Leaf key generator implementation for Apache ShardingSphere

[tristaZero]

Modifying API of generating gobally unique ID, and providing alternatives of gobally unique ID generator for users now is ongoing.

To meet users' different needs and make the module of globally unique ID key generator more powerful, we plan to implement Leaf key generator for ShardingSphere.

Welcome @Zhaodong Xie, the author of Leaf, to contribute to Apache ShardingSphere. He will be in charge of Leaf key generator implementation for Apache ShardingSphere.

[1] https://tech.meituan.com/MT_Leaf.html

[Yaccc]

assign to me? @terrymanu

[terrymanu]

Cannot assign issue if your account is not in apache LDAP.
Please just submit pull request anyway. :)

[wgy8283335]

@tristaZero. @terrymanu. I'd like to take the issue. Could you make an explanation of the new feature? Is it means creating a new generator which implements ShardingKeyGenerator in 'org.apache.shardingsphere.core.keygen.impl' package?

[terrymanu]

Yes, you can reference https://tech.meituan.com/MT_Leaf.html

[wgy8283335]

@terrymanu. I've read the reference. There are two kinds of generators in the leaf. One is leaf-segment and another is leaf-snowflake. I'd like to start with leaf-segment. The leaf-segment algorithm needs a third component to recode the latest id segment. The third component could be a database or zookeeper. I prefer to choose zookeeper to recode the latest id segment. Because, if id segments stored in a database, a conflit may happen when the table name of id segment is the same as another table of service. Another reason for using zookeeper, is that the zookeeper is necessary for leaf-snowflake. So, do you have any suggestion for me?

[terrymanu]

Start from leaf-segment and use zookeeper t store for id segment is good idea.

[wgy8283335]

@terrymanu. Thank you. I've got it.

[Yaccc]

Is a bad idea！

[wgy8283335]

@Yaccc, why？

[wgy8283335]

@terrymanu. These days I've been reading through the source code of the key generator and registry center related. I'd like to discuss with you at the plan of coding leaf generator.

1. As you know the leaf generator needs zookeeper client to communicate with zookeeper server. So the way of initializing the zookeeper client is a little hard to decide. Although, initializing the client and the definition of the client has been implemented in 'package org.apache.shardingsphere.orchestration.reg'. But it is hard to use them directly,.Beacuse the key generator is in 'package org.apache.shardingsphere.core.strategy.keygen'. So I'm planning to write these part on my own to initialize the client and the related functions.
2. The property of the leaf segment generator, especially zookeeper client related.I'd like to use new parameter，this means orchestration register related parameter won't be used.
   These two points are what I like to discuss with you, do you have any suggestion?

[terrymanu]

@wgy8283335 Thank you for pay attention on this issue.

1. As you know the leaf generator needs zookeeper client to communicate with zookeeper server. So the way of initializing the zookeeper client is a little hard to decide. Although, initializing the client and the definition of the client has been implemented in 'package org.apache.shardingsphere.orchestration.reg'. But it is hard to use them directly,.Beacuse the key generator is in 'package org.apache.shardingsphere.core.strategy.keygen'. So I'm planning to write these part on my own to initialize the client and the related functions.

I prefer the agree your point, because reg module is for orchestration only, not for sharding-core, so just copy some core codes to leaf plugin is fine.

2. The property of the leaf segment generator, especially zookeeper client related.I'd like to use new parameter，this means orchestration register related parameter won't be used.

Yes, it should use new parameters, and we can put them to properties to let leaf plugin to read them.