op-challenger: Add cannon-snapshot-freq flag

op-challenger/cmd/main_test.go

@@ -214,6 +214,18 @@ func TestCannonL2(t *testing.T) {
 	})
 }
 
+func TestCannonSnapshotFreq(t *testing.T) {
+	t.Run("UsesDefault", func(t *testing.T) {
+		cfg := configForArgs(t, addRequiredArgs(config.TraceTypeCannon))
+		require.Equal(t, config.DefaultCannonSnapshotFreq, cfg.CannonSnapshotFreq)
+	})
+
+	t.Run("Valid", func(t *testing.T) {
+		cfg := configForArgs(t, addRequiredArgs(config.TraceTypeCannon, "--cannon-snapshot-freq=1234"))
+		require.Equal(t, uint(1234), cfg.CannonSnapshotFreq)
+	})
+}
+
 func verifyArgsInvalid(t *testing.T, messageContains string, cliArgs []string) {
 	_, _, err := runWithArgs(cliArgs)
 	require.ErrorContains(t, err, messageContains)

op-challenger/config/config.go

@@ -18,6 +18,7 @@ var (
 	ErrMissingAlphabetTrace          = errors.New("missing alphabet trace")
 	ErrMissingL1EthRPC               = errors.New("missing l1 eth rpc url")
 	ErrMissingGameAddress            = errors.New("missing game address")
+	ErrMissingCannonSnapshotFreq     = errors.New("missing cannon snapshot freq")
 )
 
 type TraceType string
@@ -51,6 +52,8 @@ func ValidTraceType(value TraceType) bool {
 	return false
 }
 
+const DefaultCannonSnapshotFreq = uint(10_000)
+
 // Config is a well typed config that is parsed from the CLI params.
 // This also contains config options for auxiliary services.
 // It is used to initialize the challenger.
@@ -71,6 +74,7 @@ type Config struct {
 	CannonAbsolutePreState string // File to load the absolute pre-state for Cannon traces from
 	CannonDatadir          string // Cannon Data Directory
 	CannonL2               string // L2 RPC Url
+	CannonSnapshotFreq     uint   // Frequency of snapshots to create when executing cannon (in VM instructions)
 
 	TxMgrConfig txmgr.CLIConfig
 }
@@ -92,6 +96,8 @@ func NewConfig(
 		TraceType: traceType,
 
 		TxMgrConfig: txmgr.NewCLIConfig(l1EthRpc),
+
+		CannonSnapshotFreq: DefaultCannonSnapshotFreq,
 	}
 }
 
@@ -121,6 +127,9 @@ func (c Config) Check() error {
 		if c.CannonL2 == "" {
 			return ErrMissingCannonL2
 		}
+		if c.CannonSnapshotFreq == 0 {
+			return ErrMissingCannonSnapshotFreq
+		}
 	}
 	if c.TraceType == TraceTypeAlphabet && c.AlphabetTrace == "" {
 		return ErrMissingAlphabetTrace

op-challenger/config/config_test.go

@@ -102,3 +102,11 @@ func TestCannonL2Required(t *testing.T) {
 	config.CannonL2 = ""
 	require.ErrorIs(t, config.Check(), ErrMissingCannonL2)
 }
+
+func TestCannonSnapshotFreq(t *testing.T) {
+	t.Run("MustNotBeZero", func(t *testing.T) {
+		cfg := validConfig(TraceTypeCannon)
+		cfg.CannonSnapshotFreq = 0
+		require.ErrorIs(t, cfg.Check(), ErrMissingCannonSnapshotFreq)
+	})
+}

op-challenger/flags/flags.go

@@ -83,6 +83,12 @@ var (
 		Usage:   "L2 Address of L2 JSON-RPC endpoint to use (eth and debug namespace required)  (cannon trace type only)",
 		EnvVars: prefixEnvVars("CANNON_L2"),
 	}
+	CannonSnapshotFreqFlag = &cli.UintFlag{
+		Name:    "cannon-snapshot-freq",
+		Usage:   "Frequency of cannon snapshots to generate in VM steps (cannon trace type only)",
+		EnvVars: prefixEnvVars("CANNON_SNAPSHOT_FREQ"),
+		Value:   config.DefaultCannonSnapshotFreq,
+	}
 )
 
 // requiredFlags are checked by [CheckRequired]
@@ -102,6 +108,7 @@ var optionalFlags = []cli.Flag{
 	CannonPreStateFlag,
 	CannonDatadirFlag,
 	CannonL2Flag,
+	CannonSnapshotFreqFlag,
 }
 
 func init() {
@@ -173,6 +180,7 @@ func NewConfigFromCLI(ctx *cli.Context) (*config.Config, error) {
 		CannonAbsolutePreState:  ctx.String(CannonPreStateFlag.Name),
 		CannonDatadir:           ctx.String(CannonDatadirFlag.Name),
 		CannonL2:                ctx.String(CannonL2Flag.Name),
+		CannonSnapshotFreq:      ctx.Uint(CannonSnapshotFreqFlag.Name),
 		AgreeWithProposedOutput: ctx.Bool(AgreeWithProposedOutputFlag.Name),
 		GameDepth:               ctx.Int(GameDepthFlag.Name),
 		TxMgrConfig:             txMgrConfig,