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Distributed ID Generate Service

License: Apache License 2.0

Java 95.86% Shell 0.58% FreeMarker 2.98% TSQL 0.59%

leaf distributed-id-generator

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leaf's Issues

leaf-core引用不成功

  compile 'com.sankuai.inf.leaf:leaf-parent:1.0.1'
    compile 'com.sankuai.inf.leaf:leaf-server:1.0.1'
    compile 'com.sankuai.inf.leaf:leaf-core:1.0.1'

想尝试用核心包来做开发，发现这样引用引不成功，在maven center也没有找到leaf的包。

关于snowflake的启动流程中leaf_temporary临时节点相关疑问

官方博客介绍snowflake模式下整个启动流程如下：

服务启动时首先检查自己是否写过ZooKeeper leaf_forever节点：

若写过，则用自身系统时间与leaf_forever/${self}节点记录时间做比较，若小于leaf_forever/${self}时间则认为机器时间发生了大步长回拨，服务启动失败并报警。

若未写过，证明是新服务节点，直接创建持久节点leaf_forever/${self}并写入自身系统时间，接下来综合对比其余Leaf节点的系统时间来判断自身系统时间是否准确，具体做法是取leaf_temporary下的所有临时节点(所有运行中的Leaf-snowflake节点)的服务IP：Port，然后通过RPC请求得到所有节点的系统时间，计算sum(time)/nodeSize。

若abs( 系统时间-sum(time)/nodeSize ) < 阈值，认为当前系统时间准确，正常启动服务，同时写临时节点leaf_temporary/${self} 维持租约。

否则认为本机系统时间发生大步长偏移，启动失败并报警。

每隔一段时间(3s)上报自身系统时间写入leaf_forever/${self}。

请问有关第2步、第3步临时节点leaf_temporary的相关逻辑，源码中好像没有，是否是版本更新摒弃了这一部分逻辑。

SegmentIDGenImpl中waitAndSleep方法可能存在code hoisting问题

private void waitAndSleep(SegmentBuffer buffer) {
    int roll = 0;
    while (buffer.getThreadRunning().get()) { //此处会引发code hoisting造成死循环，建议使用必要的同步实现
        roll += 1;
        if(roll > 10000) {
            try {
                Thread.currentThread().sleep(10);
                break;
            } catch (InterruptedException e) {
                logger.warn("Thread {} Interrupted",Thread.currentThread().getName());
                break;
            }
        }
    }
}

`
测试样例

public static void main(String[] args) throws InterruptedException, NoSuchMethodException {
    SegmentIDGenImpl segmentIDGen = new SegmentIDGenImpl();
    final SegmentBuffer buffer = new SegmentBuffer();
    Method waitAndSleepMethod = segmentIDGen.getClass().getDeclaredMethod("waitAndSleep", SegmentBuffer.class);
    new Thread(() -> {
        try {
            waitAndSleepMethod.setAccessible(true);
            waitAndSleepMethod.invoke(segmentIDGen, buffer);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }).start();
    System.out.println(System.nanoTime() + " main thread start sleep");
    Thread.sleep(1000);
    System.out.println(System.nanoTime() + " main thread wake up");
    buffer.getThreadRunning().compareAndSet(false, true); //set value of threadRunning to true
    System.out.println(System.nanoTime() + " main thread - " +
            "the current value of threadRunning : " + buffer.getThreadRunning().get());
}

关于注册到zk的key

我司用的是docker发布，每次发布后容器的ip都不一样，如果拿ip注册到zookeeper,是不是会有问题，本地文件缓存的workerId的意义就不是很大了，你们有遇到这种情况吗？据我了解，美团也是容器发布的，你们的ip是不变的是吗

号段模式双buffer模式中当前号段已下发10%时更新下一个号段，为什么是10%

Snowflake sequence问题

SnowflakeIDGenImpl
//如果是新的ms开始
sequence = RANDOM.nextInt(100);
random没什么意义，而且这样导致同一时刻tps下降。原本同一时刻tps可能为1024,但是random后可能减少100了。

启动leaf-server报错

org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'leafController': Unsatisfied dependency expressed through field 'segmentService'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'SegmentService' defined in file [D:\Leaf\leaf-server\target\classes\com\sankuai\inf\leaf\server\SegmentService.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.sankuai.inf.leaf.server.SegmentService]: Constructor threw exception; nested exception is java.lang.NullPointerException
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:588) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:366) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1272) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:124) ~[spring-boot-1.5.18.RELEASE.jar:1.5.18.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) ~[spring-boot-1.5.18.RELEASE.jar:1.5.18.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) ~[spring-boot-1.5.18.RELEASE.jar:1.5.18.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) ~[spring-boot-1.5.18.RELEASE.jar:1.5.18.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) ~[spring-boot-1.5.18.RELEASE.jar:1.5.18.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) ~[spring-boot-1.5.18.RELEASE.jar:1.5.18.RELEASE]
	at com.sankuai.inf.leaf.server.LeafServerApplication.main(LeafServerApplication.java:10) ~[classes/:na]
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'SegmentService' defined in file [D:\Leaf\leaf-server\target\classes\com\sankuai\inf\leaf\server\SegmentService.class]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.sankuai.inf.leaf.server.SegmentService]: Constructor threw exception; nested exception is java.lang.NullPointerException
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1163) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1107) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:312) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:308) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:208) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1138) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1066) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:585) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	... 19 common frames omitted
Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.sankuai.inf.leaf.server.SegmentService]: Constructor threw exception; nested exception is java.lang.NullPointerException
	at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:154) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:89) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:1155) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	... 30 common frames omitted
Caused by: java.lang.NullPointerException: null
	at com.alibaba.druid.util.JdbcUtils.getDriverClassName(JdbcUtils.java:360) ~[druid-1.0.18.jar:1.0.18]
	at com.alibaba.druid.pool.DruidDataSource.init(DruidDataSource.java:642) ~[druid-1.0.18.jar:1.0.18]
	at com.sankuai.inf.leaf.server.SegmentService.<init>(SegmentService.java:35) ~[classes/:na]
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:na]
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:na]
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:na]
	at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490) ~[na:na]
	at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:142) ~[spring-beans-4.3.18.RELEASE.jar:4.3.18.RELEASE]
	... 32 common frames omitted

关于workId

看下了下源码。workId直接取的zk序列号, 如果ZK序列号超过1023，那岂不是信节点无法加入。是不是需要取摩处理呢，望解答。

号段模式是不是有部分id没有被应用到

Leaf/leaf-core/src/main/java/com/sankuai/inf/leaf/segment/SegmentIDGenImpl.java

Line 237 in 61f53f8

buffer.switchPos();

这里我理解有一个问题
segment切换后，原来的号段没有到达maxId，这时转到新的segment，value值重新计算，会废弃掉前一个segment剩余没有用到的id。

号段模式下，多台leaf取出的ID不能趋势递增？

我们有个IM场景，需要每个会话都是趋势递增（可以不连续），但现在如果布多个leaf做不到这一点，有没有什么思路，谢谢了。

segment模式每分钟更新疑惑

我看到segment模式下每分钟都更新了cache，但在updateSegmentFromDb方法中duration与SEGMENT_DURATION比较时的SEGMENT_DURATION是十五分钟，这个怎么解释。duration在这里不可能大于1分钟。肯定是小于15分钟的。

如何拆解Leaf Snowflake UID

Leaf Snowflake是一个很棒的项目，非常感谢Leaf Snowflake的开源！

基于Leaf Snowflake生成一个UID后，我希望将各部分拆解出来，得知通过什么key，什么时间生成的ID，我需要怎么做？

谢谢！

关于snowflake的workerId

拜读了一下源码，目前workerI都是根据zk排队序号生成，大多时候为0。
这样的话根据workerId，也就不能反推出申请业务，在SnowflakeIDGenImpl的get方法中，参数key没有使用途径。
我建议workerId，其实可以由key的规则生成，这样workerId不是更有意义吗

segment模式极端情况

考虑极端情况
假设step=10,当有21个请求同时进来
1.编号1-10通过bufferA返回第二个请求去load bufferB数据
2.编号11-21进入waitAndSleep等待
3.bufferB加载完成编号11-20通过bufferB返回编号21将抛异常

fillBuffer.patch.txt

获取本机IP

com.sankuai.inf.leaf.common.Utils#getIp linux下获取到127.0.0.1

号段模式有些id被丢弃(segment切换)

发现一个问题想请教：
我DB设置的step的步长为2000，消费了27个id，然后重启应用发现，
id不是从28开始，而是直接从2001开始，（2001-27）个id被丢弃，
丢弃掉了前一个segment剩余没有用到的id。

Have you considered the problem of high concurrency in a distributed environment?

Is the code only guaranteed to be concurrent in stand-alone mode?

从数据库取数据如何保证多个服务同时取而不重复

从数据库取tag, id, step是用SQL: @select("SELECT biz_tag, max_id, step FROM leaf_alloc WHERE biz_tag = #{tag}")
但没有使用锁, 如果保证多个服务同时取而不重复呢

SnowflakeZookeeperHolder#PROP_PATH 错误

配置文件路径错误:
修正PROP_PATH :
System.getProperty("java.io.tmpdir") => System.getProperty("java.io.tmpdir") + File.separator

[WARNING]
java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:498)
at org.springframework.boot.maven.AbstractRunMojo$LaunchRunner.run (AbstractRunMojo.java:528)
at java.lang.Thread.run (Thread.java:745)
Caused by: org.springframework.boot.context.embedded.tomcat.ConnectorStartFailedException: Connector configured to listen on port 8080 failed to start
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.checkThatConnectorsHaveStarted (TomcatEmbeddedServletContainer.java:237)
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start (TomcatEmbeddedServletContainer.java:213)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer (EmbeddedWebApplicationContext.java:308)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh (EmbeddedWebApplicationContext.java:147)
at org.springframework.context.support.AbstractApplicationContext.refresh (AbstractApplicationContext.java:546)
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh (EmbeddedWebApplicationContext.java:124)
at org.springframework.boot.SpringApplication.refresh (SpringApplication.java:693)
at org.springframework.boot.SpringApplication.refreshContext (SpringApplication.java:360)
at org.springframework.boot.SpringApplication.run (SpringApplication.java:303)
at org.springframework.boot.SpringApplication.run (SpringApplication.java:1118)
at org.springframework.boot.SpringApplication.run (SpringApplication.java:1107)
at com.sankuai.inf.leaf.server.LeafServerApplication.main (LeafServerApplication.java:10)
at sun.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke (Method.java:498)
at org.springframework.boot.maven.AbstractRunMojo$LaunchRunner.run (AbstractRunMojo.java:528)
at java.lang.Thread.run (Thread.java:745)
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 51.736 s
[INFO] Finished at: 2019-03-08T10:23:55+08:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.springframework.boot:spring-boot-maven-plugin:1.5.18.RELEASE:run (default-cli) on project leaf-server: An exception occurred while running. null: InvocationTargetException: Connector configured to listen on port 8080 failed to start -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

apache.curator.version=2.6.0 这个版本不行。代码依赖的类找不到

<curator.version>4.0.1</curator.version>

打jar包有问题

无法直接运行所打的jar包

能够根据不同的业务模块生成一个业务段的id吗？？

号段模式下,为什么在updateSegmentFromDb代码里,必须先设置value,再设置max

你好,在 SegmentIDGenImpl.class 中, updateSegmentFromDb 方法里, 有一句注释, " // must set value before set max ",请问这里这样做是如何考虑的. 谢谢.

请问一下怎么配置生成的id的长度呢？

请问关于雪花算法，我看了一下默认生成的是19位的id，请问怎么控制id生成的长度呢？旧有系统有16位id的，也有22位id的，都想用id自动生成

交流一下

昨天拜读了一下你的源码，发现在snowflake中，有可能存在内存可见性问题而有一定概率导致重复

如果两个线程同时一秒内执行，1处导致重复的概率还是有的

Snowflake方式中twepoch是否应该改成配置

twepoch应该是twwiter开始部署这个项目的时间吧

目前支持高可用部署吗

我想问下目前是否支持高可用部署

生成短号

某些情况下ID号会作为参数的一部分编在二维码里，所以希望ID号能短一些。

我的想法是使用36进制进行标识。（0~~9 A~~Z）

是否可以实现一下。

snowflake 模式的疑问

1.snowflake 模式新的毫秒数时random的考虑。
2.snowflake 模式生成的id是不定长的吧？定长的话有什么方案建议么？

SegmentIDGenImpl 中 getIdFromSegmentBuffer 方法的一些疑惑

getIdFromSegmentBuffer() 在调用waitAndSleep()方法前currentSegment获取正确的value已经失败，在调用waitAndSleep()等待nextSegment完成对接DB的更新操作（如有必要）。
waitAndSleep()方法返回后，又对当前currentSegment尝试获取value。如果失败，则切换segment，下次循环中再次获取value

waitAndSlee()前后都对同一segment进行对获取value操作。这是有什么特殊含义在里面吗？

Preconditions类找不到，你的pom文件里面没有找到相关的包引用？是不是缺包

import com.google.common.base.Preconditions;

 <dependency>
                <groupId>com.google.guava</groupId>
                <artifactId>guava</artifactId>
                <version>23.0</version>
 </dependency>

你好，看代码是做了map缓存，那么如果多节点部署leaf server, 是否会得到重复的ID

SegmentIDGenImpl的getIdFromSegmentBuffer中buffer.rLock().lock()和buffer.wLock().lock()是否放到try.catch外面？

在下面代码中：
https://github.com/Meituan-Dianping/Leaf/blob/master/leaf-core/src/main/java/com/sankuai/inf/leaf/segment/SegmentIDGenImpl.java#L194

如果加锁失败的话，会无缘故地释放锁，是否考虑把加锁代码放到try ..catch外面，如下代码：

class X {
    // ...
 
    public void m() {
      lock.lock();  // block until condition holds ①
      try {
        // ... method body
      } finally {
        lock.unlock()  //  ②
      }
    }
 }

support Monotone increasing ID Monotone increasing

support Monotone increasing ID Monotone increasing feature

power by jraft

当步长设置过小的时候，程序会报错

当步长设置为50。然后运行SegmentIDGenImplTest中的测试方法，循环5000次，就会报错：
Both two segments in SegmentBuffer{key='leaf-segment-test', segments=[Segment(value:53,max:51,step:50), Segment(value:103,max:101,step:50)], currentPos=1, nextReady=false, initOk=true, threadRunning=true, step=50, minStep=50, updateTimestamp=1556434867190} are not ready!

从错误信息来看，threadRunning=true表示当前buffer正在填充数据，但是获取nextID的逻辑并没有等待数据填充完，就尝试获取导致报错

        //如果是新的ms开始
        sequence = RANDOM.nextInt(100);