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DHT (beta)

Overview

• A DHT can be viewed as a dictionary service distributed over a network: it provides access to a common shared key->value data-store, distributed over participating nodes with great performance and scalability.
• From a user perspective, a DHT essentially provides a map interface, with two main operations: put(key, value) and get(key). Get will retrieve values stored at a certain key while put (often called announce) will store a value on the network. Note that many values can be stored under the same key.
• There are many algorithms to implement dht, where Kademlia DHT algorithm requires to contact only O(log(N)) nodes for a get operation, N being the number of nodes in the network. This property makes DHTs very scalable as demonstrated.

Mor info in Wiki:DHT

Target

• Use go-lang to implement a DHT with basic functions
• Use this DHT to implement an easy application

Syllabus

Schedule

• Learn about Golang and at least one DHT protocol

  Project 1(Not constrained): get close to golang: implement a client-server protocol using golang. With naive tests. forward message and mutli-threads(2 with client and server)

• Implement a DHT protocol in Go

  Project 2: implement DHT: using any one model is allowed. With naive and strong tests. E.g. chatroom, torrent, dht-filesystem.

• Build a higher level application on top of your DHT

  Project 3*: implement an application. No test.

• Bonus:

  **Project 4***implement DHT with another algorithm (as mentioned above in overview), or optimize your application.

Reference

• Learn Go

A Tour of Go
Go package docs
Books about Go

• DHT models

Chord
Pastry
Kademlia

• Related project framework

Dixie
CMU
MIT

Test(beta)

Range

• nodes in DHT network >= 50
• <key, value> in DHT network >= 1500
• Give some time for your network to resume stable.

Contents

Requirements

(1) Implement this interface in interface.go

type dhtNode interface {
    Get(k string) (string, bool)
	Put(k string, v string) bool
	Del(k string) bool
	Run(wg *sync.WaitGroup)
	Create()
	Join(addr string) bool
	Quit()
	Ping(addr string) bool
}

(2) Overwrite in userdef.go NewNode()

Tests

• standard test

  get, put, del, join, quit, ping

• standard test of additive functions

  append info in <k, v>
  del_append info in <k,v>

• additive test

  get, put, del, join, quit, ping
  force quit
  load(max nodes and max data)
  unstable put and get
  mixed put, get, join, quit

Score

• 10% - learn go of navie protocol
• 60% - DHT tests
• 30% - Applications with stable network