core: remove ticker parameter from NewConsensus

- remove BlockProposingInterval, it's replaced
  by lambda.
- remove ticker parameter of NewConsensus,
  ticker would be derived from governance.
- leave a backdoor to hook the construction
  of ticker.
- move 'Lambda' config from to consensus.

10 files changed, 113 insertions, 53 deletions

diff --git a/core/consensus.go b/core/consensus.go
index 5e56ab9..6f59638 100644
--- a/core/consensus.go
+++ b/core/consensus.go
@@ -124,7 +124,7 @@ type Consensus struct {
 	ccModule  *compactionChain
 	db        blockdb.BlockDatabase
 	network   Network
-	tick      *time.Ticker
+	tickerObj Ticker
 	prvKey    crypto.PrivateKey
 	sigToPub  SigToPubFn
 	lock      sync.RWMutex
@@ -138,7 +138,6 @@ func NewConsensus(
 	gov Governance,
 	db blockdb.BlockDatabase,
 	network Network,
-	tick *time.Ticker,
 	prv crypto.PrivateKey,
 	sigToPub SigToPubFn) *Consensus {
 	validatorSet := gov.GetValidatorSet()
@@ -172,7 +171,7 @@ func NewConsensus(
 		gov:       gov,
 		db:        db,
 		network:   network,
-		tick:      tick,
+		tickerObj: newTicker(gov),
 		prvKey:    prv,
 		sigToPub:  sigToPub,
 		ctx:       ctx,
@@ -202,7 +201,6 @@ func NewConsensus(
 			blockProposer,
 		)
 	}
-
 	return con
 }
 
@@ -216,10 +214,10 @@ func (con *Consensus) Run() {
 	}
 	go con.processMsg(con.network.ReceiveChan(), con.PreProcessBlock)
 	// Reset ticker.
-	<-con.tick.C
-	<-con.tick.C
+	<-con.tickerObj.Tick()
+	<-con.tickerObj.Tick()
 	for {
-		<-con.tick.C
+		<-con.tickerObj.Tick()
 		for _, tick := range ticks {
 			go func(tick chan struct{}) { tick <- struct{}{} }(tick)
 		}
@@ -302,7 +300,7 @@ func (con *Consensus) RunLegacy() {
 ProposingBlockLoop:
 	for {
 		select {
-		case <-con.tick.C:
+		case <-con.tickerObj.Tick():
 		case <-con.ctx.Done():
 			break ProposingBlockLoop
 		}
diff --git a/core/consensus_test.go b/core/consensus_test.go
index 1e97993..e799675 100644
--- a/core/consensus_test.go
+++ b/core/consensus_test.go
@@ -83,8 +83,7 @@ func (s *ConsensusTestSuite) prepareConsensus(
 	s.Require().Nil(err)
 	prv, exist := gov.PrivateKeys[vID]
 	s.Require().True(exist)
-	con := NewConsensus(app, gov, db,
-		&network{}, time.NewTicker(1), prv, eth.SigToPub)
+	con := NewConsensus(app, gov, db, &network{}, prv, eth.SigToPub)
 	return &con.app, con
 }
 
@@ -102,7 +101,7 @@ func (s *ConsensusTestSuite) TestSimpleDeliverBlock() {
 	// This test case only works for Total Ordering with K=0.
 	var (
 		minInterval = 50 * time.Millisecond
-		gov, err    = test.NewGovernance(4, 1000)
+		gov, err    = test.NewGovernance(4, time.Second)
 		req         = s.Require()
 		validators  []types.ValidatorID
 	)
@@ -325,7 +324,7 @@ func (s *ConsensusTestSuite) TestPrepareBlock() {
 	//  - Make sure Consensus.PrepareBlock would only attempt to
 	//    ack the prepared block.
 	var (
-		gov, err   = test.NewGovernance(4, 1000)
+		gov, err   = test.NewGovernance(4, time.Second)
 		req        = s.Require()
 		validators []types.ValidatorID
 	)
@@ -381,7 +380,7 @@ func (s *ConsensusTestSuite) TestPrepareBlock() {
 
 func (s *ConsensusTestSuite) TestPrepareGenesisBlock() {
 	var (
-		gov, err   = test.NewGovernance(4, 1000)
+		gov, err   = test.NewGovernance(4, time.Second)
 		validators []types.ValidatorID
 	)
 	s.Require().Nil(err)
diff --git a/core/interfaces.go b/core/interfaces.go
index 68f210e..2b616ab 100644
--- a/core/interfaces.go
+++ b/core/interfaces.go
@@ -84,9 +84,6 @@ type Governance interface {
 	// Get PhiRatio.
 	GetPhiRatio() float32
 
-	// Get block proposing interval (in milliseconds).
-	GetBlockProposingInterval() int
-
 	// Get Number of shards.
 	GetNumShards() uint32
 
@@ -99,6 +96,9 @@ type Governance interface {
 	// Get configuration change events after an epoch.
 	GetConfigurationChangeEvent(epoch int) []types.ConfigurationChangeEvent
 
+	// Get lambda for BA.
+	GetLambda() time.Duration
+
 	// AddDKGComplaint adds a DKGComplaint.
 	AddDKGComplaint(complaint *types.DKGComplaint)
 
@@ -111,3 +111,11 @@ type Governance interface {
 	// DKGMasterPublicKeys gets all the DKGMasterPublicKey of round.
 	DKGMasterPublicKeys(round uint64) []*types.DKGMasterPublicKey
 }
+
+// Ticker define the capability to tick by interval.
+type Ticker interface {
+	// Tick would return a channel, which would be triggered until next tick.
+	Tick() <-chan time.Time
+	// Stop the ticker.
+	Stop()
+}
diff --git a/core/test/governance.go b/core/test/governance.go
index 64ca39f..1658e46 100644
--- a/core/test/governance.go
+++ b/core/test/governance.go
@@ -19,6 +19,7 @@ package test
 
 import (
 	"fmt"
+	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
 	"github.com/dexon-foundation/dexon-consensus-core/crypto"
@@ -34,22 +35,22 @@ var (
 
 // Governance is an implementation of Goverance for testing purpose.
 type Governance struct {
-	BlockProposingInterval int
-	Validators             map[types.ValidatorID]decimal.Decimal
-	PrivateKeys            map[types.ValidatorID]crypto.PrivateKey
-	DKGComplaint           map[uint64][]*types.DKGComplaint
-	DKGMasterPublicKey     map[uint64][]*types.DKGMasterPublicKey
+	Lambda             time.Duration
+	Validators         map[types.ValidatorID]decimal.Decimal
+	PrivateKeys        map[types.ValidatorID]crypto.PrivateKey
+	DKGComplaint       map[uint64][]*types.DKGComplaint
+	DKGMasterPublicKey map[uint64][]*types.DKGMasterPublicKey
 }
 
 // NewGovernance constructs a Governance instance.
-func NewGovernance(validatorCount, proposingInterval int) (
+func NewGovernance(validatorCount int, lambda time.Duration) (
 	g *Governance, err error) {
 	g = &Governance{
-		BlockProposingInterval: proposingInterval,
-		Validators:             make(map[types.ValidatorID]decimal.Decimal),
-		PrivateKeys:            make(map[types.ValidatorID]crypto.PrivateKey),
-		DKGComplaint:           make(map[uint64][]*types.DKGComplaint),
-		DKGMasterPublicKey:     make(map[uint64][]*types.DKGMasterPublicKey),
+		Lambda:             lambda,
+		Validators:         make(map[types.ValidatorID]decimal.Decimal),
+		PrivateKeys:        make(map[types.ValidatorID]crypto.PrivateKey),
+		DKGComplaint:       make(map[uint64][]*types.DKGComplaint),
+		DKGMasterPublicKey: make(map[uint64][]*types.DKGMasterPublicKey),
 	}
 	for i := 0; i < validatorCount; i++ {
 		prv, err := eth.NewPrivateKey()
@@ -69,12 +70,6 @@ func (g *Governance) GetValidatorSet() map[types.ValidatorID]decimal.Decimal {
 	return g.Validators
 }
 
-// GetBlockProposingInterval implements Governance interface to return maximum
-// allowed block proposing interval in millisecond.
-func (g *Governance) GetBlockProposingInterval() int {
-	return g.BlockProposingInterval
-}
-
 // GetTotalOrderingK returns K.
 func (g *Governance) GetTotalOrderingK() int {
 	return 0
@@ -107,8 +102,13 @@ func (g *Governance) GetGenesisCRS() string {
 	return "🆕 DEXON"
 }
 
+// GetLambda returns lambda for BA.
+func (g *Governance) GetLambda() time.Duration {
+	return g.Lambda
+}
+
 // GetPrivateKey return the private key for that validator, this function
-// is a test utility and not a general core.Governance interface.
+// is a test utility and not a general Governance interface.
 func (g *Governance) GetPrivateKey(
 	vID types.ValidatorID) (key crypto.PrivateKey, err error) {
 
diff --git a/core/ticker.go b/core/ticker.go
new file mode 100644
index 0000000..dffd676
--- /dev/null
+++ b/core/ticker.go
@@ -0,0 +1,58 @@
+// Copyright 2018 The dexon-consensus-core Authors
+// This file is part of the dexon-consensus-core library.
+//
+// The dexon-consensus-core library is free software: you can redistribute it
+// and/or modify it under the terms of the GNU Lesser General Public License as
+// published by the Free Software Foundation, either version 3 of the License,
+// or (at your option) any later version.
+//
+// The dexon-consensus-core library is distributed in the hope that it will be
+// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+// General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the dexon-consensus-core library. If not, see
+// <http://www.gnu.org/licenses/>.
+
+package core
+
+import "time"
+
+// defaultTicker is a wrapper to implement ticker interface based on
+// time.Ticker.
+type defaultTicker struct {
+	ticker *time.Ticker
+}
+
+// newDefaultTicker constructs an defaultTicker instance by giving an interval.
+func newDefaultTicker(lambda time.Duration) *defaultTicker {
+	return &defaultTicker{ticker: time.NewTicker(lambda)}
+}
+
+// Tick implements Tick method of ticker interface.
+func (t *defaultTicker) Tick() <-chan time.Time {
+	return t.ticker.C
+}
+
+// Stop implements Stop method of ticker interface.
+func (t *defaultTicker) Stop() {
+	t.ticker.Stop()
+}
+
+// newTicker is a helper to setup a ticker by giving an Governance. If
+// the governace object implements a ticker generator, a ticker from that
+// generator would be returned, else constructs a default one.
+func newTicker(gov Governance) (t Ticker) {
+	type tickerGenerator interface {
+		NewTicker() Ticker
+	}
+
+	if gen, ok := gov.(tickerGenerator); ok {
+		t = gen.NewTicker()
+	}
+	if t == nil {
+		t = newDefaultTicker(gov.GetLambda())
+	}
+	return
+}
diff --git a/integration_test/utils.go b/integration_test/utils.go
index de7e6ab..57bb2bc 100644
--- a/integration_test/utils.go
+++ b/integration_test/utils.go
@@ -1,6 +1,8 @@
 package integration
 
 import (
+	"time"
+
 	"github.com/dexon-foundation/dexon-consensus-core/core/blockdb"
 	"github.com/dexon-foundation/dexon-consensus-core/core/test"
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
@@ -25,7 +27,7 @@ func PrepareValidators(
 	dbs = make(map[types.ValidatorID]blockdb.BlockDatabase)
 	validators = make(map[types.ValidatorID]*Validator)
 
-	gov, err := test.NewGovernance(validatorCount, 700)
+	gov, err := test.NewGovernance(validatorCount, 700*time.Millisecond)
 	if err != nil {
 		return
 	}
diff --git a/integration_test/validator.go b/integration_test/validator.go
index a110ab0..18e5c00 100644
--- a/integration_test/validator.go
+++ b/integration_test/validator.go
@@ -102,8 +102,7 @@ func NewValidator(
 		networkLatency:   networkLatency,
 		proposingLatency: proposingLatency,
 		cons: core.NewConsensus(
-			app, gov,
-			db, &Network{}, time.NewTicker(1), privateKey, eth.SigToPub),
+			app, gov, db, &Network{}, privateKey, eth.SigToPub),
 	}
 }
 
diff --git a/simulation/config/config.go b/simulation/config/config.go
index f8f629b..ceb0abd 100644
--- a/simulation/config/config.go
+++ b/simulation/config/config.go
@@ -40,6 +40,7 @@ type Consensus struct {
 	K          int
 	ChainNum   uint32
 	GenesisCRS string `toml:"genesis_crs"`
+	Lambda     int
 }
 
 // Legacy config.
@@ -53,7 +54,6 @@ type Validator struct {
 	Consensus Consensus
 	Legacy    Legacy
 	Num       int
-	Lambda    int
 	MaxBlock  uint64
 }
 
@@ -96,13 +96,13 @@ func GenerateDefault(path string) error {
 				K:          1,
 				ChainNum:   7,
 				GenesisCRS: "In DEXON we trust.",
+				Lambda:     250,
 			},
 			Legacy: Legacy{
 				ProposeIntervalMean:  500,
 				ProposeIntervalSigma: 50,
 			},
 			Num:      7,
-			Lambda:   250,
 			MaxBlock: math.MaxUint64,
 		},
 		Networking: Networking{
diff --git a/simulation/governance.go b/simulation/governance.go
index 44f679d..79c9119 100644
--- a/simulation/governance.go
+++ b/simulation/governance.go
@@ -20,6 +20,7 @@ package simulation
 import (
 	"fmt"
 	"sync"
+	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/core/types"
 	"github.com/dexon-foundation/dexon-consensus-core/simulation/config"
@@ -38,6 +39,7 @@ type simGovernance struct {
 	crs                   string
 	dkgComplaint          map[uint64][]*types.DKGComplaint
 	dkgMasterPublicKey    map[uint64][]*types.DKGMasterPublicKey
+	lambda                time.Duration
 }
 
 // newSimGovernance returns a new simGovernance instance.
@@ -52,6 +54,7 @@ func newSimGovernance(
 		crs:                consensusConfig.GenesisCRS,
 		dkgComplaint:       make(map[uint64][]*types.DKGComplaint),
 		dkgMasterPublicKey: make(map[uint64][]*types.DKGMasterPublicKey),
+		lambda:             time.Duration(consensusConfig.Lambda) * time.Millisecond,
 	}
 }
 
@@ -107,6 +110,11 @@ func (g *simGovernance) GetGenesisCRS() string {
 	return g.crs
 }
 
+// GetLambda return lambda for BA.
+func (g *simGovernance) GetLambda() time.Duration {
+	return g.lambda
+}
+
 // addValidator add a new validator into the simulated governance contract.
 func (g *simGovernance) addValidator(vID types.ValidatorID) {
 	g.lock.Lock()
diff --git a/simulation/validator.go b/simulation/validator.go
index 137c2c0..12ff308 100644
--- a/simulation/validator.go
+++ b/simulation/validator.go
@@ -20,7 +20,6 @@ package simulation
 import (
 	"fmt"
 	"sort"
-	"time"
 
 	"github.com/dexon-foundation/dexon-consensus-core/common"
 	"github.com/dexon-foundation/dexon-consensus-core/core"
@@ -99,22 +98,11 @@ func (v *validator) run(serverEndpoint interface{}, legacy bool) {
 			break
 		}
 	}
+	v.consensus = core.NewConsensus(
+		v.app, v.gov, v.db, v.netModule, v.prvKey, v.sigToPub)
 	if legacy {
-		v.consensus = core.NewConsensus(
-			v.app, v.gov, v.db, v.netModule,
-			time.NewTicker(
-				time.Duration(
-					v.config.Legacy.ProposeIntervalMean)*time.Millisecond),
-			v.prvKey, v.sigToPub)
-
 		go v.consensus.RunLegacy()
 	} else {
-		v.consensus = core.NewConsensus(
-			v.app, v.gov, v.db, v.netModule,
-			time.NewTicker(
-				time.Duration(v.config.Lambda)*time.Millisecond),
-			v.prvKey, v.sigToPub)
-
 		go v.consensus.Run()
 	}