Beacon

beacon is a Go package that can be used to interact with an Ethereum Beacon Node. It provides functions for interacting with a beacon node, and fetches/caches some data from the beacon node to make it easier to use.

As a general rule, any function that starts with Fetch will fetch data from the beacon node and cache it. All other functions will use the cached data.

Features

• Configurable health checks
• Concrete event callback registration
• Fetching/caching of some data from the beacon (like genesis and spec)

Built with

• attestantio/go-eth2-client
• ethpandaops/ethwallclock

Options

Check out the default options in options.go

Installation

go get github.com/ethpandaops/beacon

Usage

Simple example

package main

import (
  "context"
  "fmt"
  "log"

  "github.com/ethpandaops/beacon/pkg/beacon"
)

func main() {
  // Create options
  opts := *beacon.DefaultOptions()

  // Create beacon node instance
  beaconNode := beacon.NewNode(e.log, &beacon.Config{
    Addr: "localhost:5052",
    Name: "beacon node",
  }, "eth", opts)

  // Start the beacon node. Start will wait until the beacon node is ready.
  if err := beaconNode.Start(context.Background()); err != nil {
    log.Fatal(err)
  }

  block, err := beaconNode.FetchBlock(context.Background(), "head")
  if err != nil {
    log.Fatal(err)
  }

  fmt.Println(block)
}

Async ready example

package main

import (
  "context"
  "fmt"
  "log"

  "github.com/ethpandaops/beacon/pkg/beacon"
)

func main() {
  // Create options
  opts := *beacon.DefaultOptions()

  // Create beacon node instance
  beaconNode := beacon.NewNode(e.log, &beacon.Config{
    Addr: "localhost:5052",
    Name: "beacon node",
  }, "eth", opts)

  // Register a callback that will be called when the beacon node is ready.
  beaconNode.OnReady(func(ctx context.Context, event *ReadyEvent) error {
    block, err := beaconNode.FetchBlock(context.Background(), "head")
    if err != nil {
      return err
    }

    fmt.Println(block)

    return nil
  })

  // Start the beacon node. StartAsync will start the beacon node in the background.
  if err := beaconNode.StartAsync(context.Background()); err != nil {
    log.Fatal(err)
  }
}

Beacon Events

package main

import (
  "context"
  "fmt"
  "log"

  "github.com/ethpandaops/beacon/pkg/beacon"
)

func main() {
  // Create options
  opts := *beacon.DefaultOptions()

  // Create beacon node instance
  beaconNode := beacon.NewNode(e.log, &beacon.Config{
    Addr: "localhost:5052",
    Name: "beacon node",
  }, "eth", opts)

  // Register a callback that will be called when the beacon node is ready.
  beaconNode.OnBlock(func(ctx context.Context, event *v1.BlockEvent) error {
    fmt.Println(block)

    return nil
  })

  // Start the beacon node. StartAsync will start the beacon node in the background.
  if err := beaconNode.StartAsync(context.Background()); err != nil {
    log.Fatal(err)
  }
}