About the application of spring management repeated monitoring processing dubbo shutdown

[xiaoheng1]

What is the purpose of the change

About the application of spring management repeated monitoring processing dubbo shutdown.

see more detail from #7093

Brief changelog

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Verifying this change

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[codecov-io]

Codecov Report

Merging #7420 (fc20d59) into master (b5c81d8) will increase coverage by 0.35%.
The diff coverage is 77.77%.

@@             Coverage Diff              @@
##             master    #7420      +/-   ##
============================================
+ Coverage     58.71%   59.06%   +0.35%     
- Complexity      422      456      +34     
============================================
  Files          1043     1043              
  Lines         42514    42524      +10     
  Branches       6208     6226      +18     
============================================
+ Hits          24962    25117     +155     
+ Misses        14769    14619     -150     
- Partials       2783     2788       +5     

Impacted Files	Coverage Δ	Complexity Δ
...ing/context/DubboBootstrapApplicationListener.java	90.90% <77.77%> (-9.10%)	0.00 <0.00> (ø)
...che/dubbo/remoting/transport/mina/MinaChannel.java	35.52% <0.00%> (-14.48%)	14.00% <0.00%> (-2.00%)
.../apache/dubbo/rpc/protocol/AsyncToSyncInvoker.java	62.06% <0.00%> (-10.35%)	0.00% <0.00%> (ø%)
...ache/dubbo/remoting/transport/mina/MinaServer.java	53.33% <0.00%> (-10.00%)	5.00% <0.00%> (-1.00%)
...dubbo/remoting/exchange/support/DefaultFuture.java	80.34% <0.00%> (-6.84%)	0.00% <0.00%> (ø%)
.../threadpool/manager/DefaultExecutorRepository.java	79.03% <0.00%> (-4.84%)	0.00% <0.00%> (ø%)
...ng/transport/dispatcher/WrappedChannelHandler.java	58.69% <0.00%> (-4.35%)	0.00% <0.00%> (ø%)
.../dubbo/remoting/transport/netty4/NettyChannel.java	62.37% <0.00%> (-3.97%)	0.00% <0.00%> (ø%)
...a/org/apache/dubbo/monitor/dubbo/DubboMonitor.java	86.66% <0.00%> (-1.91%)	16.00% <0.00%> (ø%)
...src/main/java/org/apache/dubbo/common/Version.java	70.87% <0.00%> (-1.86%)	0.00% <0.00%> (ø%)
... and 44 more

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[kylixs]

There seems to be a problem with the stop logic. The Shutdown hook is called by the JVM before the JVM exits. It is not good to wait for the dubbo shutdown hook to complete in the Spring close event. Actually Spring also registered shutdown hook, please check org.springframework.context.support.AbstractApplicationContext#registerShutdownHook().

• In the Spring scenario, perhaps we should listen to Spring events to shut down dubbo instead of using shutdown hook. In this case, the life cycle of dubbo is consistent with spring.
• In the Dubbo API scenario, the shutdown hook needs to be registered.

[xiaoheng1]

Now it is precisely because of the existence of Spring hook and Dubbo Hook. As a result, Spring did not block when closing dubbo, and then continued to execute the destruction of Spring Bean. At this time, Dubbo has not completed the destruction, which will cause the database connection not to be obtained. It may be a way to cancel Dubbo Hook directly after hosting to the Spring container.

[xiaoheng1]

like #7317.

If the idea of #7317 is used, should the callback be removed from ShutdownHook? ShutDownHook only calls DubboBootstrap.stop to complete the resource wave work.

[kylixs]

For clarity of responsibilities, the processing logic of dubbo destroy should extracted from the Dubbo shutdown hook, and called it separately in the Spring scenario without relying on the Dubbo shutdown hook.

[xiaoheng1]

So when shutting down the Dubbo service in Spring, do you tend to cancel the registration of DubboShutDownHook?