2

Spring Integration 具有 ZooKeeper 支持，如https://docs.spring.io/spring-integration/reference/html/zookeeper.html中所述， 但是该文档非常模糊。

它建议在 bean 下面添加，但没有详细说明当节点被授予领导权时如何启动/停止轮询器。

@Bean
public LeaderInitiatorFactoryBean leaderInitiator(CuratorFramework client) {
    return new LeaderInitiatorFactoryBean()
                .setClient(client)
                .setPath("/siTest/")
                .setRole("cluster");
}

我们是否有任何示例说明如何使用 Zookeeper 在任何时候确保以下轮询器在集群中只运行一次？

@Component
public class EventsPoller {

    public void pullEvents() {
        //pull events should be run by only one node in the cluster at any time
    }
}
4

1 回答 1

2

当它成为领导者并且其领导权被撤销时，它会LeaderInitiator发出一个OnGrantedEventand 。OnRevokedEvent

请参阅https://docs.spring.io/spring-integration/reference/html/messaging-endpoints-chapter.html#endpoint-roles和下一个https://docs.spring.io/spring-integration/reference/html /messaging-endpoints-chapter.html#leadership-event-handling了解有关这些事件处理以及它如何影响特定角色中的组件的更多信息。

虽然我同意 Zookkeper 章节必须有一些链接到该SmartLifecycleRoleController章节。随意就此事提出JIRA，欢迎贡献！

更新

这是我在测试中所做的：

@RunWith(SpringRunner.class)
@DirtiesContext
public class LeaderInitiatorFactoryBeanTests extends ZookeeperTestSupport {

    private static CuratorFramework client;

    @Autowired
    private PollableChannel stringsChannel;

    @BeforeClass
    public static void getClient() throws Exception {
        client = createNewClient();
    }

    @AfterClass
    public static void closeClient() {
        if (client != null) {
            client.close();
        }
    }

    @Test
    public void test() {
        assertNotNull(this.stringsChannel.receive(10_000));
    }


    @Configuration
    @EnableIntegration
    public static class Config {

        @Bean
        public LeaderInitiatorFactoryBean leaderInitiator(CuratorFramework client) {
            return new LeaderInitiatorFactoryBean()
                    .setClient(client)
                    .setPath("/siTest/")
                    .setRole("foo");
        }

        @Bean
        public CuratorFramework client() {
            return LeaderInitiatorFactoryBeanTests.client;
        }

        @Bean
        @InboundChannelAdapter(channel = "stringsChannel", autoStartup = "false", poller = @Poller(fixedDelay = "100"))
        @Role("foo")
        public Supplier<String> inboundChannelAdapter() {
            return () -> "foo";
        }

        @Bean
        public PollableChannel stringsChannel() {
            return new QueueChannel();
        }

    }

}

我在日志中有这样的内容：

2018-12-14 10:12:33,542 DEBUG [Curator-LeaderSelector-0] [org.springframework.integration.support.SmartLifecycleRoleController] - Starting [leaderInitiatorFactoryBeanTests.Config.inboundChannelAdapter.inboundChannelAdapter] in role foo
2018-12-14 10:12:33,578 DEBUG [Curator-LeaderSelector-0] [org.springframework.integration.support.SmartLifecycleRoleController] - Stopping [leaderInitiatorFactoryBeanTests.Config.inboundChannelAdapter.inboundChannelAdapter] in role foo
于 2018-12-13T16:47:05.700 回答