edu-chain :: Instructional Blockchain

educhain is an instructional purpose blockchain.
#blockchain #simulator #testing-tools #test-automation

The 6th D2 CAMPUS FEST Finalists
The main project of Sogang Univ. Blockchain Lab.
Based on one-chain
Based on blockchain-simulator

Overview

Fill in the blanks, simulate your own code, check the score, and improve it.
Make your own blockchain core.

It was created at Sogang University's Blockchain Lab. by Luke Park (Sanghyeon Park).

educhain is a simple blockchain implementation for instructional and educational purpose. Like Pintos, simple operating system framework for the 80x86 architecture, educhain project is intended to introduce undergraduates to concepts in blockchain core design and implementation.

The simulator written in python automatically tests your code(s) and provides you some important information.
There are some examples of important information...

• Reorganization ratio.
• Effective throughput and nodes behind ratio.
• TPS(Transactions Per Seconds).

educhain version 2.0.0 targets a more general blockchain implementation. Now students can implement the blockchain core in various ways. For example, you can implement a consensus algorithm in PoW(Proof-of-Work), PoS(Proof-of-Stake), and PoA(Proof-of-authority); whatever you want. Not only consensus parts, but also block or blockchain structure, validation processes, communication parts, and identification.

Get educhain version 1.0.0 at v1.0.0 branch.

Problem Solving

• Goto the problem branch
  • Q1: Consensus Algorithm
• Goto the solution branch

How to Use

Click on the image above to play the video.

Environments

Blockchain core and its accompanying parts are written in Node.js. Testing or simulating parts are written in Python.

• Node.js v8.11.3 (>=4.3.2)
• Python 3.6.7

Start a Simulation

Preconditions

$ sh preconditions.sh

Run

$ sh run.sh

or

$ python3 main.py --nodes=24 --neighbors=3

There are several arguments that control simulation settings.

$ python3 main.py --help
  --steps STEPS         The number of simulation steps.
  --nodes NODES         The number of full nodes constructing blockchain.
  --neighbors NEIGHBORS
                        Each node initiates links to the amount of 'neighbors'
                        selected neighbors.
  --timeout TIMEOUT     Maximum waiting time. (seconds)
  --prop_delay_avg PROP_DELAY_AVG
                        The average value of propagation delay. (milliseconds)
  --prop_delay_std PROP_DELAY_STD
                        The standard deviation of propagation delay.
                        (milliseconds)
  --freq_avg FREQ_AVG   The average value of frequency. (milliseconds)
  --freq_std FREQ_STD   The standard deviation of frequency. (milliseconds)
  --master_http MASTER_HTTP
                        The HTTP port of a master node.
  --master_p2p MASTER_P2P
                        The P2P port of a master node.
  --https HTTPS         The base number of HTTP ports.
  --p2ps P2PS           The base number of P2P ports.

Cleanup

$ sh cleanup.sh

APIs

Get blockchain

curl http://127.0.0.1:3001/blocks

You can pretty-print JSON with:

curl http://127.0.0.1:3001/blocks | python -m json.tool

Python >= 2.6 required.

Get connected peers

curl http://127.0.0.1:3001/peers

Get Address

curl http://127.0.0.1:3001/address

Trouble Shootings

• if ImportError: No module named requests occurs:

$ pip install requests

• if Error: listen EADDRINUSE :::3001 occurs:

$ killall npm

• if 'Time out' occurs:

$ sh preconditions.sh

References

• https://github.com/twodude/onechain
• https://github.com/twodude/blockchain-simulator
• https://web.stanford.edu/class/cs140/projects/pintos/pintos.html#SEC_Top

License

The educhain project is licensed under the Apache License, Version 2.0, also included in our repository in the LICENSE file.