Go EtherZero

Official golang implementation of the EtherZero protocol.

Building the source

Building geth requires both a Go (version 1.10.1 or later) and a C compiler. You can install them using your favourite package manager. Once the dependencies are installed, run

make

Executables

The go-etherzero project comes with several wrappers/executables found in the cmd directory.

Running geth

Going through all the possible command line flags is out of scope here, but we've enumerated a few common parameter combos to get you up to speed quickly on how you can run your own Geth instance.

Full node on the main Etherzero network

$ geth console

Etherzero test network for development

Transitioning towards developers, if you'd like to play around with creating Etherzero contracts, you almost certainly would like to do that without any real money involved until you get the hang of the entire system. In other words, instead of attaching to the main network, you want to join the test network with your node, which is fully equivalent to the main network, but with play-Ether only.

$ geth --testnet --masternode --nodekeyhex "a9b50794ab7a9987aa416c455c13aa6cc8c0448c501a3ce8e4840efe47cb5c29" --rpc --rpcvhosts "*" --rpccorsdomain "*" console

> miner.start()

The console subcommand have the exact same meaning as above and they are equally useful on the testnet too. Please see above for their explanations if you've skipped to here.

Specifying the --testnet flag however will reconfigure your Geth instance a bit:

• Instead of using the default data directory (~/.etherzero on Linux for example), Geth will nest itself one level deeper into a testnet subfolder (~/.etherzero/testnet on Linux). Note, on OSX and Linux this also means that attaching to a running testnet node requires the use of a custom endpoint since geth attach will try to attach to a production node endpoint by default. E.g. geth attach <datadir>/testnet/geth.ipc. Windows users are not affected by this.
• Instead of connecting the main Etherzero network, the client will connect to the test network, which uses different P2P bootnodes, different network IDs and genesis states.

Note: Although there are some internal protective measures to prevent transactions from crossing over between the main network and test network, you should make sure to always use separate accounts for play-money and real-money. Unless you manually move accounts, Geth will by default correctly separate the two networks and will not make any accounts available between them.

Docker quick start

One of the quickest ways to get Etherzero up and running on your machine is by using Docker:

docker run -d --name etherzero-node -v /Users/alice/etherzero:/root \
           -p 9646:9646 -p 21212:21212 \
           Etherzero/client-go

This will start geth in fast-sync mode with a DB memory allowance of 1GB just as the above command does. It will also create a persistent volume in your home directory for saving your blockchain as well as map the default ports. There is also an alpine tag available for a slim version of the image.

Do not forget --rpcaddr 0.0.0.0, if you want to access RPC from other containers and/or hosts. By default, geth binds to the local interface and RPC endpoints is not accessible from the outside.

Programatically interfacing Geth nodes

As a developer, sooner rather than later you'll want to start interacting with Geth and the Etherzero network via your own programs and not manually through the console. To aid this, Geth has built-in support for a JSON-RPC based APIs (standard APIs and Geth specific APIs). These can be exposed via HTTP, WebSockets and IPC (unix sockets on unix based platforms, and named pipes on Windows).

The IPC interface is enabled by default and exposes all the APIs supported by Geth, whereas the HTTP and WS interfaces need to manually be enabled and only expose a subset of APIs due to security reasons. These can be turned on/off and configured as you'd expect.

HTTP based JSON-RPC API options:

• --rpc Enable the HTTP-RPC server
• --rpcaddr HTTP-RPC server listening interface (default: "localhost")
• --rpcport HTTP-RPC server listening port (default: `9646)
• --rpcapi API's offered over the HTTP-RPC interface (default: "eth,net,web3")
• --rpccorsdomain Comma separated list of domains from which to accept cross origin requests (browser enforced)
• --ws Enable the WS-RPC server
• --wsaddr WS-RPC server listening interface (default: "localhost")
• --wsport WS-RPC server listening port (default: 8546)
• --wsapi API's offered over the WS-RPC interface (default: "eth,net,web3")
• --wsorigins Origins from which to accept websockets requests
• --ipcdisable Disable the IPC-RPC server
• --ipcapi API's offered over the IPC-RPC interface (default: "admin,debug,eth,miner,net,personal,shh,txpool,web3")
• --ipcpath Filename for IPC socket/pipe within the datadir (explicit paths escape it)

You'll need to use your own programming environments' capabilities (libraries, tools, etc) to connect via HTTP, WS or IPC to a Geth node configured with the above flags and you'll need to speak JSON-RPC on all transports. You can reuse the same connection for multiple requests!

Note: Please understand the security implications of opening up an HTTP/WS based transport before doing so! Hackers on the internet are actively trying to subvert Etherzero nodes with exposed APIs! Further, all browser tabs can access locally running webservers, so malicious webpages could try to subvert locally available APIs!

Operating a private network

Maintaining your own private network is more involved as a lot of configurations taken for granted in the official networks need to be manually set up.

Defining the private genesis state

First, you'll need to create the genesis state of your networks, which all nodes need to be aware of and agree upon. This consists of a small JSON file (e.g. call it genesis.json):

{
  "config": {
        "chainId": 0,
        "homesteadBlock": 0,
        "eip155Block": 0,
        "eip158Block": 0
    },
  "alloc"      : {},
  "coinbase"   : "0x0000000000000000000000000000000000000000",
  "difficulty" : "0x20000",
  "extraData"  : "",
  "gasLimit"   : "0x2fefd8",
  "nonce"      : "0x0000000000000042",
  "mixhash"    : "0x0000000000000000000000000000000000000000000000000000000000000000",
  "parentHash" : "0x0000000000000000000000000000000000000000000000000000000000000000",
  "timestamp"  : "0x00"
}

The above fields should be fine for most purposes, although we'd recommend changing the nonce to some random value so you prevent unknown remote nodes from being able to connect to you. If you'd like to pre-fund some accounts for easier testing, you can populate the alloc field with account configs:

"alloc": {
  "0x0000000000000000000000000000000000000001": {"balance": "111111111"},
  "0x0000000000000000000000000000000000000002": {"balance": "222222222"}
}

With the genesis state defined in the above JSON file, you'll need to initialize every Geth node with it prior to starting it up to ensure all blockchain parameters are correctly set:

$ geth init path/to/genesis.json

Creating the rendezvous point

With all nodes that you want to run initialized to the desired genesis state, you'll need to start a bootstrap node that others can use to find each other in your network and/or over the internet. The clean way is to configure and run a dedicated bootnode:

$ bootnode --genkey=boot.key
$ bootnode --nodekey=boot.key

With the bootnode online, it will display an enode URL that other nodes can use to connect to it and exchange peer information. Make sure to replace the displayed IP address information (most probably [::]) with your externally accessible IP to get the actual enode URL.

Note: You could also use a full fledged Geth node as a bootnode, but it's the less recommended way.

Starting up your member nodes

With the bootnode operational and externally reachable (you can try telnet <ip> <port> to ensure it's indeed reachable), start every subsequent Geth node pointed to the bootnode for peer discovery via the --bootnodes flag. It will probably also be desirable to keep the data directory of your private network separated, so do also specify a custom --datadir flag.

$ geth --datadir=path/to/custom/data/folder --bootnodes=<bootnode-enode-url-from-above>

Note: Since your network will be completely cut off from the main and test networks, you'll also need to configure a miner to process transactions and create new blocks for you.

Running a private miner

Mining on the public Etherzero network is a complex task as it's only feasible using GPUs, requiring an OpenCL or CUDA enabled ethminer instance. For information on such a setup, please consult the EtherMining subreddit and the Genoil miner repository.

In a private network setting however, a single CPU miner instance is more than enough for practical purposes as it can produce a stable stream of blocks at the correct intervals without needing heavy resources (consider running on a single thread, no need for multiple ones either). To start a Geth instance for mining, run it with all your usual flags, extended by:

$ geth <usual-flags> --mine --minerthreads=1 --etherbase=0x0000000000000000000000000000000000000000

Which will start mining blocks and transactions on a single CPU thread, crediting all proceedings to the account specified by --etherbase. You can further tune the mining by changing the default gas limit blocks converge to (--targetgaslimit) and the price transactions are accepted at (--gasprice).

License

The go-ethereum library (i.e. all code outside of the cmd directory) is licensed under the GNU Lesser General Public License v3.0, also included in our repository in the COPYING.LESSER file.

The go-ethereum binaries (i.e. all code inside of the cmd directory) is licensed under the GNU General Public License v3.0, also included in our repository in the COPYING file.