feat(server): start grpc server and register services in standalone mode

CHANGELOG.md

@@ -40,6 +40,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Features
 
+* (server) [#18110](https://github.com/cosmos/cosmos-sdk/pull/18110) Start gRPC server in standalone mode
 * (tests) [#17868](https://github.com/cosmos/cosmos-sdk/pull/17868) Added helper method `SubmitTestTx` in testutil to broadcast test txns to test e2e tests.
 * (x/protocolpool) [#17657](https://github.com/cosmos/cosmos-sdk/pull/17657) Create a new `x/protocolpool` module that is responsible for handling community pool funds. This module is split out into a new module from x/distribution.
 * (baseapp) [#16581](https://github.com/cosmos/cosmos-sdk/pull/16581) Implement Optimistic Execution as an experimental feature (not enabled by default).

server/start.go

@@ -16,6 +16,7 @@ import (
 	"github.com/cometbft/cometbft/p2p"
 	pvm "github.com/cometbft/cometbft/privval"
 	"github.com/cometbft/cometbft/proxy"
+	rpchttp "github.com/cometbft/cometbft/rpc/client/http"
 	"github.com/cometbft/cometbft/rpc/client/local"
 	cmttypes "github.com/cometbft/cometbft/types"
 	dbm "github.com/cosmos/cosmos-db"
@@ -258,12 +259,12 @@ func start(svrCtx *Context, clientCtx client.Context, appCreator types.AppCreato
 	emitServerInfoMetrics()
 
 	if !withCmt {
-		return startStandAlone(svrCtx, app, opts)
+		return startStandAlone(svrCtx, svrCfg, clientCtx, app, opts)
 	}
 	return startInProcess(svrCtx, svrCfg, clientCtx, app, metrics, opts)
 }
 
-func startStandAlone(svrCtx *Context, app types.Application, opts StartCmdOptions) error {
+func startStandAlone(svrCtx *Context, svrCfg serverconfig.Config, clientCtx client.Context, app types.Application, opts StartCmdOptions) error {
 	addr := svrCtx.Viper.GetString(flagAddress)
 	transport := svrCtx.Viper.GetString(flagTransport)
 
@@ -277,6 +278,30 @@ func startStandAlone(svrCtx *Context, app types.Application, opts StartCmdOption
 
 	g, ctx := getCtx(svrCtx, false)
 
+	// Add the tx service to the gRPC router. We only need to register this
+	// service if gRPC is enabled.
+	if svrCfg.GRPC.Enable {
+		// create tendermint client
+		// assumes the rpc listen address is where tendermint has its rpc server
+		rpcclient, err := rpchttp.New(svrCtx.Config.RPC.ListenAddress, "/websocket")
+		if err != nil {
+			return err
+		}
+		// re-assign for making the client available below
+		// do not use := to avoid shadowing clientCtx
+		clientCtx = clientCtx.WithClient(rpcclient)
+
+		// use the provided clientCtx to register the services
+		app.RegisterTxService(clientCtx)
+		app.RegisterTendermintService(clientCtx)
+		app.RegisterNodeService(clientCtx, svrCfg)
+	}
+
+	_, _, err = startGrpcServer(ctx, g, svrCfg.GRPC, clientCtx, svrCtx, app)
+	if err != nil {
+		return err
+	}
+
 	g.Go(func() error {
 		if err := svr.Start(); err != nil {
 			svrCtx.Logger.Error("failed to start out-of-process ABCI server", "err", err)