Add sequencer.stopped flag that can be used to start a node in sequencer mode...

Add sequencer.stopped flag that can be used to start a node in sequencer mode that doesn't produce blocks

op-node/flags/flags.go

@@ -94,6 +94,11 @@ var (
 		Usage:  "Enable sequencing of new L2 blocks. A separate batch submitter has to be deployed to publish the data for verifiers.",
 		EnvVar: prefixEnvVar("SEQUENCER_ENABLED"),
 	}
+	SequencerStoppedFlag = cli.BoolFlag{
+		Name:   "sequencer.stopped",
+		Usage:  "Initialize the sequencer in a stopped state. The sequencer can be started using the admin_startSequencer RPC",
+		EnvVar: prefixEnvVar("SEQUENCER_STOPPED"),
+	}
 	SequencerL1Confs = cli.Uint64Flag{
 		Name:     "sequencer.l1-confs",
 		Usage:    "Number of L1 blocks to keep distance from the L1 head as a sequencer for picking an L1 origin.",
@@ -197,6 +202,7 @@ var optionalFlags = append([]cli.Flag{
 	L2EngineJWTSecret,
 	VerifierL1Confs,
 	SequencerEnabledFlag,
+	SequencerStoppedFlag,
 	SequencerL1Confs,
 	L1EpochPollIntervalFlag,
 	LogLevelFlag,

op-node/rollup/driver/config.go

@@ -13,4 +13,7 @@ type Config struct {
 
 	// SequencerEnabled is true when the driver should sequence new blocks.
 	SequencerEnabled bool `json:"sequencer_enabled"`
+
+	// SequencerStopped is false when the driver should sequence new blocks.
+	SequencerStopped bool `json:"sequencer_stopped"`
 }

op-node/rollup/driver/state.go

@@ -284,7 +284,7 @@ func (s *Driver) eventLoop() {
 	for {
 		// If we are sequencing, update the trigger for the next sequencer action.
 		// This may adjust at any time based on fork-choice changes or previous errors.
-		if s.driverConfig.SequencerEnabled {
+		if s.driverConfig.SequencerEnabled && !s.driverConfig.SequencerStopped {
 			// update sequencer time if the head changed
 			if sequencingPlannedOnto != s.derivation.UnsafeL2Head().ID() {
 				planSequencerAction()
@@ -379,22 +379,22 @@ func (s *Driver) eventLoop() {
 			close(respCh)
 		case resp := <-s.startSequencer:
 			unsafeHead := s.derivation.UnsafeL2Head().Hash
-			if s.driverConfig.SequencerEnabled {
+			if !s.driverConfig.SequencerStopped {
 				resp.err <- errors.New("sequencer already running")
 			} else if !bytes.Equal(unsafeHead[:], resp.hash[:]) {
 				resp.err <- fmt.Errorf("block hash does not match: head %s, received %s", unsafeHead.String(), resp.hash.String())
 			} else {
 				s.log.Info("Sequencer has been started")
-				s.driverConfig.SequencerEnabled = true
+				s.driverConfig.SequencerStopped = false
 				sequencingPlannedOnto = eth.BlockID{}
 				close(resp.err)
 			}
 		case respCh := <-s.stopSequencer:
-			if !s.driverConfig.SequencerEnabled {
+			if s.driverConfig.SequencerStopped {
 				respCh <- hashAndError{err: errors.New("sequencer not running")}
 			} else {
 				s.log.Warn("Sequencer has been stopped")
-				s.driverConfig.SequencerEnabled = false
+				s.driverConfig.SequencerStopped = true
 				respCh <- hashAndError{hash: s.derivation.UnsafeL2Head().Hash}
 			}
 		case <-s.done:
@@ -422,6 +422,9 @@ func (s *Driver) ResetDerivationPipeline(ctx context.Context) error {
 }
 
 func (s *Driver) StartSequencer(ctx context.Context, blockHash common.Hash) error {
+	if !s.driverConfig.SequencerEnabled {
+		return errors.New("sequencer is not enabled")
+	}
 	h := hashAndErrorChannel{
 		hash: blockHash,
 		err:  make(chan error, 1),
@@ -440,6 +443,9 @@ func (s *Driver) StartSequencer(ctx context.Context, blockHash common.Hash) erro
 }
 
 func (s *Driver) StopSequencer(ctx context.Context) (common.Hash, error) {
+	if !s.driverConfig.SequencerEnabled {
+		return common.Hash{}, errors.New("sequencer is not enabled")
+	}
 	respCh := make(chan hashAndError, 1)
 	select {
 	case <-ctx.Done():

op-node/service.go

@@ -138,6 +138,7 @@ func NewDriverConfig(ctx *cli.Context) (*driver.Config, error) {
 		VerifierConfDepth:  ctx.GlobalUint64(flags.VerifierL1Confs.Name),
 		SequencerConfDepth: ctx.GlobalUint64(flags.SequencerL1Confs.Name),
 		SequencerEnabled:   ctx.GlobalBool(flags.SequencerEnabledFlag.Name),
+		SequencerStopped:   ctx.GlobalBool(flags.SequencerStoppedFlag.Name),
 	}, nil
 }