ethereum

README

PulseChain Node

The repo holds the PulseChain fork of Go-Ethereum and Binance Smart Chain. Credit to the wealth of upstream development this project is built upon.

PulseChain is a stateful fork of Ethereum running Proof of Staked Authority consensus system with the stated goals of increased performance and significantly reduced fees for the users of the ecosystem. As a stateful fork, copies of all Ethereum contracts, tokens, and user accounts at time of fork will exist in the PulseChain network.

Being a fork of Go-Ethereum, many of the Go-Ethereum binaries and tools you're familiar with remain the same (geth, bootnode, puppeth, etc).

The Proof of Staked Authority (PoSA) consensus engine developed for BSC is based on the Clique consensus engine detailed in EIP-225, with validators tracking and selection being dictated by system contracts. Validator rotation on BSC is administered through cross-chain messages originating from Binance Chain. PulseChain simplifies this system by removing the dual chain complexity and by implementing validator staking and rotation as native system contracts that can be directly interacted with by the PulseChain users. Slashing logic ensures liveness, security, stability, and chain finality.

The PulseChain network will launch with a stable set of maintained validators. Tech-savvy PulseChain users are encouraged to deploy new independent validators that can be voted into the network consensus by the PulseChain users, aiding in the decentralization of the network.

Key features

Stateful Ethereum Fork

PulseChain brings all of the Ethereum state with it! As of block number _______ (TBD), Exact copies of all smart contracts, ERC-20 tokens, ERC-721 NFTs, and user accounts will exist on PulseChain. Because of the extent of applications and use cases deployed on the Ethereum mainnet, it's not possible to anticipate exactly how any cloned assets will be valued by the community. Some contracts and applications will work 100% as they do on Ethereum, other contracts such as centralized stable coins are unlikely to have the authoritative support behind them.

Eventually the relative value of these assets will equalize though market action, but it is expected that there will be a discovery period with high volatility at launch of the network.

Proof of Staked Authority

Although Proof-of-Work (PoW) has been proven as a mechanism to implement a decentralized network, it is not practical for new or small networks and requires a large number of participants and computational waste to maintain the security.

Proof-of-Authority(PoA) provides defense against 51% attack, with improved efficiency and tolerance to certain levels of Byzantine players (malicious or hacked). The PoA protocol however is most criticized for being not as decentralized as PoW, as the validators, i.e. the nodes that take turns to produce blocks, have all the authorities and are prone to corruption and security attacks.

Other blockchains, such as EOS and Cosmos both, introduce different types of Deputy Proof of Stake (DPoS) to allow the token holders to vote and elect the validator set. It increases the decentralization and favors community governance.

PulseChain inherits and modifies the Binance Smart Chain consensus engine, Parlia, which combines DPoS and PoA. The PulseChain consensus engine has the following properties:

1. Blocks are produced by a limited set of validators.
2. Validators take turns to produce blocks in a PoA manner, similar to Ethereum's Clique consensus engine.
3. Validator set are elected in and out based on a staking contracts implemented on PulseChain.
4. Validator set rotation occurs on a regular interval with applicable validators chosen from the staking contract (selecting the validators with the bonded stake)
5. The consensus engine will interact directly with the slash, staking, and validator system-contracts to achieve liveness and stability, revenue distribution, and validator rotation.

Native Token

The native ETH token will become PLS on the PulseChain network. The PLS supply will be inflated by at least 10,000x upon forking, with the extra supply being distributed to the users that sacrificed during the PulseChain sacrifice phase.

PLS will be used just as ETH is used on the Ethereum network for transaction fees, as well as for delegating stake to network validators.

Building the source

Many of the below are the same as or similar to go-ethereum.

For prerequisites and detailed build instructions please read the Installation Instructions on the wiki.

Building geth requires both a Go (version 1.13 or later) and a C compiler. You can install them using your favourite package manager. Once the dependencies are installed, run

make geth

or, to build the full suite of utilities:

make all

Executables

The PulseChain project comes with several wrappers/executables found in the cmd directory.

Command	Description
geth	Main PulseChain client binary. It is the entry point into the Pulse network (main-, test- or private net), capable of running as a full node (default), archive node (retaining all historical state) or a light node (retrieving data live). It has the same and more RPC and other interface as go-ethereum and can be used by other processes as a gateway into the BSC network via JSON RPC endpoints exposed on top of HTTP, WebSocket and/or IPC transports. geth --help and the CLI Wiki page for command line options.
abigen	Source code generator to convert Ethereum contract definitions into easy to use, compile-time type-safe Go packages. It operates on plain Ethereum contract ABIs with expanded functionality if the contract bytecode is also available. However, it also accepts Solidity source files, making development much more streamlined. Please see our Native DApps wiki page for details.
bootnode	Stripped down version of our Ethereum client implementation that only takes part in the network node discovery protocol, but does not run any of the higher level application protocols. It can be used as a lightweight bootstrap node to aid in finding peers in private networks.
evm	Developer utility version of the EVM (Ethereum Virtual Machine) that is capable of running bytecode snippets within a configurable environment and execution mode. Its purpose is to allow isolated, fine-grained debugging of EVM opcodes (e.g. evm --code 60ff60ff --debug run).
gethrpctest	Developer utility tool to support our ethereum/rpc-test test suite which validates baseline conformity to the Ethereum JSON RPC specs. Please see the test suite's readme for details.
rlpdump	Developer utility tool to convert binary RLP (Recursive Length Prefix) dumps (data encoding used by the Ethereum protocol both network as well as consensus wise) to user-friendlier hierarchical representation (e.g. rlpdump --hex CE0183FFFFFFC4C304050583616263).
puppeth	a CLI wizard that aids in creating a new Ethereum network.

Running geth

Going through all the possible command line flags is out of scope here (please consult our CLI Wiki page).

Hardware Requirements

The hardware must meet certain requirements to run a full node.

• VPS running recent versions of Mac OS X or Linux.
• 500 GB of free disk space
• 8 cores of CPU and 16 gigabytes of memory (RAM) for mainnet.
• 4 cores of CPU and 8 gigabytes of memory (RAM) for testnet.
• A broadband Internet connection with upload/download speeds of at least 1 megabyte per second

A Full node on the PulseChain Testnet

TODO Provide instructions here once the PulseChain testnet is live.

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.

Programmatically interfacing geth nodes

As a developer, sooner rather than later you'll want to start interacting with geth and the PulseChain 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: 8545)
• --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 PulseChain nodes with exposed APIs! Further, all browser tabs can access locally running web servers, so malicious web pages could try to subvert locally available APIs!

License

The PulseChain Node 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 PulseChain Node 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.

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 AND B in second position
	// {{A}, {B}}         matches topic A in first position AND B in second position
	// {{A, B}, {C, D}}   matches topic (A OR B) in first position AND (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.