ipld-eth-beacon-indexer/internal/boot/boot.go

package boot

import (
	"fmt"
	"net/http"
	"strconv"

	log "github.com/sirupsen/logrus"
	"github.com/vulcanize/ipld-ethcl-indexer/pkg/database/sql/postgres"
	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
)

var (
	bcHealthEndpoint = "/eth/v1/node/health"
)

// This function will ensure that we can connect to the beacon client.
// Keep in mind, the beacon client will allow you to connect to it but it might
// Not allow you to make http requests. This is part of its built in logic, and you will have
// to follow their provided guidelines. https://lighthouse-book.sigmaprime.io/api-bn.html#security
func checkBeaconClient(bcAddress string, bcPort int) error {
	log.Debug("Attempting to connect to the beacon client")
	bcEndpoint := "http://" + bcAddress + ":" + strconv.Itoa(bcPort) + bcHealthEndpoint
	resp, err := http.Get(bcEndpoint)
	if err != nil {
		loghelper.LogError(err).Error("Unable to get bc endpoint: ", bcEndpoint)
		return err
	}

	if resp.StatusCode < 200 || resp.StatusCode > 299 {
		log.Error("We recieved a non 2xx status code when checking the health of the beacon node.")
		log.Error("Health Endpoint Status Code: ", resp.StatusCode)
		return fmt.Errorf("beacon Node Provided a non 2xx status code, code provided: %d", resp.StatusCode)
	}

	log.Info("We can successfully reach the beacon client.")
	return nil

}

// A simple wrapper to create a DB object to use.
func SetupDb(dbHostname string, dbPort int, dbName string, dbUsername string, dbPassword string, driverName string) (*postgres.DB, error) {
	log.Debug("Resolving Driver Type")
	DbDriver, err := postgres.ResolveDriverType(driverName)
	if err != nil {
		log.WithFields(log.Fields{
			"err":                  err,
			"driver_name_provided": driverName,
		}).Error("Can't resolve driver type")
	}
	log.Info("Using Driver:", DbDriver)

	postgresConfig := postgres.Config{
		Hostname:     dbHostname,
		Port:         dbPort,
		DatabaseName: dbName,
		Username:     dbUsername,
		Password:     dbPassword,
		Driver:       DbDriver,
	}
	DB, err := postgres.NewPostgresDB(postgresConfig)

	if err != nil {
		loghelper.LogError(err).Error("Unable to connect to the DB")
		return nil, err
	}
	return DB, err

}

// This function will perform some boot operations. If any steps fail, the application will fail to start.
// Keep in mind that the DB connection can be lost later in the lifecycle of the application or
// it might not be able to connect to the beacon client.
//
// 1. Make sure the Beacon client is up.
//
// 2. Connect to the database.
//
func BootApplication(dbHostname string, dbPort int, dbName string, dbUsername string, dbPassword string, driverName string, bcAddress string, bcPort int) (*postgres.DB, error) {
	log.Debug("Checking beacon Client")
	err := checkBeaconClient(bcAddress, bcPort)
	if err != nil {
		return nil, err
	}

	log.Debug("Setting up DB connection")
	DB, err := SetupDb(dbHostname, dbPort, dbName, dbUsername, dbPassword, driverName)
	if err != nil {
		return nil, err
	}
	return DB, nil
}