Only set metrics.Enabled in VM.Initalize

metrics/prometheus/prometheus.go

@@ -16,10 +16,6 @@ import (
 	dto "github.com/prometheus/client_model/go"
 )
 
-func init() {
-	metrics.Enabled = true
-}
-
 type Gatherer struct {
 	registry Registry
 }

plugin/evm/config/config.go

@@ -27,6 +27,7 @@ const (
 	defaultSnapshotWait                           = false
 	defaultRpcGasCap                              = 50_000_000 // Default to 50M Gas Limit
 	defaultRpcTxFeeCap                            = 100        // 100 AVAX
+	defaultMetricsEnabled                         = true
 	defaultMetricsExpensiveEnabled                = true
 	defaultApiMaxDuration                         = 0 // Default to no maximum API call duration
 	defaultWsCpuRefillRate                        = 0 // Default to no maximum WS CPU usage
@@ -125,7 +126,8 @@ type Config struct {
 	PruneWarpDB                     bool    `json:"prune-warp-db-enabled"`              // Determines if the warpDB should be cleared on startup
 
 	// Metric Settings
-	MetricsExpensiveEnabled bool `json:"metrics-expensive-enabled"` // Debug-level metrics that might impact runtime performance
+	MetricsEnabled          *bool `json:"metrics-enabled,omitempty"`
+	MetricsExpensiveEnabled bool  `json:"metrics-expensive-enabled"` // Debug-level metrics that might impact runtime performance
 
 	// API Settings
 	LocalTxsEnabled bool `json:"local-txs-enabled"`
@@ -243,6 +245,7 @@ func (c *Config) SetDefaults(txPoolConfig TxPoolConfig) {
 	c.EnabledEthAPIs = defaultEnabledAPIs
 	c.RPCGasCap = defaultRpcGasCap
 	c.RPCTxFeeCap = defaultRpcTxFeeCap
+	c.MetricsEnabled = defaultPointer(c.MetricsEnabled, defaultMetricsEnabled)
 	c.MetricsExpensiveEnabled = defaultMetricsExpensiveEnabled
 
 	// TxPool settings
@@ -290,6 +293,13 @@ func (c *Config) SetDefaults(txPoolConfig TxPoolConfig) {
 	c.AcceptedCacheSize = defaultAcceptedCacheSize
 }
 
+func defaultPointer[T any](existing *T, defaultValue T) (updated *T) {
+	if existing != nil {
+		return existing
+	}
+	return &defaultValue
+}
+
 func (d *Duration) UnmarshalJSON(data []byte) (err error) {
 	var v interface{}
 	if err := json.Unmarshal(data, &v); err != nil {

plugin/evm/syncervm_test.go

@@ -35,6 +35,7 @@ import (
 	"github.com/ava-labs/coreth/core/types"
 	"github.com/ava-labs/coreth/params"
 	"github.com/ava-labs/coreth/plugin/evm/atomic"
+	"github.com/ava-labs/coreth/plugin/evm/config"
 	"github.com/ava-labs/coreth/plugin/evm/database"
 	"github.com/ava-labs/coreth/predicate"
 	statesyncclient "github.com/ava-labs/coreth/sync/client"
@@ -44,7 +45,6 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/log"
-	"github.com/ethereum/go-ethereum/metrics"
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
@@ -85,13 +85,10 @@ func TestStateSyncFromScratchExceedParent(t *testing.T) {
 	testSyncerVM(t, vmSetup, test)
 }
 
+func pointerTo[T any](x T) *T { return &x }
+
 func TestStateSyncToggleEnabledToDisabled(t *testing.T) {
 	rand.Seed(1)
-	// Hack: registering metrics uses global variables, so we need to disable metrics here so that we can initialize the VM twice.
-	metrics.Enabled = false
-	defer func() {
-		metrics.Enabled = true
-	}()
 
 	var lock sync.Mutex
 	reqCount := 0
@@ -130,7 +127,11 @@ func TestStateSyncToggleEnabledToDisabled(t *testing.T) {
 	test.responseIntercept = nil
 	test.expectedErr = nil
 
-	syncDisabledVM := &VM{}
+	syncDisabledVM := &VM{
+		config: config.Config{
+			MetricsEnabled: pointerTo(false),
+		},
+	}
 	appSender := &enginetest.Sender{T: t}
 	appSender.SendAppGossipF = func(context.Context, commonEng.SendConfig, []byte) error { return nil }
 	appSender.SendAppRequestF = func(ctx context.Context, nodeSet set.Set[ids.NodeID], requestID uint32, request []byte) error {
@@ -200,7 +201,9 @@ func TestStateSyncToggleEnabledToDisabled(t *testing.T) {
 	syncDisabledVM.blockChain.DrainAcceptorQueue()
 
 	// Create a new VM from the same database with state sync enabled.
-	syncReEnabledVM := &VM{}
+	syncReEnabledVM := &VM{
+		config: config.Config{MetricsEnabled: pointerTo(false)},
+	}
 	// Enable state sync in configJSON
 	configJSON := fmt.Sprintf(
 		`{"state-sync-enabled":true, "state-sync-min-blocks":%d}`,

plugin/evm/vm.go

@@ -24,6 +24,7 @@ import (
 	"github.com/ava-labs/avalanchego/upgrade"
 	avalanchegoConstants "github.com/ava-labs/avalanchego/utils/constants"
 	"github.com/prometheus/client_golang/prometheus"
+	dto "github.com/prometheus/client_model/go"
 
 	"github.com/ava-labs/coreth/consensus/dummy"
 	"github.com/ava-labs/coreth/constants"
@@ -279,7 +280,10 @@ type VM struct {
 	p2pValidators *p2p.Validators
 
 	// Metrics
-	sdkMetrics *prometheus.Registry
+	sdkMetrics interface {
+		prometheus.Registerer
+		prometheus.Gatherer
+	}
 
 	bootstrapped avalancheUtils.Atomic[bool]
 	IsPlugin     bool
@@ -390,8 +394,13 @@ func (vm *VM) Initialize(
 	vm.toEngine = toEngine
 	vm.shutdownChan = make(chan struct{}, 1)
 
-	if err := vm.initializeMetrics(); err != nil {
-		return fmt.Errorf("failed to initialize metrics: %w", err)
+	if *vm.config.MetricsEnabled {
+		if err := vm.initializeMetrics(); err != nil {
+			return fmt.Errorf("failed to initialize metrics: %w", err)
+		}
+	} else {
+		metrics.Enabled = false // reset global variable to false for tests
+		vm.sdkMetrics = &noopPrometheusRegister{}
 	}
 
 	// Initialize the database
@@ -630,19 +639,22 @@ func (vm *VM) Initialize(
 }
 
 func (vm *VM) initializeMetrics() error {
+	metrics.Enabled = true
 	vm.sdkMetrics = prometheus.NewRegistry()
-	// If metrics are enabled, register the default metrics registry
-	if !metrics.Enabled {
-		return nil
-	}
-
 	gatherer := corethprometheus.NewGatherer(metrics.DefaultRegistry)
 	if err := vm.ctx.Metrics.Register(ethMetricsPrefix, gatherer); err != nil {
 		return err
 	}
 	return vm.ctx.Metrics.Register(sdkMetricsPrefix, vm.sdkMetrics)
 }
 
+type noopPrometheusRegister struct{}
+
+func (n *noopPrometheusRegister) Register(prometheus.Collector) error  { return nil }
+func (n *noopPrometheusRegister) MustRegister(...prometheus.Collector) {}
+func (n *noopPrometheusRegister) Unregister(prometheus.Collector) bool { return true }
+func (n *noopPrometheusRegister) Gather() ([]*dto.MetricFamily, error) { return nil, nil }
+
 func (vm *VM) initializeChain(lastAcceptedHash common.Hash) error {
 	nodecfg := &node.Config{
 		CorethVersion:         Version,

plugin/evm/vm_test.go

@@ -27,7 +27,6 @@ import (
 	"github.com/ava-labs/coreth/plugin/evm/config"
 	"github.com/ava-labs/coreth/trie"
 	"github.com/ava-labs/coreth/utils"
-	"github.com/ethereum/go-ethereum/metrics"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -306,7 +305,13 @@ func GenesisVMWithClock(
 	*avalancheatomic.Memory,
 	*enginetest.Sender,
 ) {
-	vm := &VM{clock: clock}
+	vmConfig := config.Config{
+		MetricsEnabled: pointerTo(false),
+	}
+	vm := &VM{
+		clock:  clock,
+		config: vmConfig,
+	}
 	ctx, dbManager, genesisBytes, issuer, m := setupGenesis(t, genesisJSON)
 	appSender := &enginetest.Sender{T: t}
 	appSender.CantSendAppGossip = true
@@ -402,6 +407,7 @@ func TestVMConfigDefaults(t *testing.T) {
 	_, vm, _, _, _ := GenesisVM(t, false, "", configJSON, "")
 
 	var vmConfig config.Config
+	vmConfig.MetricsEnabled = pointerTo(false) // GenesisVM sets it to false
 	vmConfig.SetDefaults(defaultTxPoolConfig)
 	vmConfig.RPCTxFeeCap = txFeeCap
 	vmConfig.EnabledEthAPIs = enabledEthAPIs
@@ -414,6 +420,7 @@ func TestVMNilConfig(t *testing.T) {
 
 	// VM Config should match defaults if no config is passed in
 	var vmConfig config.Config
+	vmConfig.MetricsEnabled = pointerTo(false) // GenesisVM sets it to false
 	vmConfig.SetDefaults(defaultTxPoolConfig)
 	require.Equal(t, vmConfig, vm.config, "VM Config should match default config")
 	require.NoError(t, vm.Shutdown(context.Background()))
@@ -3780,10 +3787,6 @@ func TestExtraStateChangeAtomicGasLimitExceeded(t *testing.T) {
 }
 
 func TestSkipChainConfigCheckCompatible(t *testing.T) {
-	// Hack: registering metrics uses global variables, so we need to disable metrics here so that we can initialize the VM twice.
-	metrics.Enabled = false
-	defer func() { metrics.Enabled = true }()
-
 	importAmount := uint64(50000000)
 	issuer, vm, dbManager, _, appSender := GenesisVMWithUTXOs(t, true, genesisJSONApricotPhase1, "", "", map[ids.ShortID]uint64{
 		testShortIDAddrs[0]: importAmount,
@@ -3803,7 +3806,12 @@ func TestSkipChainConfigCheckCompatible(t *testing.T) {
 	require.NoError(t, vm.SetPreference(context.Background(), blk.ID()))
 	require.NoError(t, blk.Accept(context.Background()))
 
-	reinitVM := &VM{}
+	reinitVM := &VM{
+		// Hack: registering metrics uses global variables, so we need to disable metrics so that we can initialize the VM twice.
+		config: config.Config{
+			MetricsEnabled: pointerTo(false),
+		},
+	}
 	// use the block's timestamp instead of 0 since rewind to genesis
 	// is hardcoded to be allowed in core/genesis.go.
 	genesisWithUpgrade := &core.Genesis{}
@@ -3817,7 +3825,7 @@ func TestSkipChainConfigCheckCompatible(t *testing.T) {
 	require.ErrorContains(t, err, "mismatching ApricotPhase2 fork block timestamp in database")
 
 	// try again with skip-upgrade-check
-	config := []byte(`{"skip-upgrade-check": true}`)
+	config := []byte(`{"skip-upgrade-check": true, "metrics-enabled": false}`)
 	err = reinitVM.Initialize(context.Background(), vm.ctx, dbManager, genesisWithUpgradeBytes, []byte{}, config, issuer, []*commonEng.Fx{}, appSender)
 	require.NoError(t, err)
 	require.NoError(t, reinitVM.Shutdown(context.Background()))