feat: make validator key injectable by application developers (backport #21608) (#21802)

Co-authored-by: Marko <marko@baricevic.me>
Co-authored-by: marbar3778 <marbar3778@yahoo.com>

server/start.go

@@ -374,9 +374,7 @@ func startCmtNode(
 		return nil, cleanupFn, err
 	}
 
-	pv, err := pvm.LoadOrGenFilePV(cfg.PrivValidatorKeyFile(), cfg.PrivValidatorStateFile(), func() (cmtcrypto.PrivKey, error) {
-		return cmted25519.GenPrivKey(), nil
-	}) // TODO:  make this modular
+	pv, err := pvm.LoadOrGenFilePV(cfg.PrivValidatorKeyFile(), cfg.PrivValidatorStateFile(), app.ValidatorKeyProvider())
 	if err != nil {
 		return nil, cleanupFn, err
 	}

server/types/app.go

@@ -5,6 +5,7 @@ import (
 	"io"
 
 	cmtproto "github.com/cometbft/cometbft/api/cometbft/types/v1"
+	cmtcrypto "github.com/cometbft/cometbft/crypto"
 	cmttypes "github.com/cometbft/cometbft/types"
 	"github.com/cosmos/gogoproto/grpc"
 
@@ -57,6 +58,9 @@ type (
 		// SnapshotManager return the snapshot manager
 		SnapshotManager() *snapshots.Manager
 
+		// ValidatorKeyProvider returns a function that generates a validator key
+		ValidatorKeyProvider() func() (cmtcrypto.PrivKey, error)
+
 		// Close is called in start cmd to gracefully cleanup resources.
 		// Must be safe to be called multiple times.
 		Close() error

server/v2/cometbft/options.go

@@ -1,6 +1,9 @@
 package cometbft
 
 import (
+	cmtcrypto "github.com/cometbft/cometbft/crypto"
+	cmted22519 "github.com/cometbft/cometbft/crypto/ed25519"
+
 	"cosmossdk.io/core/transaction"
 	"cosmossdk.io/server/v2/cometbft/handlers"
 	"cosmossdk.io/server/v2/cometbft/mempool"
@@ -8,6 +11,8 @@ import (
 	"cosmossdk.io/store/v2/snapshots"
 )
 
+type keyGenF = func() (cmtcrypto.PrivKey, error)
+
 // ServerOptions defines the options for the CometBFT server.
 // When an option takes a map[string]any, it can access the app.tom's cometbft section and the config.toml config.
 type ServerOptions[T transaction.Tx] struct {
@@ -15,6 +20,7 @@ type ServerOptions[T transaction.Tx] struct {
 	ProcessProposalHandler     handlers.ProcessHandler[T]
 	VerifyVoteExtensionHandler handlers.VerifyVoteExtensionhandler
 	ExtendVoteHandler          handlers.ExtendVoteHandler
+	KeygenF                    keyGenF
 
 	Mempool         func(cfg map[string]any) mempool.Mempool[T]
 	SnapshotOptions func(cfg map[string]any) snapshots.SnapshotOptions
@@ -35,5 +41,6 @@ func DefaultServerOptions[T transaction.Tx]() ServerOptions[T] {
 		SnapshotOptions:            func(cfg map[string]any) snapshots.SnapshotOptions { return snapshots.NewSnapshotOptions(0, 0) },
 		AddrPeerFilter:             nil,
 		IdPeerFilter:               nil,
+		KeygenF:                    func() (cmtcrypto.PrivKey, error) { return cmted22519.GenPrivKey(), nil },
 	}
 }

server/v2/cometbft/server.go

@@ -11,8 +11,6 @@ import (
 	abciserver "github.com/cometbft/cometbft/abci/server"
 	cmtcmd "github.com/cometbft/cometbft/cmd/cometbft/commands"
 	cmtcfg "github.com/cometbft/cometbft/config"
-	cmtcrypto "github.com/cometbft/cometbft/crypto"
-	cmted25519 "github.com/cometbft/cometbft/crypto/ed25519"
 	"github.com/cometbft/cometbft/node"
 	"github.com/cometbft/cometbft/p2p"
 	pvm "github.com/cometbft/cometbft/privval"
@@ -159,9 +157,7 @@ func (s *CometBFTServer[T]) Start(ctx context.Context) error {
 	pv, err := pvm.LoadOrGenFilePV(
 		s.config.ConfigTomlConfig.PrivValidatorKeyFile(),
 		s.config.ConfigTomlConfig.PrivValidatorStateFile(),
-		func() (cmtcrypto.PrivKey, error) {
-			return cmted25519.GenPrivKey(), nil
-		},
+		s.serverOptions.KeygenF,
 	)
 	if err != nil {
 		return err