cmd, eth: introduce BlockPeriod type for flexible beacon chain simulation

cmd/geth/config.go

@@ -218,7 +218,11 @@ func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend) {
 
 	if ctx.IsSet(utils.DeveloperFlag.Name) {
 		// Start dev mode.
-		simBeacon, err := catalyst.NewSimulatedBeacon(ctx.Uint64(utils.DeveloperPeriodFlag.Name), eth)
+		p, err := catalyst.ParseBlockPeriod(ctx.String(utils.DeveloperFlag.Name))
+		if err != nil {
+			utils.Fatalf("failed to parse developer mode block interval: %v", err)
+		}
+		simBeacon, err := catalyst.NewSimulatedBeacon(p, eth)
 		if err != nil {
 			utils.Fatalf("failed to register dev mode catalyst service: %v", err)
 		}

eth/catalyst/simulated_beacon.go

@@ -36,7 +36,25 @@ import (
 	"github.com/ethereum/go-ethereum/rpc"
 )
 
-const devEpochLength = 32
+const (
+	devEpochLength = 32
+	// ManualPeriod is a special value for the block interval that disables automatic block production, and
+	// requires manual invocation of the Commit, Fork and AdjustTime methods.
+	ManualPeriod = BlockPeriod(0)
+)
+
+type BlockPeriod time.Duration
+
+func ParseBlockPeriod(period string) (BlockPeriod, error) {
+	if period == "0" {
+		return ManualPeriod, nil
+	}
+	d, err := time.ParseDuration(period)
+	if err != nil {
+		return 0, err
+	}
+	return BlockPeriod(d), nil
+}
 
 // withdrawalQueue implements a FIFO queue which holds withdrawals that are
 // pending inclusion.
@@ -74,23 +92,26 @@ func (w *withdrawalQueue) gatherPending(maxCount int) []*types.Withdrawal {
 type SimulatedBeacon struct {
 	shutdownCh  chan struct{}
 	eth         *eth.Ethereum
-	period      uint64
+	period      BlockPeriod
 	withdrawals withdrawalQueue
 
 	feeRecipient     common.Address
 	feeRecipientLock sync.Mutex // lock gates concurrent access to the feeRecipient
 
 	engineAPI          *ConsensusAPI
-	curForkchoiceState engine.ForkchoiceStateV1
+	curForkChoiceState engine.ForkchoiceStateV1
 	lastBlockTime      uint64
 }
 
 // NewSimulatedBeacon constructs a new simulated beacon chain.
 // Period sets the period in which blocks should be produced.
-//
+// Args:
-//   - If period is set to 0, a block is produced on every transaction.
+// - period: the block production period, use ManualPeriod to disable automatic block production and require manual invocation of Commit, Fork and AdjustTime.
-//     via Commit, Fork and AdjustTime.
+// - eth: the Ethereum service to which the simulated beacon should be attached.
-func NewSimulatedBeacon(period uint64, eth *eth.Ethereum) (*SimulatedBeacon, error) {
+// Returns:
+// - a new simulated beacon chain.
+// - an error if the beacon could not be created.
+func NewSimulatedBeacon(period BlockPeriod, eth *eth.Ethereum) (*SimulatedBeacon, error) {
 	block := eth.BlockChain().CurrentBlock()
 	current := engine.ForkchoiceStateV1{
 		HeadBlockHash:      block.Hash(),
@@ -99,7 +120,7 @@ func NewSimulatedBeacon(period uint64, eth *eth.Ethereum) (*SimulatedBeacon, err
 	}
 	engineAPI := newConsensusAPIWithoutHeartbeat(eth)
 
-	// if genesis block, send forkchoiceUpdated to trigger transition to PoS
+	// if genesis block, send forkChoiceUpdated to trigger transition to PoS
 	if block.Number.Sign() == 0 {
 		if _, err := engineAPI.ForkchoiceUpdatedV2(current, nil); err != nil {
 			return nil, err
@@ -111,7 +132,7 @@ func NewSimulatedBeacon(period uint64, eth *eth.Ethereum) (*SimulatedBeacon, err
 		shutdownCh:         make(chan struct{}),
 		engineAPI:          engineAPI,
 		lastBlockTime:      block.Time,
-		curForkchoiceState: current,
+		curForkChoiceState: current,
 		withdrawals:        withdrawalQueue{make(chan *types.Withdrawal, 20)},
 	}, nil
 }
@@ -124,7 +145,7 @@ func (c *SimulatedBeacon) setFeeRecipient(feeRecipient common.Address) {
 
 // Start invokes the SimulatedBeacon life-cycle function in a goroutine.
 func (c *SimulatedBeacon) Start() error {
-	if c.period == 0 {
+	if c.period == ManualPeriod {
 		// if period is set to 0, do not mine at all
 		// this is used in the simulated backend where blocks
 		// are explicitly mined via Commit, AdjustTime and Fork
@@ -151,14 +172,14 @@ func (c *SimulatedBeacon) sealBlock(withdrawals []*types.Withdrawal, timestamp u
 	c.feeRecipientLock.Unlock()
 
 	// Reset to CurrentBlock in case of the chain was rewound
-	if header := c.eth.BlockChain().CurrentBlock(); c.curForkchoiceState.HeadBlockHash != header.Hash() {
+	if header := c.eth.BlockChain().CurrentBlock(); c.curForkChoiceState.HeadBlockHash != header.Hash() {
 		finalizedHash := c.finalizedBlockHash(header.Number.Uint64())
 		c.setCurrentState(header.Hash(), *finalizedHash)
 	}
 
 	var random [32]byte
 	rand.Read(random[:])
-	fcResponse, err := c.engineAPI.forkchoiceUpdated(c.curForkchoiceState, &engine.PayloadAttributes{
+	fcResponse, err := c.engineAPI.forkchoiceUpdated(c.curForkChoiceState, &engine.PayloadAttributes{
 		Timestamp:             timestamp,
 		SuggestedFeeRecipient: feeRecipient,
 		Withdrawals:           withdrawals,
@@ -208,7 +229,7 @@ func (c *SimulatedBeacon) sealBlock(withdrawals []*types.Withdrawal, timestamp u
 	c.setCurrentState(payload.BlockHash, finalizedHash)
 
 	// Mark the block containing the payload as canonical
-	if _, err = c.engineAPI.ForkchoiceUpdatedV2(c.curForkchoiceState, nil); err != nil {
+	if _, err = c.engineAPI.ForkchoiceUpdatedV2(c.curForkChoiceState, nil); err != nil {
 		return err
 	}
 	c.lastBlockTime = payload.Timestamp
@@ -227,7 +248,7 @@ func (c *SimulatedBeacon) loop() {
 			if err := c.sealBlock(withdrawals, uint64(time.Now().Unix())); err != nil {
 				log.Warn("Error performing sealing work", "err", err)
 			} else {
-				timer.Reset(time.Second * time.Duration(c.period))
+				timer.Reset(time.Duration(c.period))
 			}
 		}
 	}
@@ -249,9 +270,9 @@ func (c *SimulatedBeacon) finalizedBlockHash(number uint64) *common.Hash {
 	return nil
 }
 
-// setCurrentState sets the current forkchoice state
+// setCurrentState sets the current fork choice state.
 func (c *SimulatedBeacon) setCurrentState(headHash, finalizedHash common.Hash) {
-	c.curForkchoiceState = engine.ForkchoiceStateV1{
+	c.curForkChoiceState = engine.ForkchoiceStateV1{
 		HeadBlockHash:      headHash,
 		SafeBlockHash:      headHash,
 		FinalizedBlockHash: finalizedHash,
@@ -304,7 +325,7 @@ func (c *SimulatedBeacon) AdjustTime(adjustment time.Duration) error {
 
 func RegisterSimulatedBeaconAPIs(stack *node.Node, sim *SimulatedBeacon) {
 	api := &api{sim}
-	if sim.period == 0 {
+	if sim.period == ManualPeriod {
 		// mine on demand if period is set to 0
 		go api.loop()
 	}

eth/catalyst/simulated_beacon_test.go

@@ -55,7 +55,7 @@ func startSimulatedBeaconEthService(t *testing.T, genesis *core.Genesis) (*node.
 		t.Fatal("can't create eth service:", err)
 	}
 
-	simBeacon, err := NewSimulatedBeacon(1, ethservice)
+	simBeacon, err := NewSimulatedBeacon(BlockPeriod(time.Second), ethservice)
 	if err != nil {
 		t.Fatal("can't create simulated beacon:", err)
 	}

ethclient/simulated/backend.go

@@ -96,7 +96,7 @@ func NewBackend(alloc types.GenesisAlloc, options ...func(nodeConf *node.Config,
 	if err != nil {
 		panic(err) // this should never happen
 	}
-	sim, err := newWithNode(stack, &ethConf, 0)
+	sim, err := newWithNode(stack, &ethConf, catalyst.ManualPeriod)
 	if err != nil {
 		panic(err) // this should never happen
 	}
@@ -105,17 +105,19 @@ func NewBackend(alloc types.GenesisAlloc, options ...func(nodeConf *node.Config,
 
 // newWithNode sets up a simulated backend on an existing node. The provided node
 // must not be started and will be started by this method.
-func newWithNode(stack *node.Node, conf *eth.Config, blockPeriod uint64) (*Backend, error) {
+func newWithNode(stack *node.Node, conf *eth.Config, blockPeriod catalyst.BlockPeriod) (*Backend, error) {
 	backend, err := eth.New(stack, conf)
 	if err != nil {
 		return nil, err
 	}
 	// Register the filter system
 	filterSystem := filters.NewFilterSystem(backend.APIBackend, filters.Config{})
-	stack.RegisterAPIs([]rpc.API{{
+	stack.RegisterAPIs([]rpc.API{
+		{
 			Namespace: "eth",
 			Service:   filters.NewFilterAPI(filterSystem, false),
-	}})
+		},
+	})
 	// Start the node
 	if err := stack.Start(); err != nil {
 		return nil, err