.github/workflows/on-pr.yml

@@ -14,10 +14,11 @@ on:
   pull_request:
     paths:
       - "!**.md"
-      - ".gitignore"
+      - "!.gitignore"
       - "!LICENSE"
       - "!.github/workflows/**"
       - ".github/workflows/on-pr.yml"
+      - "**"
 
 jobs:
   build:
@@ -33,8 +34,8 @@ jobs:
     runs-on: ubuntu-latest
     ## IF you want to update the default branch for `pull_request runs, do it after the ||`
     env:
-      foundry-test-ref: ${{ github.event.inputs.foundry-test-ref  || 'feature/build-stack'}}
+      foundry-test-ref: ${{ github.event.inputs.foundry-test-ref  || 'c17752de64f208f286f02379b80d2a935237c860'}}
-      ipld-eth-db-ref: ${{ github.event.inputs.ipld-eth-db-ref  || 'main' }}
+      ipld-eth-db-ref: ${{ github.event.inputs.ipld-eth-db-ref  || '05600e51d2163e1c5e2a872cb54606bc0a380d12' }}
       GOPATH: /tmp/go
     steps:
       - name: Create GOPATH

.gitignore

@@ -1,3 +1,5 @@
 
 ipld-ethcl-indexer
 ipld-ethcl-indexer.log
+report.json
+cover.profile

Makefile

@@ -30,6 +30,26 @@ integration-test-ci:
 	--cover --coverprofile=cover.profile \
 	--race --trace --json-report=report.json
 
+.PHONY: integration-test-local
+integration-test-local:
+	go vet ./...
+	go fmt ./...
+	$(GINKGO) -r --label-filter integration \
+	--procs=4 --compilers=4 \
+	--randomize-all --randomize-suites \
+	--fail-on-pending --keep-going \
+	--race --trace
+
+.PHONY: unit-test-local
+unit-test-local:
+	go vet ./...
+	go fmt ./...
+	$(GINKGO) -r --label-filter unit \
+	--procs=4 --compilers=4 \
+	--randomize-all --randomize-suites \
+	--fail-on-pending --keep-going \
+	--race --trace
+
 .PHONY: unit-test-ci
 unit-test-ci:
 	go vet ./...

application_component.md

@@ -10,6 +10,18 @@ This document will go through various application components
 
 # Components
 
-## Boot
+## `internal/boot`
 
 The boot package in `internal` is utilized to start the application. Everything in the boot process must complete successfully for the application to start. If it does not, the application will not start.
+
+## `pkg/database`
+
+The `database` package allows us to interact with a postgres DB. We utilize the interface to ensure we can interact with any `sql` database as well. I copied most of the code here from `vulcanize/go-ethereum`. Down the road, internal teams should be able to reference the package instead of copy pasting it and re-implementing it.
+
+## `pkg/beaconclient`
+
+This package will contain code to interact with the beacon client.
+
+## `pkg/version`
+
+A generic package which can be utilized to easily version our applications.

cmd/capture.go

@@ -6,20 +6,23 @@ package cmd
 
 import (
 	"os"
+	"time"
 
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 )
 
 var (
-	dbUsername string
+	dbUsername             string
-	dbPassword string
+	dbPassword             string
-	dbName     string
+	dbName                 string
-	dbAddress  string
+	dbAddress              string
-	dbDriver   string
+	dbDriver               string
-	dbPort     int
+	dbPort                 int
-	bcAddress  string
+	bcAddress              string
-	bcPort     int
+	bcPort                 int
+	bcConnectionProtocol   string
+	maxWaitSecondsShutdown time.Duration = time.Duration(5) * time.Second
 )
 
 // captureCmd represents the capture command
@@ -60,6 +63,7 @@ func init() {
 	//// Beacon Client Specific
 	captureCmd.PersistentFlags().StringVarP(&bcAddress, "bc.address", "l", "", "Address to connect to beacon node (required if username is set)")
 	captureCmd.PersistentFlags().IntVarP(&bcPort, "bc.port", "r", 0, "Port to connect to beacon node (required if username is set)")
+	captureCmd.PersistentFlags().StringVarP(&bcConnectionProtocol, "bc.connectionProtocol", "", "http", "protocol for connecting to the beacon node.")
 	err = captureCmd.MarkPersistentFlagRequired("bc.address")
 	exitErr(err)
 	err = captureCmd.MarkPersistentFlagRequired("bc.port")
@@ -85,6 +89,8 @@ func init() {
 	exitErr(err)
 	err = viper.BindPFlag("bc.port", captureCmd.PersistentFlags().Lookup("bc.port"))
 	exitErr(err)
+	err = viper.BindPFlag("bc.connectionProtocol", captureCmd.PersistentFlags().Lookup("bc.connectionProtocol"))
+	exitErr(err)
 	// Here you will define your flags and configuration settings.
 
 }

cmd/head.go

@@ -5,8 +5,13 @@ Copyright © 2022 NAME HERE <EMAIL ADDRESS>
 package cmd
 
 import (
+	"context"
+	"time"
+
+	log "github.com/sirupsen/logrus"
 	"github.com/spf13/cobra"
 	"github.com/vulcanize/ipld-ethcl-indexer/internal/boot"
+	"github.com/vulcanize/ipld-ethcl-indexer/internal/shutdown"
 	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
 )
 
@@ -22,10 +27,20 @@ var headCmd = &cobra.Command{
 
 // Start the application to track at head.
 func startHeadTracking() {
-	_, err := boot.BootApplicationWithRetry(dbAddress, dbPort, dbName, dbUsername, dbPassword, dbDriver, bcAddress, bcPort)
+	// Boot the application
+	log.Info("Starting the application in head tracking mode.")
+	ctx := context.Background()
+
+	BC, DB, err := boot.BootApplicationWithRetry(ctx, dbAddress, dbPort, dbName, dbUsername, dbPassword, dbDriver, bcAddress, bcPort, bcConnectionProtocol)
 	if err != nil {
 		loghelper.LogError(err).Error("Unable to Start application")
 	}
+
+	// Capture head blocks
+	go BC.CaptureHead()
+
+	// Shutdown when the time is right.
+	shutdown.ShutdownServices(ctx, time.Duration(maxWaitSecondsShutdown), DB, BC)
 }
 
 func init() {

go.mod

@@ -19,13 +19,16 @@ require (
 	github.com/jackc/puddle v1.2.1 // indirect
 	github.com/kr/text v0.2.0 // indirect
 	github.com/lib/pq v1.10.4 // indirect
+	github.com/minio/sha256-simd v0.1.1 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	golang.org/x/crypto v0.0.0-20220411220226-7b82a4e95df4 // indirect
 	golang.org/x/net v0.0.0-20220412020605-290c469a71a5 // indirect
+	gopkg.in/cenkalti/backoff.v1 v1.1.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 )
 
 require (
+	github.com/ferranbt/fastssz v0.0.0-20220303160658-88bb965b6747
 	github.com/fsnotify/fsnotify v1.5.1 // indirect
 	github.com/georgysavva/scany v0.3.0
 	github.com/hashicorp/hcl v1.0.0 // indirect
@@ -35,6 +38,7 @@ require (
 	github.com/mitchellh/mapstructure v1.4.3 // indirect
 	github.com/pelletier/go-toml v1.9.4 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.0-beta.8 // indirect
+	github.com/r3labs/sse v0.0.0-20210224172625-26fe804710bc
 	github.com/spf13/afero v1.8.2 // indirect
 	github.com/spf13/cast v1.4.1 // indirect
 	github.com/spf13/cobra v1.4.0

go.sum

@@ -65,6 +65,8 @@ github.com/envoyproxy/go-control-plane v0.9.4/go.mod h1:6rpuAdCZL397s3pYoYcLgu1m
 github.com/envoyproxy/go-control-plane v0.9.7/go.mod h1:cwu0lG7PUMfa9snN8LXBig5ynNVH9qI8YYLbd1fK2po=
 github.com/envoyproxy/go-control-plane v0.9.9-0.20201210154907-fd9021fe5dad/go.mod h1:cXg6YxExXjJnVBQHBLXeUAgxn2UodCpnH306RInaBQk=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
+github.com/ferranbt/fastssz v0.0.0-20220303160658-88bb965b6747 h1:K2Bt7NSX8x/5MD2RiO7cPLy21dBgnQ84r9uR0QYoHrE=
+github.com/ferranbt/fastssz v0.0.0-20220303160658-88bb965b6747/go.mod h1:S8yiDeAXy8f88W4Ul+0dBMPx49S05byYbmZD6Uv94K4=
 github.com/fsnotify/fsnotify v1.4.7/go.mod h1:jwhsz4b93w/PPRr/qN1Yymfu8t87LnFCMoQvtojpjFo=
 github.com/fsnotify/fsnotify v1.4.9/go.mod h1:znqG4EE+3YCdAaPaxE2ZRY/06pZUdp0tY4IgpuI1SZQ=
 github.com/fsnotify/fsnotify v1.5.1 h1:mZcQUHVQUQWoPXXtuf9yuEXKudkV2sx1E06UadKWpgI=
@@ -112,6 +114,8 @@ github.com/golang/protobuf v1.4.3/go.mod h1:oDoupMAO8OvCJWAcko0GGGIgR6R6ocIYbsSw
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
 github.com/golang/protobuf v1.5.2 h1:ROPKBNFfQgOUMifHyP+KYbvpjbdoFNs+aK7DXlji0Tw=
 github.com/golang/protobuf v1.5.2/go.mod h1:XVQd3VNwM+JqD3oG2Ue2ip4fOMUkwXdXDdiuN0vRsmY=
+github.com/golang/snappy v0.0.3 h1:fHPg5GQYlCeLIPB9BZqMVR5nR9A+IM5zcgeTdjMYmLA=
+github.com/golang/snappy v0.0.3/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/google/btree v0.0.0-20180813153112-4030bb1f1f0c/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/btree v1.0.0/go.mod h1:lNA+9X1NB3Zf8V7Ke586lFgjr2dZNuvo3lPJSGZ5JPQ=
 github.com/google/go-cmp v0.2.0/go.mod h1:oXzfMopK8JAjlY9xF4vHSVASa0yLyX7SntLO5aqRK0M=
@@ -251,6 +255,9 @@ github.com/mattn/go-isatty v0.0.8/go.mod h1:Iq45c/XA43vh69/j3iqttzPXn0bhXyGjM0Hd
 github.com/mattn/go-isatty v0.0.9/go.mod h1:YNRxwqDuOph6SZLI9vUUz6OYw3QyUt7WiY2yME+cCiQ=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
 github.com/mattn/go-sqlite3 v1.14.6/go.mod h1:NyWgC/yNuGj7Q9rpYnZvas74GogHl5/Z4A/KQRfk6bU=
+github.com/minio/sha256-simd v0.1.1 h1:5QHSlgo3nt5yKOJrC7W8w7X+NFl8cMPZm96iu8kKUJU=
+github.com/minio/sha256-simd v0.1.1/go.mod h1:B5e1o+1/KgNmWrSQK08Y6Z1Vb5pwIktudl0J58iy0KM=
+github.com/mitchellh/mapstructure v1.3.2/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/mitchellh/mapstructure v1.4.3 h1:OVowDSCllw/YjdLkam3/sm7wEtOy59d8ndGgCcyj8cs=
 github.com/mitchellh/mapstructure v1.4.3/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
 github.com/nxadm/tail v1.4.4/go.mod h1:kenIhsEOeOJmVchQTgglprH7qJGnHDVpk1VPCcaMI8A=
@@ -276,6 +283,8 @@ github.com/pkg/sftp v1.13.1/go.mod h1:3HaPG6Dq1ILlpPZRO0HVMrsydcdLt6HRDccSgb87qR
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
+github.com/r3labs/sse v0.0.0-20210224172625-26fe804710bc h1:zAsgcP8MhzAbhMnB1QQ2O7ZhWYVGYSR2iVcjzQuPV+o=
+github.com/r3labs/sse v0.0.0-20210224172625-26fe804710bc/go.mod h1:S8xSOnV3CgpNrWd0GQ/OoQfMtlg2uPRSuTzcSGrzwK8=
 github.com/rogpeppe/go-internal v1.3.0/go.mod h1:M8bDsm7K2OlrFYOpmOWEs/qY81heoFRclV5y23lUDJ4=
 github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
 github.com/rs/zerolog v1.13.0/go.mod h1:YbFCdg8HfsridGWAh22vktObvhZbQsZXe4/zB0OKkWU=
@@ -401,6 +410,7 @@ golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLL
 golang.org/x/net v0.0.0-20190628185345-da137c7871d7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190724013045-ca1201d0de80/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20190813141303-74dc4d7220e7/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20191116160921-f9c825593386/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20191209160850-c0dbc17a3553/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20200202094626-16171245cfb2/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
@@ -660,6 +670,8 @@ google.golang.org/protobuf v1.25.0/go.mod h1:9JNX74DMeImyA3h4bdi1ymwjUzf21/xIlba
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.26.0/go.mod h1:9q0QmTI4eRPtz6boOQmLYwt+qCgq0jsYwAQnmE0givc=
 google.golang.org/protobuf v1.28.0 h1:w43yiav+6bVFTBQFZX0r7ipe9JQ1QsbMgHwbBziscLw=
+gopkg.in/cenkalti/backoff.v1 v1.1.0 h1:Arh75ttbsvlpVA7WtVpH4u9h6Zl46xuptxqLxPiSo4Y=
+gopkg.in/cenkalti/backoff.v1 v1.1.0/go.mod h1:J6Vskwqd+OMVJl8C33mmtxTBs2gyzfv7UDAkHu8BrjI=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=

internal/boot/boot.go

@@ -1,48 +1,23 @@
 package boot
 
 import (
-	"fmt"
+	"context"
-	"net/http"
-	"strconv"
 	"time"
 
 	log "github.com/sirupsen/logrus"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/beaconclient"
 	"github.com/vulcanize/ipld-ethcl-indexer/pkg/database/sql"
 	"github.com/vulcanize/ipld-ethcl-indexer/pkg/database/sql/postgres"
 	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
 )
 
 var (
-	bcHealthEndpoint              = "/eth/v1/node/health"
+	maxRetry                                 = 5  // Max times to try to connect to the DB or BC at boot.
-	maxRetry                      = 5  // Max times to try to connect to the DB or BC at boot.
+	retryInterval                            = 30 // The time to wait between each try.
-	retryInterval                 = 30 // The time to wait between each try.
+	DB            sql.Database               = &postgres.DB{}
-	DB               sql.Database = &postgres.DB{}
+	BC            *beaconclient.BeaconClient = &beaconclient.BeaconClient{}
 )
 
-// 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 SetupPostgresDb(dbHostname string, dbPort int, dbName string, dbUsername string, dbPassword string, driverName string) (sql.Database, error) {
 	log.Debug("Resolving Driver Type")
@@ -81,35 +56,38 @@ func SetupPostgresDb(dbHostname string, dbPort int, dbName string, dbUsername st
 //
 // 2. Connect to the database.
 //
-func BootApplication(dbHostname string, dbPort int, dbName string, dbUsername string, dbPassword string, driverName string, bcAddress string, bcPort int) (sql.Database, error) {
+func BootApplication(ctx context.Context, dbHostname string, dbPort int, dbName string, dbUsername string, dbPassword string, driverName string, bcAddress string, bcPort int, bcConnectionProtocol string) (*beaconclient.BeaconClient, sql.Database, error) {
 	log.Info("Booting the Application")
 
-	log.Debug("Checking beacon Client")
+	log.Debug("Creating the Beacon Client")
-	err := checkBeaconClient(bcAddress, bcPort)
+	BC = beaconclient.CreateBeaconClient(ctx, bcConnectionProtocol, bcAddress, bcPort)
+
+	log.Debug("Checking Beacon Client")
+	err := BC.CheckBeaconClient()
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 
 	log.Debug("Setting up DB connection")
 	DB, err := SetupPostgresDb(dbHostname, dbPort, dbName, dbUsername, dbPassword, driverName)
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
-	return DB, nil
+	return BC, DB, nil
 }
 
 // Add retry logic to ensure that we are give the Beacon Client and the DB time to start.
-func BootApplicationWithRetry(dbHostname string, dbPort int, dbName string, dbUsername string, dbPassword string, driverName string, bcAddress string, bcPort int) (sql.Database, error) {
+func BootApplicationWithRetry(ctx context.Context, dbHostname string, dbPort int, dbName string, dbUsername string, dbPassword string, driverName string, bcAddress string, bcPort int, bcConnectionProtocol string) (*beaconclient.BeaconClient, sql.Database, error) {
 	var err error
 	for i := 0; i < maxRetry; i++ {
-		DB, err = BootApplication(dbHostname, dbPort, dbName, dbUsername, dbPassword, driverName, bcAddress, bcPort)
+		BC, DB, err = BootApplication(ctx, dbHostname, dbPort, dbName, dbUsername, dbPassword, driverName, bcAddress, bcPort, bcConnectionProtocol)
 		if err != nil {
 			log.WithFields(log.Fields{
 				"retryNumber": i,
 			}).Warn("Unable to boot application. Going to try again")
 			time.Sleep(time.Duration(retryInterval) * time.Second)
-			continue
 		}
+		break
 	}
-	return DB, err
+	return BC, DB, err
 }

internal/boot/boot_test.go

@@ -1,6 +1,8 @@
 package boot_test
 
 import (
+	"context"
+
 	. "github.com/onsi/ginkgo/v2"
 	. "github.com/onsi/gomega"
 	"github.com/vulcanize/ipld-ethcl-indexer/internal/boot"
@@ -8,38 +10,39 @@ import (
 
 var _ = Describe("Boot", func() {
 	var (
-		dbAddress  string = "localhost"
+		dbAddress            string = "localhost"
-		dbPort     int    = 8077
+		dbPort               int    = 8077
-		dbName     string = "vulcanize_testing"
+		dbName               string = "vulcanize_testing"
-		dbUsername string = "vdbm"
+		dbUsername           string = "vdbm"
-		dbPassword string = "password"
+		dbPassword           string = "password"
-		dbDriver   string = "PGX"
+		dbDriver             string = "PGX"
-		bcAddress  string = "localhost"
+		bcAddress            string = "localhost"
-		bcPort     int    = 5052
+		bcPort               int    = 5052
+		bcConnectionProtocol string = "http"
 	)
 	Describe("Booting the application", Label("integration"), func() {
 		Context("When the DB and BC are both up and running", func() {
 			It("Should connect successfully", func() {
-				db, err := boot.BootApplicationWithRetry(dbAddress, dbPort, dbName, dbUsername, dbPassword, dbDriver, bcAddress, bcPort)
+				_, db, err := boot.BootApplicationWithRetry(context.Background(), dbAddress, dbPort, dbName, dbUsername, dbPassword, dbDriver, bcAddress, bcPort, bcConnectionProtocol)
 				defer db.Close()
 				Expect(err).To(BeNil())
 			})
 		})
 		Context("When the DB is running but not the BC", func() {
 			It("Should not connect successfully", func() {
-				_, err := boot.BootApplication(dbAddress, dbPort, dbName, dbUsername, dbPassword, dbDriver, "hi", 100)
+				_, _, err := boot.BootApplication(context.Background(), dbAddress, dbPort, dbName, dbUsername, dbPassword, dbDriver, "hi", 100, bcConnectionProtocol)
 				Expect(err).ToNot(BeNil())
 			})
 		})
 		Context("When the BC is running but not the DB", func() {
 			It("Should not connect successfully", func() {
-				_, err := boot.BootApplication("hi", 10, dbName, dbUsername, dbPassword, dbDriver, bcAddress, bcPort)
+				_, _, err := boot.BootApplication(context.Background(), "hi", 10, dbName, dbUsername, dbPassword, dbDriver, bcAddress, bcPort, bcConnectionProtocol)
 				Expect(err).ToNot(BeNil())
 			})
 		})
 		Context("When neither the BC or DB are running", func() {
 			It("Should not connect successfully", func() {
-				_, err := boot.BootApplication("hi", 10, dbName, dbUsername, dbPassword, dbDriver, "hi", 100)
+				_, _, err := boot.BootApplication(context.Background(), "hi", 10, dbName, dbUsername, dbPassword, dbDriver, "hi", 100, bcConnectionProtocol)
 				Expect(err).ToNot(BeNil())
 			})
 		})

internal/shutdown/shutdown.go

@@ -0,0 +1,39 @@
+package shutdown
+
+import (
+	"context"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/beaconclient"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/database/sql"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/gracefulshutdown"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
+)
+
+// Shutdown all the internal services for the application.
+func ShutdownServices(ctx context.Context, waitTime time.Duration, DB sql.Database, BC *beaconclient.BeaconClient) {
+	successCh, errCh := gracefulshutdown.Shutdown(ctx, waitTime, map[string]gracefulshutdown.Operation{
+		"database": func(ctx context.Context) error {
+			err := DB.Close()
+			if err != nil {
+				loghelper.LogError(err).Error("Unable to close the DB")
+			}
+			return err
+		},
+		"beaconClient": func(ctx context.Context) error {
+			err := BC.StopHeadTracking()
+			if err != nil {
+				loghelper.LogError(err).Error("Unable to trigger shutdown of head tracking")
+			}
+			return err
+		},
+	})
+
+	select {
+	case _ = <-successCh:
+		log.Info("Gracefully Shutdown ipld-ethcl-indexer!")
+	case err := <-errCh:
+		loghelper.LogError(err).Error("Ungracefully Shutdown ipld-ethcl-indexer!")
+	}
+}

pkg/beaconclient/beaconclient.go

@@ -0,0 +1,73 @@
+package beaconclient
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/r3labs/sse"
+	log "github.com/sirupsen/logrus"
+)
+
+var (
+	bcHealthEndpoint         = "/eth/v1/node/health"                        // Endpoint used for the healthcheck
+	bcHeadTopicEndpoint      = "/eth/v1/events?topics=head"                 // Endpoint used to subscribe to the head of the chain
+	bcReorgTopicEndpoint     = "/eth/v1/events?topics=chain_reorg"          // Endpoint used to subscribe to the head of the chain
+	bcFinalizedTopicEndpoint = "/eth/v1/events?topics=finalized_checkpoint" // Endpoint used to subscribe to the head of the chain
+	bcBlockQueryEndpoint     = "/eth/v2/beacon/blocks/"                     // Endpoint to query individual Blocks
+	bcStateQueryEndpoint     = "/eth/v2/debug/beacon/states/"               // Endpoint to query individual States
+)
+
+// A struct that capture the Beacon Server that the Beacon Client will be interacting with and querying.
+type BeaconClient struct {
+	Context                     context.Context                 // A context generic context with multiple uses.
+	ServerEndpoint              string                          // What is the endpoint of the beacon server.
+	PerformHeadTracking         bool                            // Should we track head?
+	PerformHistoricalProcessing bool                            // Should we perform historical processing?
+	HeadTracking                *SseEvents[Head]                // Track the head block
+	ReOrgTracking               *SseEvents[ChainReorg]          // Track all Reorgs
+	FinalizationTracking        *SseEvents[FinalizedCheckpoint] // Track all finalization checkpoints
+}
+
+// A struct to keep track of relevant the head event topic.
+type SseEvents[P ProcessedEvents] struct {
+	Endpoint   string          // The endpoint for the subscription. Primarily used for logging
+	MessagesCh chan *sse.Event // Contains all the messages from the SSE Channel
+	ErrorCh    chan *SseError  // Contains any errors while SSE streaming occurred
+	ProcessCh  chan *P         // Used to capture processed data in its proper struct.
+	SseClient  *sse.Client     // sse.Client object that is used to interact with the SSE stream
+}
+
+// An object to capture any errors when turning an SSE message to JSON.
+type SseError struct {
+	err error
+	msg []byte
+}
+
+// A Function to create the BeaconClient.
+func CreateBeaconClient(ctx context.Context, connectionProtocol string, bcAddress string, bcPort int) *BeaconClient {
+	endpoint := fmt.Sprintf("%s://%s:%d", connectionProtocol, bcAddress, bcPort)
+	log.Info("Creating the BeaconClient")
+	return &BeaconClient{
+		Context:              ctx,
+		ServerEndpoint:       endpoint,
+		HeadTracking:         createSseEvent[Head](endpoint, bcHeadTopicEndpoint),
+		ReOrgTracking:        createSseEvent[ChainReorg](endpoint, bcReorgTopicEndpoint),
+		FinalizationTracking: createSseEvent[FinalizedCheckpoint](endpoint, bcFinalizedTopicEndpoint),
+	}
+}
+
+// Create all the channels to handle a SSE events
+func createSseEvent[P ProcessedEvents](baseEndpoint string, path string) *SseEvents[P] {
+	endpoint := baseEndpoint + path
+	sseEvents := &SseEvents[P]{
+		Endpoint:   endpoint,
+		MessagesCh: make(chan *sse.Event),
+		ErrorCh:    make(chan *SseError),
+		ProcessCh:  make(chan *P),
+		SseClient: func(endpoint string) *sse.Client {
+			log.WithFields(log.Fields{"endpoint": endpoint}).Info("Creating SSE client")
+			return sse.NewClient(endpoint)
+		}(endpoint),
+	}
+	return sseEvents
+}

pkg/beaconclient/beaconclient_suite_test.go

@@ -0,0 +1,13 @@
+package beaconclient_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestBeaconClient(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "BeaconClient Suite", Label("beacon-client"))
+}

pkg/beaconclient/capturehead.go

@@ -0,0 +1,79 @@
+// 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
+}

pkg/beaconclient/healthcheck.go

@@ -0,0 +1,33 @@
+package beaconclient
+
+import (
+	"fmt"
+	"net/http"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
+)
+
+// 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 (bc BeaconClient) CheckBeaconClient() error {
+	log.Debug("Attempting to connect to the beacon client")
+	bcEndpoint := bc.ServerEndpoint + 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
+
+}

pkg/beaconclient/healthcheck_test.go

@@ -0,0 +1,30 @@
+package beaconclient_test
+
+import (
+	"context"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+	beaconclient "github.com/vulcanize/ipld-ethcl-indexer/pkg/beaconclient"
+)
+
+var _ = Describe("Healthcheck", func() {
+	var (
+		BC    = beaconclient.CreateBeaconClient(context.Background(), "http", "localhost", 5052)
+		errBc = beaconclient.CreateBeaconClient(context.Background(), "http", "blah-blah", 1010)
+	)
+	Describe("Connecting to the lighthouse client", Label("integration"), func() {
+		Context("When the client is running", func() {
+			It("We should connect successfully", func() {
+				err := BC.CheckBeaconClient()
+				Expect(err).To(BeNil())
+			})
+		})
+		Context("When the client is not running", func() {
+			It("We not should connect successfully", func() {
+				err := errBc.CheckBeaconClient()
+				Expect(err).ToNot(BeNil())
+			})
+		})
+	})
+})

pkg/beaconclient/incomingsse.go

@@ -0,0 +1,66 @@
+// This package will handle all event subscriptions that utilize SSE.
+
+package beaconclient
+
+import (
+	"encoding/json"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
+)
+
+var (
+	shutdownWaitInterval = time.Duration(5) * time.Second
+)
+
+// This function will capture all the SSE events for a given SseEvents object.
+// When new messages come in, it will ensure that they are decoded into JSON.
+// If any errors occur, it log the error information.
+func handleIncomingSseEvent[P ProcessedEvents](eventHandler *SseEvents[P]) {
+	loghelper.LogEndpoint(eventHandler.Endpoint).Info("Subscribing to Messages")
+	go eventHandler.SseClient.SubscribeChanRaw(eventHandler.MessagesCh)
+	for {
+		select {
+		case message := <-eventHandler.MessagesCh:
+			// Message can be nil if its a keep-alive message
+			if len(message.Data) != 0 {
+				go processMsg(message.Data, eventHandler.ProcessCh, eventHandler.ErrorCh)
+			}
+
+		case headErr := <-eventHandler.ErrorCh:
+			log.WithFields(log.Fields{
+				"endpoint": eventHandler.Endpoint,
+				"err":      headErr.err,
+				"msg":      headErr.msg,
+			},
+			).Error("Unable to handle event.")
+
+		case process := <-eventHandler.ProcessCh:
+			log.WithFields(log.Fields{"processed": process}).Debug("Processesing a Message")
+		}
+	}
+}
+
+// Turn the data object into a Struct.
+func processMsg[P ProcessedEvents](msg []byte, processCh chan<- *P, errorCh chan<- *SseError) {
+	var msgMarshaled P
+	err := json.Unmarshal(msg, &msgMarshaled)
+	if err != nil {
+		loghelper.LogError(err).Error("Unable to parse message")
+		errorCh <- &SseError{
+			err: err,
+			msg: msg,
+		}
+		return
+	}
+	processCh <- &msgMarshaled
+}
+
+// Capture all of the event topics.
+func (bc *BeaconClient) captureEventTopic() {
+	log.Info("We are capturing all SSE events")
+	go handleIncomingSseEvent(bc.HeadTracking)
+	go handleIncomingSseEvent(bc.ReOrgTracking)
+	go handleIncomingSseEvent(bc.FinalizationTracking)
+}

pkg/beaconclient/models.go

@@ -0,0 +1,37 @@
+package beaconclient
+
+// This interface captured what the events can be for processed event streams.
+type ProcessedEvents interface {
+	Head | FinalizedCheckpoint | ChainReorg
+}
+
+// This struct captures the JSON representation of the head topic
+type Head struct {
+	Slot                      string `json:"slot"`
+	Block                     string `json:"block"`
+	State                     string `json:"state"`
+	CurrentDutyDependentRoot  string `json:"current_duty_dependent_root"`
+	PreviousDutyDependentRoot string `json:"previous_duty_dependent_root"`
+	EpochTransition           bool   `json:"epoch_transition"`
+	ExecutionOptimistic       bool   `json:"execution_optimistic"`
+}
+
+// This struct captures the JSON representation of the finalized_checkpoint topic.
+type FinalizedCheckpoint struct {
+	Block               string `json:"block"`
+	State               string `json:"state"`
+	Epoch               string `json:"epoch"`
+	ExecutionOptimistic bool   `json:"execution_optimistic"`
+}
+
+// This struct captures the JSON representation of the chain_reorg topic.
+type ChainReorg struct {
+	Slot                string `json:"slot"`
+	Depth               string `json:"depth"`
+	OldHeadBlock        string `json:"old_head_block"`
+	NewHeadBlock        string `json:"new_head_block"`
+	OldHeadState        string `json:"old_head_state"`
+	NewHeadState        string `json:"new_head_state"`
+	Epoch               string `json:"epoch"`
+	ExecutionOptimistic bool   `json:"execution_optimistic"`
+}

pkg/beaconclient/processevents.go

@@ -0,0 +1,38 @@
+// This file contains all the functions to handle SSE events after they have been turned
+// to the structs.
+
+package beaconclient
+
+import log "github.com/sirupsen/logrus"
+
+// This function will perform the necessary steps to handle a reorg.
+func (bc *BeaconClient) handleReorgs() {
+	log.Info("Starting to process reorgs.")
+	for {
+		// We will add real functionality later
+		reorg := <-bc.ReOrgTracking.ProcessCh
+		log.WithFields(log.Fields{"reorg": reorg}).Debug("Received a new reorg message.")
+	}
+}
+
+// This function will perform the necessary steps to handle a reorg.
+func (bc *BeaconClient) handleFinalizedCheckpoint() {
+	log.Info("Starting to process finalized checkpoints.")
+	for {
+		// We will add real functionality later
+		finalized := <-bc.ReOrgTracking.ProcessCh
+		log.WithFields(log.Fields{"finalized": finalized}).Debug("Received a new finalized checkpoint.")
+	}
+
+}
+
+// This function will handle the latest head event.
+func (bc *BeaconClient) handleHead() {
+	log.Info("Starting to process head.")
+	for {
+		// We will add real functionality later
+		head := <-bc.ReOrgTracking.ProcessCh
+		log.WithFields(log.Fields{"head": head}).Debug("Received a new head event.")
+	}
+
+}

pkg/beaconclient/queryserver.go

@@ -0,0 +1,101 @@
+// This file will contain functions to query the Beacon Chain Server.
+
+package beaconclient
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net/http"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
+)
+
+// Attempt to use generics..
+// // These are types that append slot at the end of the URL to handle a request.
+// type SlotBasedRequests interface {
+// 	*specs.BeaconState | *specs.SignedBeaconBlock
+// 	UnmarshalSSZ([]byte) error
+// }
+//
+// func queryState[R SlotBasedRequests](endpoint string, slot string) (R, error) {
+// 	obj := new(R)
+// 	rawState, err := querySlot(endpoint, slot)
+// 	if err != nil {
+// 		return *obj, err
+// 	}
+//
+// 	err = &obj.UnmarshalSSZ(rawState)
+// 	err = (*obj).UnmarshalSSZ(rawState)
+// 	if err != nil {
+// 		loghelper.LogSlotError(slot, err).Error("Unable to unmarshal the SSZ response from the Beacon Node Successfully!")
+// 		return *obj, fmt.Errorf("Unable to unmarshal the SSZ response from the Beacon Node Successfully!: %s", err.Error())
+// 	}
+// 	return *obj, nil
+// }
+
+// This function will query a state object based on the slot provided.
+// The object is SSZ encoded.
+
+//type BeaconBlockResponse struct {
+//	version string `json: `
+//}
+
+// func queryState(endpoint string, slot string) (spectests.BeaconState, error) {
+// 	obj := new(spectests.BeaconState)
+// 	fullEndpoint := endpoint + slot
+// 	rawState, err := querySsz(fullEndpoint, slot)
+// 	if err != nil {
+// 		return *obj, err
+// 	}
+//
+// 	err = obj.UnmarshalSSZ(rawState)
+// 	if err != nil {
+// 		loghelper.LogSlotError(slot, err).Error("Unable to unmarshal the SSZ response from the Beacon Node")
+// 		return *obj, fmt.Errorf("Unable to unmarshal the SSZ response from the Beacon Node: %s", err.Error())
+// 	}
+// 	return *obj, nil
+// }
+//
+// // This function will query a state object based on the slot provided.
+// // The object is SSZ encoded.
+// func queryBlock(endpoint string, slot string) (spectests.SignedBeaconBlock, error) {
+// 	obj := new(spectests.SignedBeaconBlock)
+// 	fullEndpoint := endpoint + slot
+// 	rawBlock, err := querySsz(fullEndpoint, slot)
+// 	if err != nil {
+// 		return *obj, err
+// 	}
+//
+// 	err = obj.UnmarshalSSZ(rawBlock)
+// 	if err != nil {
+// 		loghelper.LogSlotError(slot, err).Error("Unable to unmarshal the SSZ response from the Beacon Node Successfully!")
+// 		return *obj, fmt.Errorf("Unable to unmarshal the SSZ response from the Beacon Node Successfully!: %s", err.Error())
+// 	}
+// 	return *obj, nil
+// }
+
+// A helper function to query endpoints that utilize slots.
+func querySsz(endpoint string, slot string) ([]byte, error) {
+	log.WithFields(log.Fields{"endpoint": endpoint}).Info("Querying endpoint")
+	client := &http.Client{}
+	req, err := http.NewRequest("GET", endpoint, nil)
+	if err != nil {
+		loghelper.LogSlotError(slot, err).Error("Unable to create a request!")
+		return nil, fmt.Errorf("Unable to create a request!: %s", err.Error())
+	}
+	// Not set correctly
+	req.Header.Set("Accept", "application/octet-stream")
+	response, err := client.Do(req)
+	if err != nil {
+		loghelper.LogSlotError(slot, err).Error("Unable to query Beacon Node!")
+		return nil, fmt.Errorf("Unable to query Beacon Node: %s", err.Error())
+	}
+	defer response.Body.Close()
+	body, err := ioutil.ReadAll(response.Body)
+	if err != nil {
+		loghelper.LogSlotError(slot, err).Error("Unable to turn response into a []bytes array!")
+		return nil, fmt.Errorf("Unable to turn response into a []bytes array!: %s", err.Error())
+	}
+	return body, nil
+}

pkg/gracefulshutdown/gracefulshutdown.go

@@ -0,0 +1,67 @@
+package gracefulshutdown
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/signal"
+	"sync"
+	"syscall"
+	"time"
+
+	log "github.com/sirupsen/logrus"
+	"github.com/vulcanize/ipld-ethcl-indexer/pkg/loghelper"
+)
+
+// operation is a clean up function on shutting down
+type Operation func(ctx context.Context) error
+
+// gracefulShutdown waits for termination syscalls and doing clean up operations after received it
+func Shutdown(ctx context.Context, timeout time.Duration, ops map[string]Operation) (<-chan struct{}, <-chan error) {
+	waitCh := make(chan struct{})
+	errCh := make(chan error)
+	go func() {
+		s := make(chan os.Signal, 1)
+
+		// add any other syscalls that you want to be notified with
+		signal.Notify(s, syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
+		<-s
+
+		log.Info("Shutting Down your application")
+
+		// set timeout for the ops to be done to prevent system hang
+		timeoutFunc := time.AfterFunc(timeout, func() {
+			log.Warnf("timeout %d ms has been elapsed, force exit", timeout.Milliseconds())
+			errCh <- fmt.Errorf("Application shutdown took too long.")
+			return
+		})
+
+		defer timeoutFunc.Stop()
+
+		var wg sync.WaitGroup
+
+		// Do the operations asynchronously to save time
+		for key, op := range ops {
+			wg.Add(1)
+			innerOp := op
+			innerKey := key
+			go func() {
+				defer wg.Done()
+
+				log.Infof("cleaning up: %s", innerKey)
+				if err := innerOp(ctx); err != nil {
+					loghelper.LogError(err).Errorf("%s: clean up failed: %s", innerKey, err.Error())
+					return
+				}
+
+				log.Infof("%s was shutdown gracefully", innerKey)
+			}()
+		}
+
+		wg.Wait()
+
+		close(waitCh)
+	}()
+
+	return waitCh, errCh
+}

pkg/loghelper/log_endpoint.go

@@ -0,0 +1,12 @@
+package loghelper
+
+import (
+	log "github.com/sirupsen/logrus"
+)
+
+// A simple helper function that will help wrap the error message.
+func LogEndpoint(endpoint string) *log.Entry {
+	return log.WithFields(log.Fields{
+		"endpoint": endpoint,
+	})
+}

pkg/loghelper/log_error.go

@@ -11,3 +11,10 @@ func LogError(err error) *log.Entry {
 		"err": err,
 	})
 }
+
+func LogSlotError(slot string, err error) *log.Entry {
+	return log.WithFields(log.Fields{
+		"err":  err,
+		"slot": slot,
+	})
+}