Refactors the challenger programmatic entrypoint logic into a fault

'service' for tighter package management.

op-challenger/challenger.go

@@ -4,46 +4,17 @@ import (
 	"context"
 	"fmt"
 
-	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
 	"github.com/ethereum-optimism/optimism/op-challenger/config"
 	"github.com/ethereum-optimism/optimism/op-challenger/fault"
-	"github.com/ethereum-optimism/optimism/op-service/txmgr"
-	"github.com/ethereum-optimism/optimism/op-service/txmgr/metrics"
-	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/log"
 )
 
 // Main is the programmatic entry-point for running op-challenger
 func Main(ctx context.Context, logger log.Logger, cfg *config.Config) error {
-	client, err := ethclient.Dial(cfg.L1EthRpc)
+	service, err := fault.NewService(ctx, logger, cfg)
 	if err != nil {
-		return fmt.Errorf("failed to dial L1: %w", err)
+		return fmt.Errorf("failed to create the fault service: %w", err)
 	}
 
-	txMgr, err := txmgr.NewSimpleTxManager("challenger", logger, &metrics.NoopTxMetrics{}, cfg.TxMgrConfig)
-	if err != nil {
-		return fmt.Errorf("failed to create the transaction manager: %w", err)
-	}
-
-	contract, err := bindings.NewFaultDisputeGameCaller(cfg.GameAddress, client)
-	if err != nil {
-		return fmt.Errorf("failed to bind the fault dispute game contract: %w", err)
-	}
-
-	gameLogger := logger.New("game", cfg.GameAddress)
-	loader := fault.NewLoader(contract)
-	responder, err := fault.NewFaultResponder(gameLogger, txMgr, cfg.GameAddress)
-	if err != nil {
-		return fmt.Errorf("failed to create the responder: %w", err)
-	}
-	trace := fault.NewAlphabetProvider(cfg.AlphabetTrace, uint64(cfg.GameDepth))
-
-	agent := fault.NewAgent(loader, cfg.GameDepth, trace, responder, cfg.AgreeWithProposedOutput, gameLogger)
-
-	caller, err := fault.NewFaultCallerFromBindings(cfg.GameAddress, client, gameLogger)
-	if err != nil {
-		return fmt.Errorf("failed to bind the fault contract: %w", err)
-	}
-
-	return fault.MonitorGame(ctx, gameLogger, cfg.AgreeWithProposedOutput, agent, caller)
+	return service.MonitorGame(ctx)
 }

op-challenger/fault/service.go

+package fault
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/ethereum-optimism/optimism/op-bindings/bindings"
+	"github.com/ethereum-optimism/optimism/op-challenger/config"
+	"github.com/ethereum-optimism/optimism/op-service/txmgr"
+	"github.com/ethereum-optimism/optimism/op-service/txmgr/metrics"
+	"github.com/ethereum/go-ethereum/ethclient"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// Service provides a clean interface for the challenger to interact
+// with the fault package.
+type Service interface {
+	// MonitorGame monitors the fault dispute game and attempts to progress it.
+	MonitorGame(context.Context) error
+}
+
+type service struct {
+	agent                   *Agent
+	agreeWithProposedOutput bool
+	caller                  *FaultCaller
+	logger                  log.Logger
+}
+
+// NewService creates a new Service.
+func NewService(ctx context.Context, logger log.Logger, cfg *config.Config) (*service, error) {
+	client, err := ethclient.Dial(cfg.L1EthRpc)
+	if err != nil {
+		return nil, fmt.Errorf("failed to dial L1: %w", err)
+	}
+
+	txMgr, err := txmgr.NewSimpleTxManager("challenger", logger, &metrics.NoopTxMetrics{}, cfg.TxMgrConfig)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create the transaction manager: %w", err)
+	}
+
+	contract, err := bindings.NewFaultDisputeGameCaller(cfg.GameAddress, client)
+	if err != nil {
+		return nil, fmt.Errorf("failed to bind the fault dispute game contract: %w", err)
+	}
+
+	loader := NewLoader(contract)
+	gameLogger := logger.New("game", cfg.GameAddress)
+	responder, err := NewFaultResponder(gameLogger, txMgr, cfg.GameAddress)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create the responder: %w", err)
+	}
+
+	trace := NewAlphabetProvider(cfg.AlphabetTrace, uint64(cfg.GameDepth))
+
+	agent := NewAgent(loader, cfg.GameDepth, trace, responder, cfg.AgreeWithProposedOutput, gameLogger)
+
+	caller, err := NewFaultCallerFromBindings(cfg.GameAddress, client, gameLogger)
+	if err != nil {
+		return nil, fmt.Errorf("failed to bind the fault contract: %w", err)
+	}
+
+	return &service{
+		agent:                   agent,
+		agreeWithProposedOutput: cfg.AgreeWithProposedOutput,
+		caller:                  caller,
+		logger:                  gameLogger,
+	}, nil
+}
+
+// MonitorGame monitors the fault dispute game and attempts to progress it.
+func (s *service) MonitorGame(ctx context.Context) error {
+	return MonitorGame(ctx, s.logger, s.agreeWithProposedOutput, s.agent, s.caller)
+}