Update state metrics on save state (#2083)

* Update state metrics on save state

* fix tests

beacon-chain/blockchain/fork_choice_test.go

@@ -491,6 +491,7 @@ func TestLMDGhost_TrivialHeadUpdate(t *testing.T) {
 	state := &pb.BeaconState{
 		Slot:              10,
 		ValidatorBalances: []uint64{params.BeaconConfig().MaxDepositAmount},
+		ValidatorRegistry: []*pb.Validator{{}},
 	}
 
 	chainService := setupBeaconChain(t, false, beaconDB, true, nil)
@@ -548,6 +549,7 @@ func TestLMDGhost_3WayChainSplitsSameHeight(t *testing.T) {
 			params.BeaconConfig().MaxDepositAmount,
 			params.BeaconConfig().MaxDepositAmount,
 			params.BeaconConfig().MaxDepositAmount},
+		ValidatorRegistry: []*pb.Validator{{}, {}, {}, {}},
 	}
 
 	chainService := setupBeaconChain(t, false, beaconDB, true, nil)
@@ -631,6 +633,7 @@ func TestLMDGhost_2WayChainSplitsDiffHeight(t *testing.T) {
 			params.BeaconConfig().MaxDepositAmount,
 			params.BeaconConfig().MaxDepositAmount,
 			params.BeaconConfig().MaxDepositAmount},
+		ValidatorRegistry: []*pb.Validator{{}, {}, {}, {}},
 	}
 
 	chainService := setupBeaconChain(t, false, beaconDB, true, nil)

beacon-chain/core/state/BUILD.bazel

@@ -3,7 +3,6 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 go_library(
     name = "go_default_library",
     srcs = [
-        "metrics.go",
         "state.go",
         "transition.go",
     ],
@@ -20,8 +19,6 @@ go_library(
         "//shared/featureconfig:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/params:go_default_library",
-        "@com_github_prometheus_client_golang//prometheus:go_default_library",
-        "@com_github_prometheus_client_golang//prometheus/promauto:go_default_library",
         "@com_github_sirupsen_logrus//:go_default_library",
         "@io_opencensus_go//trace:go_default_library",
     ],
@@ -30,7 +27,6 @@ go_library(
 go_test(
     name = "go_default_test",
     srcs = [
-        "metrics_test.go",
         "state_test.go",
         "transition_test.go",
     ],
@@ -43,6 +39,5 @@ go_test(
         "//shared/forkutil:go_default_library",
         "//shared/hashutil:go_default_library",
         "//shared/params:go_default_library",
-        "@com_github_prometheus_client_golang//prometheus/testutil:go_default_library",
     ],
 )

beacon-chain/core/state/metrics_test.go

@@ -1,33 +0,0 @@
-package state
-
-import (
-	"strings"
-	"testing"
-
-	"github.com/prometheus/client_golang/prometheus/testutil"
-	pb "github.com/prysmaticlabs/prysm/proto/beacon/p2p/v1"
-)
-
-func TestReportEpochTransitionMetrics_validatorBalances(t *testing.T) {
-	state := &pb.BeaconState{
-		ValidatorBalances: []uint64{1, 15},
-		ValidatorRegistry: []*pb.Validator{
-			{Pubkey: []byte{1}},
-			{Pubkey: []byte{2}},
-		},
-	}
-
-	reportEpochTransitionMetrics(state)
-	expectedMetadata := `
-	  # HELP state_validator_balances Balances of validators, updated on epoch transition
-	  # TYPE state_validator_balances gauge
-	`
-	expectedValues := `
-		state_validator_balances{validator="0x01"} 1
-		state_validator_balances{validator="0x02"} 15
-	`
-	expected := expectedMetadata + expectedValues
-	if err := testutil.CollectAndCompare(validatorBalancesGauge, strings.NewReader(expected)); err != nil {
-		t.Error(err)
-	}
-}

beacon-chain/core/state/transition.go

@@ -466,7 +466,5 @@ func ProcessEpoch(ctx context.Context, state *pb.BeaconState, config *Transition
 		log.Infof("Validator balances: %v", state.ValidatorBalances)
 	}
 
-	// Report interesting metrics.
-	reportEpochTransitionMetrics(state)
 	return state, nil
 }

beacon-chain/db/BUILD.bazel

@@ -13,6 +13,7 @@ go_library(
         "schema.go",
         "setup_db.go",
         "state.go",
+        "state_metrics.go",
         "validator.go",
         "verify_contract.go",
     ],

beacon-chain/db/state.go

@@ -148,6 +148,7 @@ func (db *BeaconDB) SaveState(beaconState *pb.BeaconState) error {
 			return err
 		}
 		stateBytes.Set(float64(len(beaconStateEnc)))
+		reportStateMetrics(beaconState)
 		return chainInfo.Put(stateLookupKey, beaconStateEnc)
 	})
 }

beacon-chain/db/state_metrics.go

@@ -1,4 +1,4 @@
-package state
+package db
 
 import (
 	"encoding/hex"
@@ -34,7 +34,7 @@ var (
 	})
 )
 
-func reportEpochTransitionMetrics(state *pb.BeaconState) {
+func reportStateMetrics(state *pb.BeaconState) {
 	// Validator balances
 	for i, bal := range state.ValidatorBalances {
 		validatorBalancesGauge.WithLabelValues(