dubbo超时重试概述
consumer端和provider端都可以设置timeout。
超时优先级：consumer方法级>provider方法级>consumer接口级>provider接口级>consumer级>provider级
当consumer端调用超时，会触发重试调用。
重试对应的配置属性是retries。默认的重试次数是2。就是说，当调用超时，会最多重试2次，如果仍然失败，会提示异常。
对于查询或删除来说，接口重试是幂等的。
对于新增数据，如果retries>0，则要做幂等处理，否则会造成重复数据入库而产生bug。安全起见，可单独设置retries=0。
【说明】在直连的情况下，是不会触发重试的。
代码
服务接口定义：
package dubbodemo.contract;
public interface HelloWord {
String say();
String add(String str);
}
Provider application.yml dubbo配置：
dubbo: application: name: zhanggz-dubbodemo registry: # address: N/A address: zookeeper://127.0.0.1:2181 protocol: port: 28088 name: dubbo scan: base-packages: dubbodemo.provider provider: timeout: 2200 retries: 3
Provider代码：
package dubbodemo.provider; import dubbodemo.contract.HelloWord; import lombok.extern.slf4j.Slf4j; import org.apache.commons.lang3.RandomUtils; import org.apache.dubbo.config.annotation.Service; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @Slf4j @Service(retries = 3) @SpringBootApplication public class ProviderApplication implements HelloWord { public static void main(String[] args) { SpringApplication.run(ProviderApplication.class); } public String add(String str) { log.info("add入参:{}", str); long start = System.currentTimeMillis(); try { //int i=1/0; try { int r = RandomUtils.nextInt(1000, 2000); log.info("sleep time={}", r); Thread.sleep(r); } catch (InterruptedException e) { e.printStackTrace(); } return "test retry:" + str; } finally { log.info("duration={}", System.currentTimeMillis() - start); } } public String say() { return ("hello"); } }
Consumer application.yml dubbo配置：
dubbo: application: name: zhanggz-dubbodemo-consumer registry: address: zookeeper://127.0.0.1:2181 # address: N/A protocol: name: dubbo consumer: timeout: 1000 # retries: 0
Consumer代码：
package dubbodemo.consumer; import dubbodemo.contract.HelloWord; import lombok.extern.slf4j.Slf4j; import org.apache.dubbo.config.annotation.Reference; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.test.context.junit4.SpringRunner; @Slf4j @RunWith(SpringRunner.class) @SpringBootTest public class DubboConsumerTest { @Reference(/*url = "dubbo://localhost:28088",*/) private HelloWord helloWord; @Test public void testAddRetry() { long start = System.currentTimeMillis(); log.info("请求开始..."); try { String str = helloWord.add("str"); log.info("返回值={}", str); } finally { log.info("duration=={}", System.currentTimeMillis() - start); } } }
测试结论
--------直连的情况下，测试dubbo调用超时。
将Provider方法利用Thread.sleep(2000)来模拟超时。
consumer不设置timeout（默认值=1000ms），改变provider的timeout值
【provider】
设置provider.timeout=1000 ,因为方法执行耗时是2000，会有WARN提示。
2020-07-23 18:53:57.427 INFO 13356 --- [:20880-thread-2] dubbodemo.provider.ProviderApplication : duration=2000 2020-07-23 18:53:57.432 WARN 13356 --- [:20880-thread-2] o.apache.dubbo.rpc.filter.TimeoutFilter : [DUBBO] invoke time out. method: add arguments: [str] , url is dubbo://192.168.40.69:20880/dubbodemo.contract.HelloWord?anyhost=true&application=zhanggz-dubbodemo&bean.name=ServiceBean:dubbodemo.contract.HelloWord&bind.ip=192.168.40.69&bind.port=20880&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=dubbodemo.contract.HelloWord&methods=add,say&pid=13356&qos.enable=false®ister=true&release=2.7.3&side=provider&timeout=1000×tamp=1595501612605, invoke elapsed 2005 ms., dubbo version: 2.7.3, current host: 192.168.40.69
【provider】
设置provider.timeout=2200, 方法耗时2000<2200，不会提示invoke timeout。
2020-07-23 18:57:16.949 INFO 12280 --- [:20880-thread-2] dubbodemo.provider.ProviderApplication : duration=2000
不管Provider如何设置timeout，因为Consumer的timeout=1000，所以consumer都会收到timeout异常。
2020-07-23 18:53:56.273 INFO 13216 --- [ main] dubbodemo.consumer.DubboConsumerTest : duration==1040
org.apache.dubbo.rpc.RpcException: Invoke remote method timeout. method: add, provider: dubbo://localhost:20880/dubbodemo.contract.HelloWord?application=zhanggz-dubbodemo-consumer&interface=dubbodemo.contract.HelloWord&lazy=false&pid=13216&qos.enable=false®ister.ip=192.168.40.69&remote.application=&side=consumer&sticky=false, cause: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2020-07-23 18:53:55.250, end time: 2020-07-23 18:53:56.272, client elapsed: 106 ms, server elapsed: 916 ms, timeout: 1000 ms, request: Request [id=0, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=add, parameterTypes=[class java.lang.String], arguments=[str], attachments={path=dubbodemo.contract.HelloWord, interface=dubbodemo.contract.HelloWord, version=0.0.0}]], channel: /192.168.40.69:1813 -> /192.168.40.69:20880
----------------------------- Provider服务停止后，客户端无法启动
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dubbodemo.consumer.DubboConsumerTest': Injection of @Reference dependencies is failed; nested exception is org.apache.dubbo.rpc.RpcException: Fail to create remoting client for service(dubbo://localhost:20880/dubbodemo.contract.HelloWord?application=zhanggz-dubbodemo-consumer&codec=dubbo&heartbeat=60000&interface=dubbodemo.contract.HelloWord&lazy=false&pid=5236&qos.enable=false®ister.ip=192.168.40.69&remote.application=&side=consumer&sticky=false&timeout=2200): client(url: dubbo://localhost:20880/dubbodemo.contract.HelloWord?application=zhanggz-dubbodemo-consumer&codec=dubbo&heartbeat=60000&interface=dubbodemo.contract.HelloWord&lazy=false&pid=5236&qos.enable=false®ister.ip=192.168.40.69&remote.application=&side=consumer&sticky=false&timeout=2200) failed to connect to server localhost/127.0.0.1:20880, error message is:Connection refused: no further information: /192.168.40.69:20880
consumer端设置dubbo.consumer.check=false。则可以启动consumer服务。
check属性说明：Check if service provider exists, if not exists, it will be fast fail
不过，当调用远程服务的时候，由于远程服务处于停止状态，所以当然会报错。
连接注册中心时的错误提示：
org.apache.dubbo.rpc.RpcException: No provider available from registry 192.168.40.84:2181 for service dubbodemo.contract.HelloWord on consumer 192.168.40.69 use dubbo version 2.7.3, please check status of providers(disabled, not registered or in blacklist).
直连的错误提示：
org.apache.dubbo.rpc.RpcException: Failed to invoke remote method: add, provider: dubbo://localhost:20880/dubbodemo.contract.HelloWord?application=zhanggz-dubbodemo-consumer&check=false&interface=dubbodemo.contract.HelloWord&lazy=false&pid=12504&qos.enable=false®ister.ip=192.168.40.69&remote.application=&side=consumer&sticky=false&timeout=2200, cause: message can not send, because channel is closed . url:dubbo://localhost:20880/dubbodemo.contract.HelloWord?application=zhanggz-dubbodemo-consumer&check=false&codec=dubbo&heartbeat=60000&interface=dubbodemo.contract.HelloWord&lazy=false&pid=12504&qos.enable=false®ister.ip=192.168.40.69&remote.application=&side=consumer&sticky=false&timeout=2200
----------------------------------
consumer端，设置retries=3
2020-07-24 17:12:57.389 INFO 7468 --- [ main] dubbodemo.consumer.DubboConsumerTest : 请求开始... 2020-07-24 17:13:00.202 INFO 7468 --- [ main] dubbodemo.consumer.DubboConsumerTest : 返回值=test retry:str 2020-07-24 17:13:00.202 INFO 7468 --- [ main] dubbodemo.consumer.DubboConsumerTest : duration==2813
provider端：最多会被执行1+retries=4次
2020-07-24 17:12:57.540 INFO 2372 --- [28088-thread-17] dubbodemo.provider.ProviderApplication : add入参:str 2020-07-24 17:12:57.541 INFO 2372 --- [28088-thread-17] dubbodemo.provider.ProviderApplication : r=1169 2020-07-24 17:12:58.444 INFO 2372 --- [28088-thread-18] dubbodemo.provider.ProviderApplication : add入参:str 2020-07-24 17:12:58.444 INFO 2372 --- [28088-thread-18] dubbodemo.provider.ProviderApplication : r=1934 2020-07-24 17:12:58.711 INFO 2372 --- [28088-thread-17] dubbodemo.provider.ProviderApplication : duration=1170 2020-07-24 17:12:59.461 INFO 2372 --- [28088-thread-19] dubbodemo.provider.ProviderApplication : add入参:str 2020-07-24 17:12:59.461 INFO 2372 --- [28088-thread-19] dubbodemo.provider.ProviderApplication : r=736 2020-07-24 17:13:00.198 INFO 2372 --- [28088-thread-19] dubbodemo.provider.ProviderApplication : duration=737 2020-07-24 17:13:00.379 INFO 2372 --- [28088-thread-18] dubbodemo.provider.ProviderApplication : duration=1935
优先级测试
Provider设置retries=1 consumer设置retries=3，服务端会重试1次。
注意，log里的Tried 2 times 指的是一共调用了2次。即首次+重试的那1次。
org.apache.dubbo.rpc.RpcException: Failed to invoke the method add in the service dubbodemo.contract.HelloWord. Tried 2 times of the providers [192.168.40.84:28088, 192.168.40.69:28088] (2/2) from the registry 192.168.40.84:2181 on the consumer 192.168.40.69 using the dubbo version 2.7.3. Last error is: Invoke remote method timeout. method: add, provider: dubbo://192.168.40.84:28088/dubbodemo.contract.HelloWord?anyhost=true&application=zhanggz-dubbodemo-consumer&bean.name=ServiceBean:dubbodemo.contract.HelloWord&check=false&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=dubbodemo.contract.HelloWord&lazy=false&methods=add,say&pid=23324&qos.enable=false®ister=true®ister.ip=192.168.40.69&release=2.7.3&remote.application=zhanggz-dubbodemo&retries=1&revision=1.0-SNAPSHOT&side=consumer&sticky=false&timeout=1000×tamp=1596179853357, cause: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2020-07-31 15:33:52.809, end time: 2020-07-31 15:33:53.826, client elapsed: 1 ms, server elapsed: 1016 ms, timeout: 1000 ms, request: Request [id=1, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=add, parameterTypes=[class java.lang.String], arguments=[str], attachments={path=dubbodemo.contract.HelloWord, interface=dubbodemo.contract.HelloWord, version=0.0.0, timeout=1000}]], channel: /192.168.40.69:3666 -> /192.168.40.84:28088
Provider设置retries=0 consumer设置retries=3，服务端不会重试。
org.apache.dubbo.rpc.RpcException: Failed to invoke the method add in the service dubbodemo.contract.HelloWord. Tried 1 times of the providers [192.168.40.69:28088] (1/1) from the registry 127.0.0.1:2181 on the consumer 192.168.40.69 using the dubbo version 2.7.3. Last error is: Invoke remote method timeout. method: add, provider: dubbo://192.168.40.69:28088/dubbodemo.contract.HelloWord?anyhost=true&application=zhanggz-dubbodemo-consumer&bean.name=ServiceBean:dubbodemo.contract.HelloWord&check=false&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=dubbodemo.contract.HelloWord&lazy=false&methods=add,say&pid=9436&qos.enable=false®ister=true®ister.ip=192.168.40.69&release=2.7.3&remote.application=zhanggz-dubbodemo&retries=0&side=consumer&sticky=false&timeout=1000×tamp=1596170589487, cause: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2020-07-31 12:43:36.395, end time: 2020-07-31 12:43:37.419, client elapsed: 111 ms, server elapsed: 912 ms, timeout: 1000 ms, request: Request [id=0, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=add, parameterTypes=[class java.lang.String], arguments=[str], attachments={path=dubbodemo.contract.HelloWord, interface=dubbodemo.contract.HelloWord, version=0.0.0, timeout=1000}]], channel: /192.168.40.69:2295 -> /192.168.40.69:28088