op-node: implement metered EngineControl, a wrapper to capture engine building metrics

op-node/rollup/driver/metered_engine.go

+package driver
+
+import (
+	"context"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+
+	"github.com/ethereum-optimism/optimism/op-node/eth"
+	"github.com/ethereum-optimism/optimism/op-node/rollup"
+	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
+)
+
+type EngineMetrics interface {
+	RecordSequencingError()
+	CountSequencedTxs(count int)
+
+	RecordSequencerBuildingDiffTime(duration time.Duration)
+	RecordSequencerSealingTime(duration time.Duration)
+}
+
+// MeteredEngine wraps an EngineControl and adds metrics such as block building time diff and sealing time
+type MeteredEngine struct {
+	inner derive.EngineControl
+
+	cfg     *rollup.Config
+	metrics EngineMetrics
+	log     log.Logger
+
+	buildingStartTime time.Time
+}
+
+// MeteredEngine implements derive.EngineControl
+var _ derive.EngineControl = (*MeteredEngine)(nil)
+
+func NewMeteredEngine(cfg *rollup.Config, inner derive.EngineControl, metrics EngineMetrics, log log.Logger) *MeteredEngine {
+	return &MeteredEngine{
+		inner:   inner,
+		cfg:     cfg,
+		metrics: metrics,
+		log:     log,
+	}
+}
+
+func (m *MeteredEngine) Finalized() eth.L2BlockRef {
+	return m.inner.Finalized()
+}
+
+func (m *MeteredEngine) UnsafeL2Head() eth.L2BlockRef {
+	return m.inner.UnsafeL2Head()
+}
+
+func (m *MeteredEngine) SafeL2Head() eth.L2BlockRef {
+	return m.inner.SafeL2Head()
+}
+
+func (m *MeteredEngine) StartPayload(ctx context.Context, parent eth.L2BlockRef, attrs *eth.PayloadAttributes, updateSafe bool) (errType derive.BlockInsertionErrType, err error) {
+	m.buildingStartTime = time.Now()
+	errType, err = m.inner.StartPayload(ctx, parent, attrs, updateSafe)
+	if err != nil {
+		m.metrics.RecordSequencingError()
+	}
+	return errType, err
+}
+
+func (m *MeteredEngine) ConfirmPayload(ctx context.Context) (out *eth.ExecutionPayload, errTyp derive.BlockInsertionErrType, err error) {
+	sealingStart := time.Now()
+	// Actually execute the block and add it to the head of the chain.
+	payload, errType, err := m.inner.ConfirmPayload(ctx)
+	if err != nil {
+		m.metrics.RecordSequencingError()
+		return payload, errType, err
+	}
+	now := time.Now()
+	sealTime := now.Sub(sealingStart)
+	buildTime := now.Sub(m.buildingStartTime)
+	m.metrics.RecordSequencerSealingTime(sealTime)
+	m.metrics.RecordSequencerBuildingDiffTime(buildTime - time.Duration(m.cfg.BlockTime)*time.Second)
+	m.metrics.CountSequencedTxs(len(payload.Transactions))
+
+	ref := m.inner.UnsafeL2Head()
+
+	m.log.Debug("Processed new L2 block", "l2_unsafe", ref, "l1_origin", ref.L1Origin,
+		"txs", len(payload.Transactions), "time", ref.Time, "seal_time", sealTime, "build_time", buildTime)
+
+	return payload, errType, err
+}
+
+func (m *MeteredEngine) CancelPayload(ctx context.Context, force bool) error {
+	return m.inner.CancelPayload(ctx, force)
+}
+
+func (m *MeteredEngine) BuildingPayload() (onto eth.L2BlockRef, id eth.PayloadID, safe bool) {
+	return m.inner.BuildingPayload()
+}