feat: add Close method for resource cleanup in graceful shutdown (backport #16193)

CHANGELOG.md

@@ -45,6 +45,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (gov) [#15979](https://github.com/cosmos/cosmos-sdk/pull/15979) Improve gov error message when failing to convert v1 proposal to v1beta1.
 * (server) [#16061](https://github.com/cosmos/cosmos-sdk/pull/16061) add comet bootstrap command
 * (store) [#16067](https://github.com/cosmos/cosmos-sdk/pull/16067) Add local snapshots management commands.
+* (baseapp) [#16193](https://github.com/cosmos/cosmos-sdk/pull/16193) Add `Close` method to `BaseApp` for custom app to cleanup resource in graceful shutdown.
 
 ### Bug Fixes
 

baseapp/baseapp.go

@@ -844,3 +844,8 @@ func (app *BaseApp) runMsgs(ctx sdk.Context, msgs []sdk.Msg, mode runTxMode) (*s
 func makeABCIData(msgResponses []*codectypes.Any) ([]byte, error) {
 	return proto.Marshal(&sdk.TxMsgData{MsgResponses: msgResponses})
 }
+
+// Close is called in start cmd to gracefully cleanup resources.
+func (app *BaseApp) Close() error {
+	return nil
+}

server/start.go

@@ -244,6 +244,10 @@ func startStandAlone(ctx *Context, appCreator types.AppCreator) error {
 		if err = svr.Stop(); err != nil {
 			tmos.Exit(err.Error())
 		}
+
+		if err = app.Close(); err != nil {
+			tmos.Exit(err.Error())
+		}
 	}()
 
 	// Wait for SIGINT or SIGTERM signal
@@ -485,6 +489,7 @@ func startInProcess(ctx *Context, clientCtx client.Context, appCreator types.App
 	defer func() {
 		if tmNode != nil && tmNode.IsRunning() {
 			_ = tmNode.Stop()
+			_ = app.Close()
 		}
 
 		if apiSrv != nil {

server/types/app.go

@@ -59,6 +59,9 @@ type (
 
 		// Return the snapshot manager
 		SnapshotManager() *snapshots.Manager
+
+		// Close is called in start cmd to gracefully cleanup resources.
+		Close() error
 	}
 
 	// ApplicationQueryService defines an extension of the Application interface