ipld-eth-beacon-indexer/pkg/beaconclient/capturehead.go

// This file will call all the functions to start and stop capturing the head of the beacon chain.

package beaconclient

import (
	"time"

	"github.com/ferranbt/fastssz/spectests"
	log "github.com/sirupsen/logrus"
	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
)

// This function will perform all the heavy lifting for tracking the head of the chain.
func (bc *BeaconClient) CaptureHead() {
	log.Info("We are tracking the head of the chain.")
	//bc.tempHelper()
	go bc.handleHead()
	go bc.handleFinalizedCheckpoint()
	go bc.handleReorgs()
	bc.captureEventTopic()
}

// A temporary helper function to see the output of beacon block and states.
func (bc *BeaconClient) tempHelper() {
	slot := "3200"
	blockEndpoint := bc.ServerEndpoint + bcBlockQueryEndpoint + slot
	stateEndpoint := bc.ServerEndpoint + bcStateQueryEndpoint + slot
	// Query
	log.Info("Get")
	blockSsz, _ := querySsz(blockEndpoint, slot)
	stateSsz, _ := querySsz(stateEndpoint, slot)
	// Transform
	log.Info("Tranform")
	stateObj := new(spectests.BeaconState)
	err := stateObj.UnmarshalSSZ(stateSsz)
	if err != nil {
		loghelper.LogSlotError(slot, err).Error("Unable to unmarshal the SSZ response from the Beacon Node Successfully!")
	}

	blockObj := new(spectests.SignedBeaconBlock)
	err = blockObj.UnmarshalSSZ(blockSsz)
	if err != nil {
		loghelper.LogSlotError(slot, err).Error("Unable to unmarshal the SSZ response from the Beacon Node Successfully!")
	}

	// Check
	log.Info("Check")
	log.Info("State Slot: ", stateObj.Slot)
	log.Info("Block Slot: ", blockObj.Block.Slot)
}

// Stop the head tracking service.
func (bc *BeaconClient) StopHeadTracking() error {
	log.Info("We are going to stop tracking the head of chain because of the shutdown signal.")
	chHead := make(chan bool)
	chReorg := make(chan bool)
	chFinal := make(chan bool)

	go bc.HeadTracking.finishProcessingChannel(chHead)
	go bc.ReOrgTracking.finishProcessingChannel(chReorg)
	go bc.FinalizationTracking.finishProcessingChannel(chFinal)

	<-chHead
	<-chFinal
	<-chReorg
	log.Info("Successfully stopped the head tracking service.")
	return nil
}

// This function closes the SSE subscription, but waits until the MessagesCh is empty
func (se *SseEvents[ProcessedEvents]) finishProcessingChannel(finish chan<- bool) {
	loghelper.LogEndpoint(se.Endpoint).Info("Received a close event.")
	se.SseClient.Unsubscribe(se.MessagesCh)
	for len(se.MessagesCh) != 0 || len(se.ProcessCh) != 0 {
		time.Sleep(time.Duration(shutdownWaitInterval) * time.Millisecond)
	}
	loghelper.LogEndpoint(se.Endpoint).Info("Done processing all messages, ready for shutdown")
	finish <- true
}