devchain v0.0.4

devchain

Private Ethereum blockchain creator and development geth server

With devchain you can easily create your own private Ethereum blockchains and private networks. The setup needed is abstracted away, and you can create multiple private blockchains in seconds!

devchain is great for development because you can adjust mining difficulty and keep your blockchain state over multiple sessions, Plus, since you're using a real geth node, production release on geth will be a breeze! You can also quickly set up your own private networks to test on.

Additionally, a Javascript file is preloaded into geth that gives you a ton of useful features. It automates account creation, distributing Ether to your accounts, and mining for transactions. It also displays transaction info and contains an object (dev) containing helper methods such as showing account balances and transferring Ether between your accounts.

Install

You must install geth to use devchain.

After that install devchain:

npm install -g devchain

Usage

Initialize

Go to the directory where you'll like devchain to be and in your terminal at type:

-> devchain

The first time you use the command it will initialize devchain.

This will create a folder called devchain/, a file called devgenesis.json, and a file called devconfig.js. The folder will contain your Ethereum blockchain data such as blocks and accounts. The file devgenesis.json is your blockchain's genesis file, which contains the data for the blockchain's first block. Go here to learn more about the genesis file.

The genesis file's most useful property is the "difficulty". The difficulty refers to how fast new blocks can be mined. You can set a low difficulty for development purposes or a high difficulty to mimic actual production.

The file devconfig.js lets you adjust the options of the geth preload script and the geth server options. The default options are shown below. All command options will overwrite the config file's expect staticNodes, which gets added on instead.

{
  /** Preload script options */
  autoMine: true, // Set false to turn off auto mining
  isMute: false, // Set true to turn off transaction receipt display
  accountAmount: 5, // Number of accounts to create
  password: ' ', // Password to create accounts with
  minAmount: 50, // Ether amount to keep coinbank topped off at
  distributeAmount: 10, // Ether amount to distribute to all accounts
  blocks: 5, // Additional blocks to mine after auto mining a transaction

  /** Custom geth node start options */
  rpcaddr: 'localhost', // RPC host
  rpcport: 8545, // RPC port
  port: 30303, // P2P network listening port
  networkid: 1, // Network identifier. To connect with other nodes
  staticNodes: [] // Geth enode addresses to connect with
}

Adjust devgenesis.json and devconfig.js as needed.

Start

Call the devchain command again to start up the geth server. If there's no blockchain data it will initialize a new blockchain based on devgenesis.json.

If you wish to have a set of accounts all preallocated with Ether wait until the initial setup actions are completed. Setup actions can be adjusted from devconfig.js or thru command options. If you set your own password you will need to leave it inside the config file or remember it for next time to pass in as an option.

By default the geth server will create 3 accounts and automatically start mining. 10 Ether will be distributed from your coinbase (first account created) to all other accounts after 31 Ether is reached. It will then mine 50 Ether and wait for pending transactions before mining again, or to keep the coinbase topped off.

Ether will only be distributed to all accounts on a new blockchain geth start. To disable this feature turn off auto mining with the option --off. You can turn auto mining back on with the geth console's dev object.

Console helper methods

In the geth console you're given access to an object called dev. The methods are shown below. These methods are also shown upon starting up the geth server or by using dev.help().

• dev
  • .minAmount - Adjust the minimum amount of Ether to keep above
  • .accounts() - Displays all accounts, balances, and indexes
  • .auto() - Toggles auto mining
  • .start(threads) - Start mining -- threads defaults to 1
  • .stop() - Stop mining
  • .transfer(fromIndex, toIndex, etherAmount) - Transfer Ether between your accounts
  • .distribute(fromIndex, etherAmount) - Distribute Ether to all your accounts from one account
  • .mine(blockAmount) - Mine a certain amount of blocks -- blockAmount defaults to 1
  • .block(blockNumber) - Display block information -- blockNumber defaults to latest
  • .coinbase(accountIndex) - Change coinbase
  • .mute() - Toggles transaction receipt display
  • .help() - Display dev methods

Connection

The geth option to enable an RPC connection, --rpc, is used by default. The connection listens at the address and port that you set. The default is localhost:8545. To turn off the RPC connection use the option --rpcoff.

Reset

To reset your blockchain data and accounts use:

-> devchain --reset

This will create a new devchain/ folder and if the devgenesis.json exists in the current directory it will start up a new blockchain.

Connecting with other blockchains

To connect with other blockchains you will need the geth enode addresses you wish to connect with. The other blockchains will need to have the same genesis file and be using the same network id as you. Your enode address is shown when you start the geth server.

You can pass in static nodes with the command option --staticnodes or you can add them into the devconfig.js staticNodes property. For new blockchains it creates a static-nodes.json file within your blockchain folder, otherwise it connects them within geth. Go here to learn more about static nodes and connecting to peers.

The geth option --nodiscover is used by default so only people who manually add you will be able to find you. Use the option --nodiscoveroff to disable it.

To connect with nodes running on the network id 1000:

-> devchain --staticnodes enode://pubkey1@ip:port,enode://pubkey2@ip:port --networkid 1000

You can create multiple private blockchains running on your computer by giving them an unique RPC port, network p2p port, and blockchain data location.

The default ports opened:

-> devchain --rpcport 8545 --port 30303

Or with the shorthand options:

-> devchain -p 8545 -n 30303

You can specify a custom path to the blockchain data. Alternatively you can go to that directory to call the command.

-> devchain --datadir './relative/path/to/chaindata' --rpcport 8546 --port 30304

Options

All command options will overwrite the devconfig.js options except --staticnodes, which gets added on instead.

devchain -r --reset, --off, --mute, -a --accounts <number>, -t --distribute <number>, -w --password <value>, -b --blocks <number>, -d --datadir <path>, -h --rpcaddr <value>, -p --rpcport <number>, -n --port <number>, --networkid <number>, --rpcoff, --nodiscoveroff, -s --staticnodes <enodes>

Options             Type          Description

-r --reset           --           Reset blockchain data
--off                --           Turn off auto mine
--mute               --           Turn off transaction receipt display
-a --accounts        <number>     Number of accounts to initially create. Default is 3
-t --distribute      <number>     Ether amount to distribute to accounts initially. Default is 10
-w --password        <value>      Password to give and unlock the accounts created. Default is ""
-b --blocks          <number>     Additional blocks to mine after auto mining a transaction
-d --datadir         <path>       Relative path to blockchain data
-h --rpcaddr         <value>      Geth server HTTP-RPC addr. Default is 'localhost'
-p --rpcport         <number>     Geth server HTTP-RPC port. Default is 8545
-n --port            <number>     Geth server network p2p port. Default is 30303
--networkid          <number>     Geth network identifier. To connect with other nodes. Default is 1
--rpcoff             --           Disable the Geth RPC connection. Don't set `--rpc` option for geth
--nodiscoveroff      --           Don't set `--nodiscover` option for geth
-s --staticnodes     <enodes>     Comma separated list with no spaces of static nodes to connect with.
                                  This will create a static-nodes.json file within your blockchain's data directory for new blockchains

You can pass in additional options that aren't listed for geth. You can also do this via devconfig.js as additional properties. The key will be the option name with the '--' removed. If your desired option doesn't require a value, set it as true. An example is shown below:

{
  ipcdisable: true,
  ipcapi: 'admin, eth, personal, web3',
  fast: true
}

Support

If you found devchain useful please leave a star on GitHub or give feedback!