ethereum

README

Go eFSN

FUSION would like to extend its gratitude to the Ethereum Foundation. FUSION has used the official open-source golang implementation of the Ethereum protocol.

Automatic node setup

The fastest way to get a node up and running and to start staking automatically is by using the FUSION Node Manager script.
Just execute the following command on Ubuntu 18.04 (or newer), press 1 and answer the questions:

bash -c "$(curl -fsSL https://raw.githubusercontent.com/FUSIONFoundation/efsn/master/QuickNodeSetup/fsnNode.sh)"

The Node Manager script and an example video can also be found under this link: Quick Setup
The video shows how to quickly setup a staking node.

Manual node setup

How to run a Miner

Change the parameter YOURDIRECTORY to your local directory

Install Docker first, e.g. on Ubuntu do sudo apt-get install docker.io

Pull Miner image from repository

docker pull fusionnetwork/efsn:latest

Run a Miner from the image

1. With ticket auto-buy disabled

docker run -it -p 40408:40408 -v YOURDIRECTORY:/fusion-node fusionnetwork/efsn -u <account to unlock> -e MyFusionMiner

1. With ticket auto-buy enabled

docker run -it -p 40408:40408 -v YOURDIRECTORY:/fusion-node fusionnetwork/efsn -u <account to unlock> -e MyFusionMiner -a

Build your own Miner image (optional)

docker build --file Dockerfile -t YOUR-DOCKER-HUB-ID/efsn .

Run a Miner using your image

docker run -it -p 40408:40408 -v YOURDIRECTORY:/fusion-node fusionnetwork/efsn -u <account to unlock> -e MyFusionMiner -a

Remember to:

1. Replace YOUR-DOCKER-HUB-ID with your valid Docker Hub id.

2. Save the keystore file as YOURDIRECTORY/UTC...

3. Save the password.txt as YOURDIRECTORY/password.txt

4. (Optional) Add flag "-a" or "--autobt" to enable ticket auto-buy.

5. (Optional) Add flag "-tn" or "--testnet" to connect to the public testnet.

Note: The password file must be named password.txt and the keystore file name must start with UTC...

How to run a Gateway

Change the parameter YOURDIRECTORY to your local directory

Install Docker first, e.g. on Ubuntu do sudo apt-get install docker.io

Pull Gateway image from repository

docker pull fusionnetwork/gateway:latest

Run a Gateway from the image

1. Connect to mainnet

docker run -it -p 9000:9000 -p 9001:9001 -p 40408:40408 -v YOURDIRECTORY:/fusion-node fusionnetwork/gateway

1. Connect to testnet

docker run -it -p 9000:9000 -p 9001:9001 -p 40408:40408 -v YOURDIRECTORY:/fusion-node fusionnetwork/gateway -tn

Build your own Gateway image (optional)

docker build --file Dockerfile.gtw -t YOUR-DOCKER-HUB-ID/gateway .

Run a Gateway using your image

docker run -it -p 9000:9000 -p 9001:9001 -p 40408:40408 -v YOURDIRECTORY:/fusion-node YOUR-DOCKER-HUB-ID/gateway

Remember to replace YOUR-DOCKER-HUB-ID with your valid Docker Hub id.

You can now connect to the websocket API via ws://localhost:9001

Note that this creates a public gateway, unless the system is protected by an external firewall. Additional configuration steps should be taken to ensure the security and integrity of the API communication, like setting up encryption (e.g. via an nginx proxy). To run a purely local gateway for testing, use:

docker run -it -p 127.0.0.1:9000:9000 -p 127.0.0.1:9001:9001 -p 40408:40408 -v YOURDIRECTORY:/fusion-node YOUR-DOCKER-HUB-ID/gateway

How to run a MinerAndLocalGateway

Change the parameter YOURDIRECTORY to your local directory

Install Docker first, e.g. on Ubuntu do sudo apt-get install docker.io

Pull MinerAndLocalGateway image from repository

docker pull fusionnetwork/minerandlocalgateway:latest

Run a MinerAndLocalGateway from the image

1. With ticket auto-buy disabled

docker run -it -p 127.0.0.1:9000:9000 -p 127.0.0.1:9001:9001 -p 40408:40408 -v YOURDIRECTORY:/fusion-node fusionnetwork/minerandlocalgateway -u <account to unlock> -e MyFusionMinerAndLocalGateway

1. With ticket auto-buy enabled

docker run -it -p 127.0.0.1:9000:9000 -p 127.0.0.1:9001:9001 -p 40408:40408 -v YOURDIRECTORY:/fusion-node fusionnetwork/minerandlocalgateway -u <account to unlock> -e MyFusionMinerAndLocalGateway -a

Build your own MinerAndLocalGateway image (optional)

docker build --file Dockerfile.minerLocalGtw -t YOUR-DOCKER-HUB-ID/minerandlocalgateway .

Run a MinerAndLocalGateway using your image

docker run -it -p 127.0.0.1:9000:9000 -p 127.0.0.1:9001:9001 -p 40408:40408 -v YOURDIRECTORY:/fusion-node YOUR-DOCKER-HUB-ID/minerandlocalgateway -u <account to unlock> -e MyFusionMinerAndLocalGateway

Remember to:

1. Replace YOUR-DOCKER-HUB-ID with your valid Docker Hub id.

2. Save the keystore file as YOURDIRECTORY/UTC...

3. Save the password.txt as YOURDIRECTORY/password.txt

4. (Optional) Add flag "-a" or "--autobt" to enabled ticket auto-buy.

Note: The password file must be named password.txt and the keystore file name must start with UTC...

You can now connect to the websocket API via ws://localhost:9001

API Reference

The API reference can be found here

Building from source

Building efsn requires both a Go (version 1.11 or later) and a C compiler.
You can install them using your favourite package manager.

On Ubuntu 18.04, run these commands to build efsn:

add-apt-repository ppa:longsleep/golang-backports
apt-get update
apt-get install golang-go build-essential
git clone https://github.com/FUSIONFoundation/efsn.git
cd efsn
make efsn

Executables

The FUSION project comes with a wrapper/executable found in the cmd directory.

Command	Description
efsn	Our main FUSION CLI client. It is the entry point into the FUSION network (main-, test- or private net), capable of running as a full node (default) or archive node (retaining all historical state). It can be used by other processes as a gateway into the FUSION network via JSON RPC endpoints exposed on top of HTTP, WebSocket and/or IPC transports. See efsn --help for command line options.

Running FUSION

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

Interacting with the FUSION network

By far the most common scenario is people wanting to simply interact with the FUSION network: create swaps, transfer time-locked assets; deploy and interact with contracts. To do so run

$ efsn console

This command will start up efsn's built-in interactive JavaScript console, through which you can invoke all official web3 methods as well as FUSION's own APIs.
This tool is optional; if you leave it out you can always attach to an already running efsn instance with efsn attach.

Programmatically interfacing with FUSION

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

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

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: 8545)
• --rpcapi APIs 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 APIs 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 APIs offered over the IPC-RPC interface (default: all)
• --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 an efsn 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 FUSION 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 complicated as a lot of configurations taken for granted in the official networks need to be set up manually.

Defining the private genesis state

First, you'll need to create the genesis state of your network, 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 efsn node with it prior to starting it up to ensure all blockchain parameters are correctly set:

$ efsn 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 (bootnode) 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 address to get the actual enode URL.

Note: You could also use a full fledged efsn node as a bootnode, but that is not the 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 efsn 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.

$ efsn --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.

Contribution

Thank you for considering to help out with the source code! We welcome contributions from anyone on the internet, and are grateful for even the smallest of fixes!

If you'd like to contribute to FUSION, please fork, fix, commit and send a pull request for the maintainers to review and merge into the main code base. If you wish to submit more complex changes though, please check up with the core devs first on our Telegram channel to ensure those changes are in line with the general philosophy of the project and/or get some early feedback which can make both your efforts much lighter as well as our review and merge procedures quick and simple.

Please make sure your contributions adhere to our coding guidelines:

• Code must adhere to the official Go formatting guidelines (i.e. uses gofmt).
• Code must be documented adhering to the official Go commentary guidelines.
• Pull requests need to be based on and opened against the master branch.

License

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

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

Documentation

Overview

Package ethereum defines interfaces for interacting with Ethereum.

Index

• Variables
• type CallMsg
• type ChainReader
• type ChainStateReader
• type ChainSyncReader
• type ContractCaller
• type FilterQuery
• type GasEstimator
• type GasPricer
• type LogFilterer
• type PendingContractCaller
• type PendingStateEventer
• type PendingStateReader
• type Subscription
• type SyncProgress
• type TransactionReader
• type TransactionSender

Variables

var NotFound = errors.New("not found")

NotFound is returned by API methods if the requested item does not exist.

Types

type CallMsg

type CallMsg struct {
	From     common.Address  // the sender of the 'transaction'
	To       *common.Address // the destination contract (nil for contract creation)
	Gas      uint64          // if 0, the call executes with near-infinite gas
	GasPrice *big.Int        // wei <-> gas exchange ratio
	Value    *big.Int        // amount of wei sent along with the call
	Data     []byte          // input data, usually an ABI-encoded contract method invocation
}

CallMsg contains parameters for contract calls.

type ChainReader

type ChainReader interface {
	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
	BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error)
	HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error)
	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
	TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error)
	TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error)

	// This method subscribes to notifications about changes of the head block of
	// the canonical chain.
	SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (Subscription, error)
}

ChainReader provides access to the blockchain. The methods in this interface access raw data from either the canonical chain (when requesting by block number) or any blockchain fork that was previously downloaded and processed by the node. The block number argument can be nil to select the latest canonical block. Reading block headers should be preferred over full blocks whenever possible.

The returned error is NotFound if the requested item does not exist.

type ChainStateReader

type ChainStateReader interface {
	BalanceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (*big.Int, error)
	StorageAt(ctx context.Context, account common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error)
	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
	NonceAt(ctx context.Context, account common.Address, blockNumber *big.Int) (uint64, error)
}

ChainStateReader wraps access to the state trie of the canonical blockchain. Note that implementations of the interface may be unable to return state values for old blocks. In many cases, using CallContract can be preferable to reading raw contract storage.

type ChainSyncReader

type ChainSyncReader interface {
	SyncProgress(ctx context.Context) (*SyncProgress, error)
}

ChainSyncReader wraps access to the node's current sync status. If there's no sync currently running, it returns nil.

type ContractCaller

type ContractCaller interface {
	CallContract(ctx context.Context, call CallMsg, blockNumber *big.Int) ([]byte, error)
}

A ContractCaller provides contract calls, essentially transactions that are executed by the EVM but not mined into the blockchain. ContractCall is a low-level method to execute such calls. For applications which are structured around specific contracts, the abigen tool provides a nicer, properly typed way to perform calls.

type FilterQuery

type FilterQuery struct {
	BlockHash *common.Hash     // used by eth_getLogs, return logs only from block with this hash
	FromBlock *big.Int         // beginning of the queried range, nil means genesis block
	ToBlock   *big.Int         // end of the range, nil means latest block
	Addresses []common.Address // restricts matches to events created by specific contracts

	// The Topic list restricts matches to particular event topics. Each event has a list
	// of topics. Topics matches a prefix of that list. An empty element slice matches any
	// topic. Non-empty elements represent an alternative that matches any of the
	// contained topics.
	//
	// Examples:
	// {} or nil          matches any topic list
	// {{A}}              matches topic A in first position
	// {{}, {B}}          matches any topic in first position, B in second position
	// {{A}, {B}}         matches topic A in first position, B in second position
	// {{A, B}}, {C, D}}  matches topic (A OR B) in first position, (C OR D) in second position
	Topics [][]common.Hash
}

FilterQuery contains options for contract log filtering.

type GasEstimator

type GasEstimator interface {
	EstimateGas(ctx context.Context, call CallMsg) (uint64, error)
}

GasEstimator wraps EstimateGas, which tries to estimate the gas needed to execute a specific transaction based on the pending state. There is no guarantee that this is the true gas limit requirement as other transactions may be added or removed by miners, but it should provide a basis for setting a reasonable default.

type GasPricer

type GasPricer interface {
	SuggestGasPrice(ctx context.Context) (*big.Int, error)
}

GasPricer wraps the gas price oracle, which monitors the blockchain to determine the optimal gas price given current fee market conditions.

type LogFilterer

type LogFilterer interface {
	FilterLogs(ctx context.Context, q FilterQuery) ([]types.Log, error)
	SubscribeFilterLogs(ctx context.Context, q FilterQuery, ch chan<- types.Log) (Subscription, error)
}

LogFilterer provides access to contract log events using a one-off query or continuous event subscription.

Logs received through a streaming query subscription may have Removed set to true, indicating that the log was reverted due to a chain reorganisation.

type PendingContractCaller

type PendingContractCaller interface {
	PendingCallContract(ctx context.Context, call CallMsg) ([]byte, error)
}

PendingContractCaller can be used to perform calls against the pending state.

type PendingStateEventer

type PendingStateEventer interface {
	SubscribePendingTransactions(ctx context.Context, ch chan<- *types.Transaction) (Subscription, error)
}

A PendingStateEventer provides access to real time notifications about changes to the pending state.

type PendingStateReader

type PendingStateReader interface {
	PendingBalanceAt(ctx context.Context, account common.Address) (*big.Int, error)
	PendingStorageAt(ctx context.Context, account common.Address, key common.Hash) ([]byte, error)
	PendingCodeAt(ctx context.Context, account common.Address) ([]byte, error)
	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
	PendingTransactionCount(ctx context.Context) (uint, error)
}

A PendingStateReader provides access to the pending state, which is the result of all known executable transactions which have not yet been included in the blockchain. It is commonly used to display the result of ’unconfirmed’ actions (e.g. wallet value transfers) initiated by the user. The PendingNonceAt operation is a good way to retrieve the next available transaction nonce for a specific account.

type Subscription

type Subscription interface {
	// Unsubscribe cancels the sending of events to the data channel
	// and closes the error channel.
	Unsubscribe()
	// Err returns the subscription error channel. The error channel receives
	// a value if there is an issue with the subscription (e.g. the network connection
	// delivering the events has been closed). Only one value will ever be sent.
	// The error channel is closed by Unsubscribe.
	Err() <-chan error
}

Subscription represents an event subscription where events are delivered on a data channel.

type SyncProgress

type SyncProgress struct {
	StartingBlock uint64 // Block number where sync began
	CurrentBlock  uint64 // Current block number where sync is at
	HighestBlock  uint64 // Highest alleged block number in the chain
	PulledStates  uint64 // Number of state trie entries already downloaded
	KnownStates   uint64 // Total number of state trie entries known about
}

SyncProgress gives progress indications when the node is synchronising with the Ethereum network.

type TransactionReader

type TransactionReader interface {
	// TransactionByHash checks the pool of pending transactions in addition to the
	// blockchain. The isPending return value indicates whether the transaction has been
	// mined yet. Note that the transaction may not be part of the canonical chain even if
	// it's not pending.
	TransactionByHash(ctx context.Context, txHash common.Hash) (tx *types.Transaction, isPending bool, err error)
	// TransactionReceipt returns the receipt of a mined transaction. Note that the
	// transaction may not be included in the current canonical chain even if a receipt
	// exists.
	TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error)
}

TransactionReader provides access to past transactions and their receipts. Implementations may impose arbitrary restrictions on the transactions and receipts that can be retrieved. Historic transactions may not be available.

Avoid relying on this interface if possible. Contract logs (through the LogFilterer interface) are more reliable and usually safer in the presence of chain reorganisations.

The returned error is NotFound if the requested item does not exist.

type TransactionSender

type TransactionSender interface {
	SendTransaction(ctx context.Context, tx *types.Transaction) error
}

TransactionSender wraps transaction sending. The SendTransaction method injects a signed transaction into the pending transaction pool for execution. If the transaction was a contract creation, the TransactionReceipt method can be used to retrieve the contract address after the transaction has been mined.

The transaction must be signed and have a valid nonce to be included. Consumers of the API can use package accounts to maintain local private keys and need can retrieve the next available nonce using PendingNonceAt.