735513368


   嗯，把代码下下来看了下，这里就启动了`Filter`链（感觉和之前的`Handler`有点像，`invocation.next(xxx)`）
   ```java
     public CompletableFuture<Response> onFilter(Invocation invocation) {
       if (!filter.enabled()) {
         return nextNode.onFilter(invocation);
       }
       
       return AsyncUtils.tryCatch(() -> filter.onFilter(invocation, nextNode))
           .thenApply(this::rethrowExceptionInResponse);
     }
   ```
   
   而且现在`Filter`可以使用`Autowire`了吧 :)
   ```java
   engine.getApplicationContext().getAutowireCapableBeanFactory().autowireBean(filter)
   ```
   
   不过我现在还有个疑问，就是我在`Handler`中用了异步（如issue中第一个描述中的代码），自己定义的线程池，然后我`debug`的时候发现后续的`Invocation#next`执行的时候也都在我自定义的线程池中执行，后续的操作还有可能切换到eventloop线程中执行么？
   
   


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[GitHub] [servicecomb-java-chassis] wujimin commented on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
wujimin commented on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735526561


   1.x系列早就是维护状态了，新特性都在2.x中，Filter估计在3.x中发布  
   `VertxContextExecutor`实际就是对runOnContext的包装，为了方便与CompletableFuture配合使用


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[GitHub] [servicecomb-java-chassis] xhanthow edited a comment on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow edited a comment on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735513368


   嗯，把代码下下来看了下，这里就启动了`Filter`链（感觉和之前的`Handler`有点像，`invocation.next(xxx)`）
   ```java
     public CompletableFuture<Response> onFilter(Invocation invocation) {
       if (!filter.enabled()) {
         return nextNode.onFilter(invocation);
       }
       
       return AsyncUtils.tryCatch(() -> filter.onFilter(invocation, nextNode))
           .thenApply(this::rethrowExceptionInResponse);
     }
   ```
   
   而且现在`Filter`可以使用`Autowire`了吧 :)
   ```java
   engine.getApplicationContext().getAutowireCapableBeanFactory().autowireBean(filter)
   ```
   
   不过我现在还有个疑问，就是我在`Handler`中用了异步（如issue中第一个描述中的代码），自己定义的线程池，然后我`debug`的时候发现后续的`Invocation#next`执行的时候也都在我自定义的线程池中执行，后续的操作还有可能切换到eventloop线程中执行么？
   
   
   


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[GitHub] [servicecomb-java-chassis] xhanthow edited a comment on issue #2091: 为什么Handler中可以使用异步而Filter中不行了？

Posted by GitBox <gi...@apache.org>.
xhanthow edited a comment on issue #2091:
URL: https://github.com/apache/servicecomb-java-chassis/issues/2091#issuecomment-735513368


   嗯，把代码下下来看了下，这里就启动了`Filter`链（感觉和之前的`Handler`有点像，`invocation.next(xxx)`）
   ```java
     public CompletableFuture<Response> onFilter(Invocation invocation) {
       if (!filter.enabled()) {
         return nextNode.onFilter(invocation);
       }
       
       return AsyncUtils.tryCatch(() -> filter.onFilter(invocation, nextNode))
           .thenApply(this::rethrowExceptionInResponse);
     }
   ```
   
   而且现在`Filter`可以使用`Autowire`了吧 :)
   ```java
   engine.getApplicationContext().getAutowireCapableBeanFactory().autowireBean(filter)
   ```
   
   不过我现在还有个疑问，就是我在`Handler`中用了异步（如issue中第一个描述中的代码），自己定义的线程池，然后我`debug`的时候发现后续的`Invocation#next`执行的时候也都在我自定义的线程池中执行，后续的操作还有可能切换到eventloop线程中执行么？
   
   ![thread](https://user-images.githubusercontent.com/7291995/100563414-4d4bf080-32f9-11eb-815d-4ee81b8f661b.png)
   


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