feat(server/v2/cometbft): add checktx handler (backport #21985) (#22094)

Co-authored-by: Marko <[email protected]>

server/v2/cometbft/abci.go

@@ -64,6 +64,7 @@ type Consensus[T transaction.Tx] struct {
 	processProposalHandler handlers.ProcessHandler[T]
 	verifyVoteExt          handlers.VerifyVoteExtensionhandler
 	extendVote             handlers.ExtendVoteHandler
+	checkTxHandler         handlers.CheckTxHandler[T]
 
 	addrPeerFilter types.PeerFilter // filter peers by address and port
 	idPeerFilter   types.PeerFilter // filter peers by node ID
@@ -136,31 +137,35 @@ func (c *Consensus[T]) CheckTx(ctx context.Context, req *abciproto.CheckTxReques
 		return nil, err
 	}
 
-	resp, err := c.app.ValidateTx(ctx, decodedTx)
-	// we do not want to return a cometbft error, but a check tx response with the error
-	if err != nil && !errors.Is(err, resp.Error) {
-		return nil, err
-	}
+	if c.checkTxHandler == nil {
+		resp, err := c.app.ValidateTx(ctx, decodedTx)
+		// we do not want to return a cometbft error, but a check tx response with the error
+		if err != nil && !errors.Is(err, resp.Error) {
+			return nil, err
+		}
 
-	events, err := intoABCIEvents(resp.Events, c.indexedEvents)
-	if err != nil {
-		return nil, err
-	}
+		events, err := intoABCIEvents(resp.Events, c.indexedEvents)
+		if err != nil {
+			return nil, err
+		}
 
-	cometResp := &abciproto.CheckTxResponse{
-		Code:      0,
-		GasWanted: uint64ToInt64(resp.GasWanted),
-		GasUsed:   uint64ToInt64(resp.GasUsed),
-		Events:    events,
-	}
-	if resp.Error != nil {
-		space, code, log := errorsmod.ABCIInfo(resp.Error, c.cfg.AppTomlConfig.Trace)
-		cometResp.Code = code
-		cometResp.Codespace = space
-		cometResp.Log = log
+		cometResp := &abciproto.CheckTxResponse{
+			Code:      0,
+			GasWanted: uint64ToInt64(resp.GasWanted),
+			GasUsed:   uint64ToInt64(resp.GasUsed),
+			Events:    events,
+		}
+		if resp.Error != nil {
+			space, code, log := errorsmod.ABCIInfo(resp.Error, c.cfg.AppTomlConfig.Trace)
+			cometResp.Code = code
+			cometResp.Codespace = space
+			cometResp.Log = log
+		}
+
+		return cometResp, nil
 	}
 
-	return cometResp, nil
+	return c.checkTxHandler(c.app.ValidateTx)
 }
 
 // Info implements types.Application.

server/v2/cometbft/handlers/handlers.go

@@ -5,6 +5,7 @@ import (
 
 	abci "github.com/cometbft/cometbft/api/cometbft/abci/v1"
 
+	"cosmossdk.io/core/server"
 	"cosmossdk.io/core/store"
 	"cosmossdk.io/core/transaction"
 )
@@ -27,4 +28,7 @@ type (
 	// It takes a context, a store reader map, and a request to extend a vote.
 	// It returns a response to extend the vote and an error if any.
 	ExtendVoteHandler func(context.Context, store.ReaderMap, *abci.ExtendVoteRequest) (*abci.ExtendVoteResponse, error)
+
+	// CheckTxHandler is a function type that handles the execution of a transaction.
+	CheckTxHandler[T transaction.Tx] func(func(ctx context.Context, tx T) (server.TxResult, error)) (*abci.CheckTxResponse, error)
 )

server/v2/cometbft/options.go

@@ -18,6 +18,7 @@ type keyGenF = func() (cmtcrypto.PrivKey, error)
 type ServerOptions[T transaction.Tx] struct {
 	PrepareProposalHandler     handlers.PrepareHandler[T]
 	ProcessProposalHandler     handlers.ProcessHandler[T]
+	CheckTxHandler             handlers.CheckTxHandler[T]
 	VerifyVoteExtensionHandler handlers.VerifyVoteExtensionhandler
 	ExtendVoteHandler          handlers.ExtendVoteHandler
 	KeygenF                    keyGenF
@@ -35,6 +36,7 @@ func DefaultServerOptions[T transaction.Tx]() ServerOptions[T] {
 	return ServerOptions[T]{
 		PrepareProposalHandler:     handlers.NoOpPrepareProposal[T](),
 		ProcessProposalHandler:     handlers.NoOpProcessProposal[T](),
+		CheckTxHandler:             nil,
 		VerifyVoteExtensionHandler: handlers.NoOpVerifyVoteExtensionHandler(),
 		ExtendVoteHandler:          handlers.NoOpExtendVote(),
 		Mempool:                    func(cfg map[string]any) mempool.Mempool[T] { return mempool.NoOpMempool[T]{} },

server/v2/cometbft/server.go

@@ -113,6 +113,7 @@ func (s *CometBFTServer[T]) Init(appI serverv2.AppI[T], cfg map[string]any, logg
 	)
 	consensus.prepareProposalHandler = s.serverOptions.PrepareProposalHandler
 	consensus.processProposalHandler = s.serverOptions.ProcessProposalHandler
+	consensus.checkTxHandler = s.serverOptions.CheckTxHandler
 	consensus.verifyVoteExt = s.serverOptions.VerifyVoteExtensionHandler
 	consensus.extendVote = s.serverOptions.ExtendVoteHandler
 	consensus.addrPeerFilter = s.serverOptions.AddrPeerFilter