Embark-Plasma Setup

Embark-Plasma is a plugin for Embark that does the following:

1. Provides Embark console commands for Plasma chain operations
2. Initialises EmbarkJS.Plasma in the console and makes these operations available in the DApp. The plugin currently only supports OMG's Samrong network and (v0.2) of the OMG SDK. The root chain is a contract on Rinkeby and the Plasma chain runs on Samrong. Chains created for development will be created in the future.

PLEASE NOTE This is completely alpha software and should not be used in a production environment.

Requirements

1. Embark ^4.1.0-beta.2

Plugin config

The Embark-Plasma plugin needs to be configured in your DApp's embark.json with four available properties. WATCHER_URL: The URL of the child chain watcher. CHILDCHAIN_URL: The child chain endpoint. CHILDCHAIN_EXPLORER_URL: Block explorer URL for the child chain. PLASMA_CONTRACT_ADDRESS: Plasma contract address. An example plugin configuration can be found below. Note the contract address is the address of the plasma contract on Rinkeby.

"plugins": {
  "embarkjs-connector-web3": {},
  "embark-omg": {
    "WATCHER_URL": "http://watcher.samrong.omg.network/",
    "CHILDCHAIN_URL": "http://samrong.omg.network/",
    "CHILDCHAIN_EXPLORER_URL": "http://quest.samrong.omg.network/",
    "PLASMA_CONTRACT_ADDRESS": "0x740ecec4c0ee99c285945de8b44e9f5bfb71eea7"
  }
},

Current limitations and known issues

1. The console commands can only be run when Embark is run in the Rinkeby environment, ie embark run rinkeby and the rinkeby enviroinment is correctly configured as described below.
2. This plugin can also be run in development configuration embark run, however the console commands will not work correctly, as they will be interfacing with a contract address on the local blockchain and not rinkeby.
3. The DApp must use Metamask. The accounts configured in the blockchain config cannot be used in the DApp. This is a limitation of Embark itself, and will hopefully be updated soon.

Available console commands

Embark console commands can be executed in an embark console (by running embark console) or in Cockpit's builtin console on the Dashboard. These commands require that Embark is set in testnet environment, on Rinkeby, and that an account with funds on Rinkeby is added to the contract account configuration (ie via mnemonic). More information about to do this can be found in Embark's documentation.

The first account configured that is not the coinbase will be used as the main account in the child chain.

An example configuration in config/contracts.js would look like:

module.exports = {
  //...
  rinkeby: {
    deployment: {
      host: "rinkeby.infura.io/v3/INFURA_API_KEY",
      port: false,
      type: "rpc",
      protocol: "https",
      accounts: [
        {
          mnemonic: "MNEMONIC_HERE",
          addressIndex: "0", // Optional. The index to start getting the address
          numAddresses: "2", // Optional. The number of addresses to get
          hdpath: "m/44'/60'/0'/0/" // Optional. HD derivation path
        }
      ]
    },
    contracts: {
      PlasmaCore: {
        address: "0x740ecec4c0ee99c285945de8b44e9f5bfb71eea7",
        abiDefinition: require("@omisego/omg-js-rootchain/src/contracts/RootChain.json").abi
      }
    },
    dappConnection: [
      "$WEB3",  // uses pre existing web3 object if available (e.g in Mist)
      "https://rinkeby.infura.io/v3/INFURA_API_KEY"
    ]
  },
  //...
}

The above configuration sets up an environment called rinkeby. To run Embark using the rinkeby environment, you would run:

embark run rinkeby

NOTE: You can still run Embark in the development environment, ie embark run, however the console commands will not work correctly. The DApp will still have access to EmbarkJS.Plasma and will still function correctly.

Init

Initialises the root and child chains and sets up web3. This is already done for us in the context of Embark, however we can re-initialise the plugin using the --force param if needed.

# plasma init [--force]
plasma init

Status

Gets the status of the child chain.

# plasma status
plasma status

Example output:
{ byzantine_events:
  [ 
    { details: [Object], event: 'unchallenged_exit' },
    { details: [Object], event: 'unchallenged_exit' },
    { details: [Object], event: 'invalid_exit' },
    { details: [Object], event: 'invalid_exit' } 
  ],
  contract_addr: '0x740ecec4c0ee99c285945de8b44e9f5bfb71eea7',
  eth_syncing: false,
  in_flight_exits: [],
  last_mined_child_block_number: 247000,
  last_mined_child_block_timestamp: 1560740479,
  last_seen_eth_block_number: 4574127,
  last_seen_eth_block_timestamp: 1560741679,
  last_validated_child_block_number: 239000,
  last_validated_child_block_timestamp: 1560431021,
  services_synced_heights:
  [ 
    { height: 4553417, service: 'block_getter' },
    { height: 4574114, service: 'challenges_responds_processor' },
    { height: 4574114, service: 'competitor_processor' },
    { height: 4574116, service: 'convenience_deposit_processor' },
    { height: 4553417, service: 'convenience_exit_processor' },
    { height: 4574116, service: 'depositor' },
    { height: 4574114, service: 'exit_challenger' },
    { height: 4553417, service: 'exit_finalizer' },
    { height: 4574114, service: 'exit_processor' },
    { height: 4553417, service: 'ife_exit_finalizer' },
    { height: 4574114, service: 'in_flight_exit_processor' },
    { height: 4574114, service: 'piggyback_challenges_processor' },
    { height: 4574114, service: 'piggyback_processor' },
    { height: 4574126, service: 'root_chain_height' } 
  ] 
}

Deposit

Deposits wei from the root chain (Rinkeby) to the child chain by sending funds to the Plasma contract on Rinkeby

# plasma deposit [amount]
plasma deposit 10000

Transfer

Transfers wei from the main child chain account to any other account on Rinkeby.

# plasma transfer [to_address] [amount]
plasma transfer 0xcc9581513771666c47b5f664024B2f47d5C08bD3 100

Exit

Exits all UTXO's from the child chain to the root chain for a particular address. Note that exits are subject to the minimum finalisation period (current 7 days). Please see the elixir-omg documentation for more information.

# plasma exit [child_chain_address]
plasma exit 0xcc9581513771666c47b5f664024B2f47d5C08bD3

EmbarkJS-Plasma

This project depends on embarkjs-plasma which extends EmbarkJS and makes convenience commands available to the DApp in the browser.

Example DApp

The embark-plasma-demo is an example DApp using this plugin. It is based on the OMG js-starter-kit, but instead uses EmbarkJS.Plasma for all its functionality.

Please report any other issues you find, thank you!