smartcontracts/plasma-mvp

Plasma MVP

We're implementing Minimum Viable Plasma. This repository represents a work in progress and will undergo large-scale modifications as requirements change.

Overview

Plasma MVP is split into four main parts: root_chain, child_chain, client, and cli. Below is an overview of each sub-project.

root_chain

root_chain represents the Plasma contract to be deployed to the root blockchain. In our case, this contract is written in Solidity and is designed to be deployed to Ethereum. root_chain also includes a compilation/deployment script.

RootChain.sol is based off of the Plasma design specified in Minimum Viable Plasma. Currently, this contract allows a single authority to publish child chain blocks to the root chain. This is not a permanent design and is intended to simplify development of more critical components in the short term.

child_chain

child_chain is a Python implementation of a Plasma MVP child chain client. It's useful to think of child_chain as analogous to Parity or Geth. This component manages a store of Blocks and Transactions that are updated when events are fired in the root contract.

child_chain also contains an RPC server that enables client interactions. By default, this server runs on port 8546.

client

client is a simple Python wrapper of the RPC API exposed by child_chain, similar to Web3.py for Ethereum. You can use this client to write Python applications that interact with this Plasma chain.

cli

cli is a simple Python application that uses client to interact with child_chain, via the command line. A detailed documentation of cli is available here.

Getting Started

Dependencies

This project has a few pre-installation dependencies.

LevelDB

Mac:

brew install leveldb

Linux:

LevelDB should be installed along with plyvel once you make the project later on.

Windows:

First, install vcpkg. Then,

vcpkg install leveldb

Solidity

Mac:

brew update
brew upgrade
brew tap ethereum/ethereum
brew install solidity

Linux:

sudo add-apt-repository ppa:ethereum/ethereum
sudo apt-get update
sudo apt-get install solc

Windows:

Follow this guide

Python 3.2+

Mac:

brew install python

Linux:

sudo apt-get install software-properties-common
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt-get update
sudo apt-get install python3

Windows:

choco install python

Installation

Note: we optionally recommend using something like virtualenv in order to create an isolated Python environment:

$ virtualenv env -p python3

Fetch and install the project's dependencies with:

$ make

Testing

Before you run tests, make sure you have an Ethereum client running and an JSON RPC API exposed on port 8545. We recommend using ganache-cli to accomplish this when running tests.

Project tests can be found in the tests/ folder. Run tests with:

$ make test

If you're contributing to this project, make sure you also install flake8 and lint your work:

$ make lint

Starting Plasma

The fastest way to start playing with our Plasma MVP is by starting up ganache-cli, deploying everything locally, and running our CLI. Full documentation for the CLI is available here.

$ ganache-cli -m=plasma_mvp # Start ganache-cli
$ make root-chain           # Deploy the root chain contract
$ make child-chain          # Run our child chain and server

CLI Documentation

omg is a simple Plasma CLI that enables interactions with the child chain. Full documentation is provided below.

help

Description

Shows a list of available commands.

Usage

help

deposit

Description

Creates a deposit transaction and submits it to the child chain.

Usage

deposit <amount> <address>

Example

deposit 100 0xfd02ecee62797e75d86bcff1642eb0844afb28c7

sendtx

Description

Creates a transaction and submits it to the child chain.

Usage

sendtx <blknum1> <txindex1> <oindex1> <blknum2> <txindex2> <oindex2> <newowner1> <amount1> <newowner2> <amount2> <fee> <key1> [<key2>]

Example

send_tx 1 0 0 0 0 0 0xfd02ecee62797e75d86bcff1642eb0844afb28c7 50 0x4b3ec6c9dc67079e82152d6d55d8dd96a8e6aa26 45 5 3bb369fecdc16b93b99514d8ed9c2e87c5824cf4a6a98d2e8e91b7dd0c063304

submitblock

Description

Signs and submits the current block to the root contract.

Usage

submitblock <key>

Example

submitblock 3bb369fecdc16b93b99514d8ed9c2e87c5824cf4a6a98d2e8e91b7dd0c063304

withdraw

Description

Creates an exit transaction for the given UTXO.

Usage

withdraw <blknum> <txindex> <oindex> <key1> [<key2>]

Example

withdraw 1000 0 0 3bb369fecdc16b93b99514d8ed9c2e87c5824cf4a6a98d2e8e91b7dd0c063304

withdrawdeposit

Description

Withdraws from a deposit.

Usage

withdrawdeposit 0xfd02ecee62797e75d86bcff1642eb0844afb28c7 1 100

CLI Example

Let's play around a bit:

1. Deploy the root chain contract and start the child chain as per Starting Plasma.

2. Start by depositing:

omg deposit 100 0xfd02ecee62797e75d86bcff1642eb0844afb28c7

3. Send a transaction:

omg sendtx 1 0 0 0 0 0 0xfd02ecee62797e75d86bcff1642eb0844afb28c7 50 0x4b3ec6c9dc67079e82152d6d55d8dd96a8e6aa26 45 5 3bb369fecdc16b93b99514d8ed9c2e87c5824cf4a6a98d2e8e91b7dd0c063304

4. Submit the block:

omg submitblock 3bb369fecdc16b93b99514d8ed9c2e87c5824cf4a6a98d2e8e91b7dd0c063304

5. Withdraw the original deposit (this is a double spend!):

omg withdrawdeposit 0xfd02ecee62797e75d86bcff1642eb0844afb28c7 1 100

Note: The functionality to challenge double spends from the cli is still being worked on.