feat(op-challenger): Parallelize Agent Actions (#9804)

* feat(op-challenger): Place agent actions behind a synced wait group

* op-challenger: Split out individual action into a separate method to reduce nesting.

---------
Co-authored-by: Adrian Sutton <adrian@oplabs.co>

op-challenger/game/fault/agent.go

@@ -67,49 +67,56 @@ func (a *Agent) Act(ctx context.Context) error {
 	if a.tryResolve(ctx) {
 		return nil
 	}
+
 	game, err := a.newGameFromContracts(ctx)
 	if err != nil {
 		return fmt.Errorf("create game from contracts: %w", err)
 	}
 
-	// Calculate the actions to take
 	actions, err := a.solver.CalculateNextActions(ctx, game)
 	if err != nil {
 		a.log.Error("Failed to calculate all required moves", "err", err)
 	}
 
-	// Perform the actions
+	var wg sync.WaitGroup
+	wg.Add(len(actions))
 	for _, action := range actions {
-		actionLog := a.log.New("action", action.Type, "is_attack", action.IsAttack, "parent", action.ParentIdx)
-		if action.Type == types.ActionTypeStep {
-			containsOracleData := action.OracleData != nil
-			isLocal := containsOracleData && action.OracleData.IsLocal
-			actionLog = actionLog.New(
-				"prestate", common.Bytes2Hex(action.PreState),
-				"proof", common.Bytes2Hex(action.ProofData),
-				"containsOracleData", containsOracleData,
-				"isLocalPreimage", isLocal,
-			)
-			if action.OracleData != nil {
-				actionLog = actionLog.New("oracleKey", common.Bytes2Hex(action.OracleData.OracleKey))
-			}
-		} else {
-			actionLog = actionLog.New("value", action.Value)
-		}
+		go a.performAction(ctx, &wg, action)
+	}
+	wg.Wait()
+	return nil
+}
 
-		switch action.Type {
-		case types.ActionTypeMove:
-			a.metrics.RecordGameMove()
-		case types.ActionTypeStep:
-			a.metrics.RecordGameStep()
-		}
-		actionLog.Info("Performing action")
-		err := a.responder.PerformAction(ctx, action)
-		if err != nil {
-			actionLog.Error("Action failed", "err", err)
+func (a *Agent) performAction(ctx context.Context, wg *sync.WaitGroup, action types.Action) {
+	defer wg.Done()
+	actionLog := a.log.New("action", action.Type, "is_attack", action.IsAttack, "parent", action.ParentIdx)
+	if action.Type == types.ActionTypeStep {
+		containsOracleData := action.OracleData != nil
+		isLocal := containsOracleData && action.OracleData.IsLocal
+		actionLog = actionLog.New(
+			"prestate", common.Bytes2Hex(action.PreState),
+			"proof", common.Bytes2Hex(action.ProofData),
+			"containsOracleData", containsOracleData,
+			"isLocalPreimage", isLocal,
+		)
+		if action.OracleData != nil {
+			actionLog = actionLog.New("oracleKey", common.Bytes2Hex(action.OracleData.OracleKey))
 		}
+	} else {
+		actionLog = actionLog.New("value", action.Value)
+	}
+
+	switch action.Type {
+	case types.ActionTypeMove:
+		a.metrics.RecordGameMove()
+	case types.ActionTypeStep:
+		a.metrics.RecordGameStep()
+	}
+	actionLog.Info("Performing action")
+	err := a.responder.PerformAction(ctx, action)
+	if err != nil {
+		actionLog.Error("Action failed", "err", err)
 	}
-	return nil
 }
 
 // tryResolve resolves the game if it is in a winning state