new: Add wiggle to block time

cmd/puppeth/wizard_genesis.go

@@ -111,6 +111,7 @@ func (w *wizard) makeGenesis() {
 			Period:                1,
 			ProducerDelay:         5,
 			Sprint:                60,
+			BackupMultiplier:      1,
 			ValidatorContract:     "0x0000000000000000000000000000000000001000",
 			StateReceiverContract: "0x0000000000000000000000000000000000001001",
 		}

consensus/bor/bor.go

@@ -207,14 +207,18 @@ func CalcDifficulty(snap *Snapshot, signer common.Address, sprint uint64) *big.I
 	return big.NewInt(0).SetUint64(snap.inturn(snap.Number+1, signer, sprint))
 }
 
-// CalcProducerDelay is the block delay algorithm based on block time and period / producerDelay values in genesis
-func CalcProducerDelay(number uint64, period uint64, sprint uint64, producerDelay uint64) uint64 {
+// CalcProducerDelay is the block delay algorithm based on block time, period, producerDelay and turn-ness of a signer
+func CalcProducerDelay(number uint64, succession int, c *params.BorConfig) uint64 {
 	// When the block is the first block of the sprint, it is expected to be delayed by `producerDelay`.
 	// That is to allow time for block propagation in the last sprint
-	if number%sprint == 0 {
-		return producerDelay
+	delay := c.Period
+	if number%c.Sprint == 0 {
+		delay = c.ProducerDelay
 	}
-	return period
+	if succession > 0 {
+		delay += uint64(succession) * c.BackupMultiplier
+	}
+	return delay
 }
 
 // BorRLP returns the rlp bytes which needs to be signed for the bor
@@ -334,17 +338,6 @@ func (c *Bor) verifyHeader(chain consensus.ChainReader, header *types.Header, pa
 	}
 	number := header.Number.Uint64()
 
-	var parent *types.Header
-	if len(parents) > 0 { // if parents is nil, len(parents) is zero
-		parent = parents[len(parents)-1]
-	} else if number > 0 {
-		parent = chain.GetHeader(header.ParentHash, number-1)
-	}
-
-	if parent != nil && header.Time < parent.Time+CalcProducerDelay(number, c.config.Period, c.config.Sprint, c.config.ProducerDelay) {
-		return consensus.ErrBlockTooSoon
-	}
-
 	// Don't waste time checking blocks from the future
 	if header.Time > uint64(time.Now().Unix()) {
 		return consensus.ErrFutureBlock
@@ -590,10 +583,22 @@ func (c *Bor) verifySeal(chain consensus.ChainReader, header *types.Header, pare
 		return errUnauthorizedSigner
 	}
 
-	if _, err = snap.GetSignerSuccessionNumber(signer); err != nil {
+	succession, err := snap.GetSignerSuccessionNumber(signer)
+	if err != nil {
 		return err
 	}
 
+	var parent *types.Header
+	if len(parents) > 0 { // if parents is nil, len(parents) is zero
+		parent = parents[len(parents)-1]
+	} else if number > 0 {
+		parent = chain.GetHeader(header.ParentHash, number-1)
+	}
+
+	if parent != nil && header.Time < parent.Time+CalcProducerDelay(number, succession, c.config) {
+		return &BlockTooSoonError{number, succession}
+	}
+
 	// Ensure that the difficulty corresponds to the turn-ness of the signer
 	if !c.fakeDiff {
 		difficulty := snap.inturn(header.Number.Uint64(), signer, c.config.Sprint)
@@ -654,7 +659,11 @@ func (c *Bor) Prepare(chain consensus.ChainReader, header *types.Header) error {
 		return consensus.ErrUnknownAncestor
 	}
 
-	header.Time = parent.Time + CalcProducerDelay(number, c.config.Period, c.config.Sprint, c.config.ProducerDelay)
+	succession, err := snap.GetSignerSuccessionNumber(c.signer)
+	if err != nil {
+		return err
+	}
+	header.Time = parent.Time + CalcProducerDelay(number, succession, c.config)
 	if header.Time < uint64(time.Now().Unix()) {
 		header.Time = uint64(time.Now().Unix())
 	}
@@ -765,8 +774,8 @@ func (c *Bor) Seal(chain consensus.ChainReader, block *types.Block, results chan
 
 	// Sweet, the protocol permits us to sign the block, wait for our time
 	delay := time.Unix(int64(header.Time), 0).Sub(time.Now()) // nolint: gosimple
-	wiggle := time.Duration(2*c.config.Period) * time.Second * time.Duration(successionNumber)
-	delay += wiggle
+	// wiggle was already accounted for in header.Time, this is just for logging
+	wiggle := time.Duration(successionNumber) * time.Duration(c.config.BackupMultiplier) * time.Second
 
 	// Sign all the things!
 	sighash, err := signFn(accounts.Account{Address: signer}, accounts.MimetypeBor, BorRLP(header))

consensus/bor/bor_test/bor_test.go

@@ -24,11 +24,7 @@ func TestCommitSpan(t *testing.T) {
 	// Mock HeimdallClient.FetchWithRetry to return span data from span.json
 	res, heimdallSpan := loadSpanFromFile(t)
 	h := &mocks.IHeimdallClient{}
-	// FetchWithRetry is invoked 3 times
-	// 1. bor.FinalizeAndAssemble to prepare a new block when calling insertNewBlock
-	// 2. bor.Finalize via(bc.insertChain => bc.processor.Process)
-	// 3. bor.FinalizeAndAssemble via worker.commit
-	h.On("FetchWithRetry", "bor", "span", "1").Return(res, nil).Times(3)
+	h.On("FetchWithRetry", "bor", "span", "1").Return(res, nil)
 	_bor.SetHeimdallClient(h)
 
 	db := init.ethereum.ChainDb()
@@ -45,7 +41,10 @@ func TestCommitSpan(t *testing.T) {
 		block = insertNewBlock(t, _bor, chain, header, statedb, _key)
 	}
 
-	assert.True(t, h.AssertNumberOfCalls(t, "FetchWithRetry", 3))
+	// FetchWithRetry is invoked 2 times
+	// 1. bor.FinalizeAndAssemble to prepare a new block when calling insertNewBlock
+	// 2. bor.Finalize via(bc.insertChain => bc.processor.Process)
+	assert.True(t, h.AssertNumberOfCalls(t, "FetchWithRetry", 2))
 	validators, err := _bor.GetCurrentValidators(sprintSize, 256) // new span starts at 256
 	if err != nil {
 		t.Fatalf("%s", err)

consensus/bor/bor_test/genesis.json

@@ -11,6 +11,7 @@
     "bor": {
       "period": 1,
       "producerDelay": 4,
+      "backupMultiplier": 1,
       "sprint": 4,
       "validatorContract": "0x0000000000000000000000000000000000001000",
       "stateReceiverContract": "0x0000000000000000000000000000000000001001"

consensus/bor/bor_test/helper.go

@@ -111,7 +111,7 @@ func buildMinimalNextHeader(t *testing.T, block *types.Block, borConfig *params.
 	header := block.Header()
 	header.Number.Add(header.Number, big.NewInt(1))
 	header.ParentHash = block.Hash()
-	header.Time += bor.CalcProducerDelay(header.Number.Uint64(), borConfig.Period, borConfig.Sprint, borConfig.ProducerDelay)
+	header.Time += bor.CalcProducerDelay(header.Number.Uint64(), 0, borConfig)
 	header.Extra = make([]byte, 32+65) // vanity + extraSeal
 
 	currentValidators := []*bor.Validator{bor.NewValidator(addr, 10)}

consensus/bor/errors.go

@@ -96,3 +96,16 @@ func (e *MismatchingValidatorsError) Error() string {
 		e.ValidatorSetHeader,
 	)
 }
+
+type BlockTooSoonError struct {
+	Number     uint64
+	Succession int
+}
+
+func (e *BlockTooSoonError) Error() string {
+	return fmt.Sprintf(
+		"Block %d was created too soon. Signer turn-ness number is %d\n",
+		e.Number,
+		e.Succession,
+	)
+}

params/config.go

@@ -319,6 +319,7 @@ type BorConfig struct {
 	Period                uint64 `json:"period"`                // Number of seconds between blocks to enforce
 	ProducerDelay         uint64 `json:"producerDelay"`         // Number of seconds delay between two producer interval
 	Sprint                uint64 `json:"sprint"`                // Epoch length to proposer
+	BackupMultiplier      uint64 `json:"backupMultiplier"`      // Backup multiplier to determine the wiggle time
 	ValidatorContract     string `json:"validatorContract"`     // Validator set contract
 	StateReceiverContract string `json:"stateReceiverContract"` // State receiver contract
 }