[Feature] Adding new flag which enables custom block time value (#384)

* block time configurable via block_time flag

* changed block time unit to milliseconds

* changed block headers timestamp to msec

* changed input flag default to 2000; changed description

* changed log output to milliseconds

* changed Prometheus metric for block time to milliseconds

* fix block_interval metric

* fix consensus_rounds metric to correspond to log output

* fix helper config merge BlockTime value

 * added comments to indicate milliseconds

* changed time.UnixMili to custom time functions for go backward compatibility

* set default block time as const

blockchain/blockchain.go

@@ -646,7 +646,7 @@ func (b *Blockchain) WriteBlock(block *types.Block) error {
 
 	if prevHeader, ok := b.GetHeaderByNumber(header.Number - 1); ok {
 		diff := header.Timestamp - prevHeader.Timestamp
-		logArgs = append(logArgs, "generation_time_in_sec", diff)
+		logArgs = append(logArgs, "generation_time_in_miliseconds", diff)
 	}
 
 	b.logger.Info("new block", logArgs...)

command/helper/config.go

@@ -35,6 +35,7 @@ type Config struct {
 	Join           string                 `json:"join_addr"`
 	Consensus      map[string]interface{} `json:"consensus"`
 	RestoreFile    string                 `json:"restore_file"`
+	BlockTime      uint64                 `json:"block_time_ms"` // block time im miliseconds
 }
 
 // Telemetry holds the config details for metric services.
@@ -59,6 +60,9 @@ type TxPool struct {
 	MaxSlots   uint64 `json:"max_slots"`
 }
 
+// variable defining default BlockTime parameter in miliseconds
+const defaultBlockTime uint64 = 2000
+
 // DefaultConfig returns the default server configuration
 func DefaultConfig() *Config {
 	return &Config{
@@ -80,6 +84,7 @@ func DefaultConfig() *Config {
 		Consensus:   map[string]interface{}{},
 		LogLevel:    "INFO",
 		RestoreFile: "",
+		BlockTime:   defaultBlockTime, // default block time in miliseconds
 	}
 }
 
@@ -177,6 +182,11 @@ func (c *Config) BuildConfig() (*server.Config, error) {
 		conf.RestoreFile = &c.RestoreFile
 	}
 
+	// set block time if not default
+	if c.BlockTime != defaultBlockTime {
+		conf.BlockTime = c.BlockTime
+	}
+
 	// if we are in dev mode, change the consensus protocol with 'dev'
 	// and disable discovery of other nodes
 	// TODO: Disable networking altogether.
@@ -311,6 +321,11 @@ func (c *Config) mergeConfigWith(otherConfig *Config) error {
 		c.RestoreFile = otherConfig.RestoreFile
 	}
 
+	// if block time not default, set to new value
+	if otherConfig.BlockTime != defaultBlockTime {
+		c.BlockTime = otherConfig.BlockTime
+	}
+
 	if err := mergo.Merge(&c.Consensus, otherConfig.Consensus, mergo.WithOverride); err != nil {
 		return err
 	}

command/helper/helper.go

@@ -472,6 +472,7 @@ func ReadConfig(baseCommand string, args []string) (*Config, error) {
 	flags.StringVar(&cliConfig.BlockGasTarget, "block-gas-target", strconv.FormatUint(0, 10), "")
 	flags.StringVar(&cliConfig.Secrets, "secrets-config", "", "")
 	flags.StringVar(&cliConfig.RestoreFile, "restore", "", "")
+	flags.Uint64Var(&cliConfig.BlockTime, "block-time", config.BlockTime, "")
 
 	if err := flags.Parse(args); err != nil {
 		return nil, err

command/server/server_command.go

@@ -230,6 +230,14 @@ func (c *ServerCommand) DefineFlags() {
 		},
 		FlagOptional: true,
 	}
+
+	c.FlagMap["block-time"] = helper.FlagDescriptor{
+		Description: fmt.Sprintf("Sets block time in miliseconds. Default: %d", helper.DefaultConfig().BlockTime),
+		Arguments: []string{
+			"BLOCK_TIME",
+		},
+		FlagOptional: true,
+	}
 }
 
 // GetHelperText returns a simple description of the command

consensus/consensus.go

@@ -65,6 +65,7 @@ type ConsensusParams struct {
 	Logger         hclog.Logger
 	Metrics        *Metrics
 	SecretsManager secrets.SecretsManager
+	BlockTime      uint64 // block time im miliseconds
 }
 
 // Factory is the factory function to create a discovery backend

consensus/ibft/ibft.go

@@ -96,6 +96,8 @@ type Ibft struct {
 	secretsManager secrets.SecretsManager
 
 	mechanism ConsensusMechanism // IBFT ConsensusMechanism used (PoA / PoS)
+
+	blockTime uint64 // Configurable consensus blocktime in miliseconds
 }
 
 // Define the type of the IBFT consensus
@@ -245,6 +247,7 @@ func Factory(
 		sealing:        params.Seal,
 		metrics:        params.Metrics,
 		secretsManager: params.SecretsManager,
+		blockTime:      params.BlockTime,
 	}
 
 	// Initialize the mechanism
@@ -576,8 +579,6 @@ func (i *Ibft) runSyncState() {
 	}
 }
 
-var defaultBlockPeriod = 2 * time.Second
-
 // buildBlock builds the block, based on the passed in snapshot and parent header
 func (i *Ibft) buildBlock(snap *Snapshot, parent *types.Header) (*types.Block, error) {
 	header := &types.Header{
@@ -608,15 +609,18 @@ func (i *Ibft) buildBlock(snap *Snapshot, parent *types.Header) (*types.Block, e
 		i.logger.Error(fmt.Sprintf("Unable to run hook %s, %v", CandidateVoteHook, hookErr))
 	}
 
+	// calculate millisecond values from consensus custom functions in utils.go file
+	// to preserve go backward compatibility as time.UnixMili is available as of go 17
+
 	// set the timestamp
-	parentTime := time.Unix(int64(parent.Timestamp), 0)
-	headerTime := parentTime.Add(defaultBlockPeriod)
+	parentTime := consensus.MilliToUnix(parent.Timestamp)
+	headerTime := parentTime.Add(time.Duration(i.blockTime) * time.Millisecond)
 
 	if headerTime.Before(time.Now()) {
 		headerTime = time.Now()
 	}
 
-	header.Timestamp = uint64(headerTime.Unix())
+	header.Timestamp = consensus.UnixToMilli(headerTime)
 
 	// we need to include in the extra field the current set of validators
 	putIbftExtraValidators(header, snap.Set)
@@ -732,8 +736,11 @@ func (i *Ibft) writeTransactions(gasLimit uint64, transition transitionInterface
 // If it turns out that the current node is the proposer, it builds a block,
 // and sends preprepare and then prepare messages.
 func (i *Ibft) runAcceptState() { // start new round
+	// set log output
 	logger := i.logger.Named("acceptState")
 	logger.Info("Accept state", "sequence", i.state.view.Sequence, "round", i.state.view.Round+1)
+	// set consensus_rounds metric output
+	i.metrics.Rounds.Set(float64(i.state.view.Round + 1))
 
 	// This is the state in which we either propose a block or wait for the pre-prepare message
 	parent := i.blockchain.Header()
@@ -798,7 +805,7 @@ func (i *Ibft) runAcceptState() { // start new round
 			}
 
 			// calculate how much time do we have to wait to mine the block
-			delay := time.Until(time.Unix(int64(i.state.block.Header.Timestamp), 0))
+			delay := time.Until(consensus.MilliToUnix(i.state.block.Header.Timestamp))
 
 			select {
 			case <-time.After(delay):
@@ -970,15 +977,15 @@ func (i *Ibft) runValidateState() {
 // updateMetrics will update various metrics based on the given block
 // currently we capture No.of Txs and block interval metrics using this function
 func (i *Ibft) updateMetrics(block *types.Block) {
+	// get previous header
 	prvHeader, _ := i.blockchain.GetHeaderByNumber(block.Number() - 1)
-	parentTime := time.Unix(int64(prvHeader.Timestamp), 0)
-	headerTime := time.Unix(int64(block.Header.Timestamp), 0)
-	//Update the block interval metric
-	if block.Number() > 1 {
-		i.metrics.BlockInterval.Observe(
-			headerTime.Sub(parentTime).Seconds(),
-		)
-	}
+	// calculate difference between previous and current header timestamps
+	// diff := time.Unix(int64(block.Header.Timestamp),0).Sub(time.Unix(int64(prvHeader.Timestamp),0))
+	diff := consensus.MilliToUnix(block.Header.Timestamp).Sub(consensus.MilliToUnix(prvHeader.Timestamp))
+
+	// update block_interval metric
+	i.metrics.BlockInterval.Set(float64(diff.Milliseconds()))
+
 	//Update the Number of transactions in the block metric
 	i.metrics.NumTxs.Set(float64(len(block.Body().Transactions)))
 }

consensus/metrics.go

@@ -17,7 +17,7 @@ type Metrics struct {
 	NumTxs metrics.Gauge
 
 	//Time between current block and the previous block in seconds
-	BlockInterval metrics.Histogram
+	BlockInterval metrics.Gauge
 }
 
 // GetPrometheusMetrics return the consensus metrics instance
@@ -48,11 +48,11 @@ func GetPrometheusMetrics(namespace string, labelsWithValues ...string) *Metrics
 			Help:      "Number of transactions.",
 		}, labels).With(labelsWithValues...),
 
-		BlockInterval: prometheus.NewHistogramFrom(stdprometheus.HistogramOpts{
+		BlockInterval: prometheus.NewGaugeFrom(stdprometheus.GaugeOpts{
 			Namespace: namespace,
 			Subsystem: "consensus",
 			Name:      "block_interval",
-			Help:      "Time between current block and the previous block in seconds.",
+			Help:      "Time between current block and the previous block in miliseconds.",
 		}, labels).With(labelsWithValues...),
 	}
 }
@@ -63,6 +63,6 @@ func NilMetrics() *Metrics {
 		Validators:    discard.NewGauge(),
 		Rounds:        discard.NewGauge(),
 		NumTxs:        discard.NewGauge(),
-		BlockInterval: discard.NewHistogram(),
+		BlockInterval: discard.NewGauge(),
 	}
 }

consensus/utils.go

@@ -1,6 +1,8 @@
 package consensus
 
 import (
+	"time"
+
 	"github.com/0xPolygon/polygon-edge/types"
 	"github.com/0xPolygon/polygon-edge/types/buildroot"
 )
@@ -38,3 +40,13 @@ func BuildBlock(params BuildBlockParams) *types.Block {
 		Transactions: txs,
 	}
 }
+
+// MilliToUnix returns the local Time corresponding to the given Unix time m milliseconds since January 1, 1970 UTC.
+func MilliToUnix(m uint64) time.Time {
+	return time.Unix(0, int64(m)*1e6)
+}
+
+// UnixToMilli returns uint64 value for miliseconds
+func UnixToMilli(t time.Time) uint64 {
+	return uint64(t.UnixNano() / 1e6)
+}

server/config.go

@@ -10,6 +10,7 @@ import (
 
 const DefaultGRPCPort int = 9632
 const DefaultJSONRPCPort int = 8545
+const DefaultBlockTime = 2000 // in milliseconds
 
 // Config is used to parametrize the minimal client
 type Config struct {
@@ -26,6 +27,7 @@ type Config struct {
 	MaxSlots       uint64
 	SecretsManager *secrets.SecretsManagerConfig
 	RestoreFile    *string
+	BlockTime      uint64
 }
 
 // DefaultConfig returns the default config for JSON-RPC, GRPC (ports) and Networking
@@ -36,6 +38,7 @@ func DefaultConfig() *Config {
 		Network:        network.DefaultConfig(),
 		Telemetry:      &Telemetry{PrometheusAddr: nil},
 		SecretsManager: nil,
+		BlockTime:      DefaultBlockTime, // default block time in milliseconds
 	}
 }
 

server/server.go

@@ -362,6 +362,7 @@ func (s *Server) setupConsensus() error {
 			Logger:         s.logger.Named("consensus"),
 			Metrics:        s.serverMetrics.consensus,
 			SecretsManager: s.secretsManager,
+			BlockTime:      s.config.BlockTime,
 		},
 	)