blockwatch

Documentation

Index

• type Client
• type Config
• type Event
• type EventType
• type GetBlockByNumberResponse
• type RpcClient
  • func NewRpcClient(rpcURL string, requestTimeout time.Duration) (*RpcClient, error)
  • func (rc *RpcClient) FilterLogs(q ethereum.FilterQuery) ([]types.Log, error)
  • func (rc *RpcClient) HeaderByHash(hash common.Hash) (*meshdb.MiniHeader, error)
  • func (rc *RpcClient) HeaderByNumber(number *big.Int) (*meshdb.MiniHeader, error)
• type Stack
  • func NewStack(meshDB *meshdb.MeshDB, limit int) *Stack
  • func (s *Stack) Inspect() ([]*meshdb.MiniHeader, error)
  • func (s *Stack) Peek() (*meshdb.MiniHeader, error)
  • func (s *Stack) Pop() (*meshdb.MiniHeader, error)
  • func (s *Stack) Push(block *meshdb.MiniHeader) error
• type Watcher
  • func New(config Config) *Watcher
  • func (w *Watcher) InspectRetainedBlocks() ([]*meshdb.MiniHeader, error)
  • func (w *Watcher) Start() error
  • func (w *Watcher) Stop()
  • func (w *Watcher) Subscribe(sink chan<- []*Event) event.Subscription

Types

type Client

type Client interface {
	HeaderByNumber(number *big.Int) (*meshdb.MiniHeader, error)
	HeaderByHash(hash common.Hash) (*meshdb.MiniHeader, error)
	FilterLogs(q ethereum.FilterQuery) ([]types.Log, error)
}

Client defines the methods needed to satisfy the client expected when instantiating a Watcher instance.

type Config

type Config struct {
	MeshDB              *meshdb.MeshDB
	PollingInterval     time.Duration
	StartBlockDepth     rpc.BlockNumber
	BlockRetentionLimit int
	WithLogs            bool
	Topics              []common.Hash
	Client              Client
}

Config holds some configuration options for an instance of BlockWatcher.

type Event

type Event struct {
	Type        EventType
	BlockHeader *meshdb.MiniHeader
}

Event describes a block event emitted by a Watcher

type EventType

type EventType int

EventType describes the types of events emitted by blockwatch.Watcher. A block can be discovered and added to our representation of the chain. During a block re-org, a block previously stored can be removed from the list.

const (
	Added EventType = iota
	Removed
)

type GetBlockByNumberResponse

type GetBlockByNumberResponse struct {
	Hash       common.Hash `json:"hash"`
	ParentHash common.Hash `json:"parentHash"`
	Number     string      `json:"number"`
}

type RpcClient

type RpcClient struct {
	// contains filtered or unexported fields
}

RpcClient is a Client for fetching Ethereum blocks from a specific JSON-RPC endpoint.

func NewRpcClient

func NewRpcClient(rpcURL string, requestTimeout time.Duration) (*RpcClient, error)

NewRpcClient returns a new Client for fetching Ethereum blocks using the given ethclient.Client.

func (*RpcClient) FilterLogs

func (rc *RpcClient) FilterLogs(q ethereum.FilterQuery) ([]types.Log, error)

FilterLogs returns the logs that satisfy the supplied filter query.

func (*RpcClient) HeaderByHash

func (rc *RpcClient) HeaderByHash(hash common.Hash) (*meshdb.MiniHeader, error)

HeaderByHash fetches a block header by its block hash. If no block exists with this number it will return a `ethereum.NotFound` error.

func (*RpcClient) HeaderByNumber

func (rc *RpcClient) HeaderByNumber(number *big.Int) (*meshdb.MiniHeader, error)

HeaderByNumber fetches a block header by its number. If no `number` is supplied, it will return the latest block header. If no block exists with this number it will return a `ethereum.NotFound` error.

type Stack

type Stack struct {
	// contains filtered or unexported fields
}

Stack allows performing basic stack operations on a stack of meshdb.MiniHeaders.

func NewStack

func NewStack(meshDB *meshdb.MeshDB, limit int) *Stack

NewStack instantiates a new stack with the specified size limit. Once the size limit is reached, adding additional blocks will evict the deepest block.

func (*Stack) Inspect

func (s *Stack) Inspect() ([]*meshdb.MiniHeader, error)

Inspect returns all the block headers currently on the stack

func (*Stack) Peek

func (s *Stack) Peek() (*meshdb.MiniHeader, error)

Peek returns the latest block header from the block stack without removing it. It returns nil if the stack is empty.

func (*Stack) Pop

func (s *Stack) Pop() (*meshdb.MiniHeader, error)

Pop removes and returns the latest block header on the block stack. It returns nil if the stack is empty.

func (*Stack) Push

func (s *Stack) Push(block *meshdb.MiniHeader) error

Push pushes a block header onto the block stack. If the stack limit is reached, it will remove the oldest block header.

type Watcher

type Watcher struct {
	Errors chan error
	// contains filtered or unexported fields
}

Watcher maintains a consistent representation of the latest `blockRetentionLimit` blocks, handling block re-orgs and network disruptions gracefully. It can be started from any arbitrary block height, and will emit both block added and removed events.

func New

func New(config Config) *Watcher

New creates a new Watcher instance.

func (*Watcher) InspectRetainedBlocks

func (w *Watcher) InspectRetainedBlocks() ([]*meshdb.MiniHeader, error)

InspectRetainedBlocks returns the blocks retained in-memory by the Watcher instance. It is not particularly performant and therefore should only be used for debugging and testing purposes.

func (*Watcher) Start

func (w *Watcher) Start() error

Start starts the BlockWatcher

func (*Watcher) Stop

func (w *Watcher) Stop()

Stop stops the BlockWatcher

func (*Watcher) Subscribe

func (w *Watcher) Subscribe(sink chan<- []*Event) event.Subscription

Subscribe allows one to subscribe to the block events emitted by the Watcher. To unsubscribe, simply call `Unsubscribe` on the returned subscription. The sink channel should have ample buffer space to avoid blocking other subscribers. Slow subscribers are not dropped.