yeqown / cassem

(WIP) A distributed Configuration Center Application.

Hi, This is yeqown

Welcome to my GitHub profile! I'm a backend software engineer from China 🇨🇳, and I'm trying to be a full-stack engineer and a DevOps engineer. I'd like to contribute to open source projects and share my knowledge with others.

About me

• 🎓 Education: Computer Science and Technology, SouthWest Petroleum University
• 🌱 Focusing on (now): openresty, lua, LSM, k8s, service mesh
• 💬 Topics I like: Microservices, DevOps, Distributed Systems, Linux, Open Source, etc. We can talk these topics together.

Skills

• Languages: go, python, shell, javascript, c, lua, etc.
• Frameworks and Libraries: kratos, gin, gorm, asynq etc.
• Network: tcp/ip, http1/2, grpc, ICMP, etc.
• Tools: redis, kafka, mysql, rabbitmq, openresty/nginx, k8s, etc.
• Other Skills: performance tuning, distributed systems design, CI/CD, etc.

I'd using these skills to build a distributed system, and I'm trying to learn more about distributed systems design and implementation.

Open Source Projects

I'd like to contribute to open source projects, you can find them in my GitHub repositories. Such as:

• kratos - A Go framework for microservices.
• go-gorm - The fantastic ORM library for Golang, aims to be developer friendly.
• asynq - Asynq: simple, reliable, and efficient distributed task queue in Go.
• gocache - A complete Go cache library that brings you multiple ways of managing your caches.
• go-qrcode - A golang lib to generate QRCode.

Recent Targets or Plans

I'm trying to do these things recently:

• Implement a KV storage
• Learning openresty/nginx skills deeply
• Studying lua
• More distributed systems design
• Distributed Theory
• Linux kernel and OS design

Contact me

You can find and get touch with me on these accounts!

• GitHub: https://github.com/yeqown
• Email: [email protected]
• Social Contact：twitter, TG

If you interested in my projects, you can get in touch with me to discuss more details.

Thanks for visiting my GitHub profile and have a nice day!

cassem's Issues

move `cache` instance from `core.Core`

For now, cache is held by the core.Core, but the cache component is mainly used in the raft.FSM. To close up all of the cache component entries, so move it into FSMWrapper maybe make it cleraly to read.

CI: fill the CI procedure

• auto run tests
• auto build images
• auto publish images

optimize join action

Background

cassemd must get leader address so that it could join to cluster successfully, this is not easy to use and is unreasonable.

Solution

• forward join request to the leader while a slave node receives a join request
• allow cassemd to receive an array of node address so that it could try to join one by one.

optimise bbolt repository implementation or use another KV persistence

RT

replace cache implementation with LRU-K(2) replacement algorithm

now cache components are implemented by go built-in map, it's too simple to manage caches. So that cassemd needs a new version of the cache component to manage caches.

The duty of the cache component includes:

// IStore required ICache to implement persist and restore functions so that the cache could be
// save into file and restore from that.
type IStore interface {
	// Persist serializes cache into []byte data.
	Persist() ([]byte, error)

	// Restore apply data to override all the cache data, data is coming from Persist.
	Restore(data []byte) error
}

// ICache represents the proxy to operate cache data,
// also need to replace data while cache size is over it's limits.
type ICache interface {
	IStore

	// Set returns wasSet means this key needs to synchronous, err means set failed.
	Set(key string, v []byte) SetResult

	// Get
	Get(key string) ([]byte, error)

	// Del if any error is returned, core.Core would not trigger synchronous of the cache.
	Del(key string) SetResult
}

// SetResult represents what operations would be caused by ICache.Set, operations include:
//
// 1. NeedSync tells users that them should trigger setting apply.
// 2. NeedDeleteKey should be set while Cache-Replacing happened or core need to delete cache by itself.
//
type SetResult struct {
	err           error
	NeedSync      bool
	NeedDeleteKey string
}

Remove pair concepts from cassem

• Redesign the concepts of config container.
• Focus on the edge problems in the situation of config center.
• The reuse of pair maybe not the main issue on which the config center should take care.

REFACTOR: cassemdb bootstrap procedure refactoring

Now, cassemdb bootstrapped with fixed configuration of cassemdb cluster and it's members. But it should be another way:

1. root node1 bootstrap or recover the cluster.
2. node-2 to node-n join to the cluster which contains node1 only.

persistence refactor

Background

Need a distributed persistence component to support what helps cassem become a system satisfied CP and provide available as much as possible. On another way, DO NOT want to import another dependency to make the save procedure complicated.

Risk

What is a risk is that would changes the cassem software architecture, even makes HTTP API changes.

Thoughts

bbolt would be used to replace mysql.

implement permission controller

plan to use casbin library

replacing raft library

using etcd-io/etcd/raft instead of github.com/hashicorp/raft

develop `cassemctl` command

features:

1. genconf generates the default config file for users.
2. migrate command to initialize persistence component (for now, DB support).
3. basic resource managing commands (CURD) + watch. Maybe, this would build on the client SDK ...
4. health diagnosis (TODO). metrics and cluster infos.