Add query-only mode flag

CHANGELOG.md

@@ -60,6 +60,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (ledger) [#1277](https://github.com/evmos/ethermint/pull/1277) Add Ledger preprocessing transaction hook for EIP-712-signed Cosmos payloads.
 * (rpc) [#1296](https://github.com/evmos/ethermint/pull/1296) Add RPC Backend unit tests.
 * (rpc) [#1352](https://github.com/evmos/ethermint/pull/1352) Make the grpc queries run concurrently, don't block the consensus state machine.
+* (cli) [#1360](https://github.com/evmos/ethermint/pull/1360) Introduce a new `query-only` flag, such that when enabled (grpc|jsonrpc|grpc,jsonrpc), will start the node in a query-only mode.
 
 ### Bug Fixes
 

server/flags/flags.go

@@ -18,6 +18,8 @@ const (
 	AppDBBackend = "app-db-backend"
 )
 
+const QueryOnly = "query-only"
+
 // GRPC-related flags.
 const (
 	GRPCEnable     = "grpc.enable"

server/start.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/codec"
 	"github.com/cosmos/cosmos-sdk/crypto/keyring"
+	"golang.org/x/exp/slices"
 
 	"github.com/spf13/cobra"
 
@@ -148,6 +149,8 @@ which accepts a path for the resulting pprof file.
 	cmd.Flags().Uint64(server.FlagMinRetainBlocks, 0, "Minimum block height offset during ABCI commit to prune Tendermint blocks")
 	cmd.Flags().String(srvflags.AppDBBackend, "", "The type of database for application and snapshots databases")
 
+	cmd.Flags().String(srvflags.QueryOnly, "", "Start the node in query only mode without Tendermint process (grpc|jsonrpc|grpc,jsonrpc)")
+
 	cmd.Flags().Bool(srvflags.GRPCEnable, true, "Define if the gRPC server should be enabled")
 	cmd.Flags().String(srvflags.GRPCAddress, serverconfig.DefaultGRPCAddress, "the gRPC server address to listen on")
 	cmd.Flags().Bool(srvflags.GRPCWebEnable, true, "Define if the gRPC-Web server should be enabled. (Note: gRPC must also be enabled.)")
@@ -156,7 +159,7 @@ which accepts a path for the resulting pprof file.
 	cmd.Flags().Bool(srvflags.RPCEnable, false, "Defines if Cosmos-sdk REST server should be enabled")
 	cmd.Flags().Bool(srvflags.EnabledUnsafeCors, false, "Defines if CORS should be enabled (unsafe - use it at your own risk)")
 
-	cmd.Flags().Bool(srvflags.JSONRPCEnable, true, "Define if the gRPC server should be enabled")
+	cmd.Flags().Bool(srvflags.JSONRPCEnable, true, "Define if the JSON-RPC server should be enabled")
 	cmd.Flags().StringSlice(srvflags.JSONRPCAPI, config.GetDefaultAPINamespaces(), "Defines a list of JSON-RPC namespaces that should be enabled")
 	cmd.Flags().String(srvflags.JSONRPCAddress, config.DefaultJSONRPCAddress, "the JSON-RPC server address to listen on")
 	cmd.Flags().String(srvflags.JSONWsAddress, config.DefaultJSONRPCWsAddress, "the JSON-RPC WS server address to listen on")
@@ -310,30 +313,46 @@ func startInProcess(ctx *server.Context, clientCtx client.Context, appCreator ty
 	}
 
 	genDocProvider := node.DefaultGenesisDocProviderFunc(cfg)
-	tmNode, err := node.NewNode(
-		cfg,
-		pvm.LoadOrGenFilePV(cfg.PrivValidatorKeyFile(), cfg.PrivValidatorStateFile()),
-		nodeKey,
-		proxy.NewLocalClientCreator(app),
-		genDocProvider,
-		node.DefaultDBProvider,
-		node.DefaultMetricsProvider(cfg.Instrumentation),
-		ctx.Logger.With("server", "node"),
+	var (
+		tmNode *node.Node
+		modes  = strings.Split(ctx.Viper.GetString(srvflags.QueryOnly), ",")
 	)
-	if err != nil {
-		logger.Error("failed init node", "error", err.Error())
-		return err
-	}
+	gRPCQueryMode := slices.Contains(modes, "grpc")
+	jsonRPCMode := slices.Contains(modes, "jsonrpc")
+	if gRPCQueryMode || jsonRPCMode {
+		ctx.Logger.Info(fmt.Sprintf("starting node in %s query only mode; Tendermint is disabled", modes))
+		if gRPCQueryMode {
+			config.GRPC.Enable = true
+		}
+		if jsonRPCMode {
+			config.JSONRPC.Enable = true
+		}
+	} else {
+		tmNode, err = node.NewNode(
+			cfg,
+			pvm.LoadOrGenFilePV(cfg.PrivValidatorKeyFile(), cfg.PrivValidatorStateFile()),
+			nodeKey,
+			proxy.NewLocalClientCreator(app),
+			genDocProvider,
+			node.DefaultDBProvider,
+			node.DefaultMetricsProvider(cfg.Instrumentation),
+			ctx.Logger.With("server", "node"),
+		)
+		if err != nil {
+			logger.Error("failed init node", "error", err.Error())
+			return err
+		}
 
-	if err := tmNode.Start(); err != nil {
-		logger.Error("failed start tendermint server", "error", err.Error())
-		return err
+		if err := tmNode.Start(); err != nil {
+			logger.Error("failed start tendermint server", "error", err.Error())
+			return err
+		}
 	}
 
 	// Add the tx service to the gRPC router. We only need to register this
 	// service if API or gRPC or JSONRPC is enabled, and avoid doing so in the general
 	// case, because it spawns a new local tendermint RPC client.
-	if config.API.Enable || config.GRPC.Enable || config.JSONRPC.Enable || config.JSONRPC.EnableIndexer {
+	if (config.API.Enable || config.GRPC.Enable || config.JSONRPC.Enable || config.JSONRPC.EnableIndexer) && tmNode != nil {
 		clientCtx = clientCtx.WithClient(local.New(tmNode))
 
 		app.RegisterTxService(clientCtx)
@@ -443,15 +462,62 @@ func startInProcess(ctx *server.Context, clientCtx client.Context, appCreator ty
 		if err != nil {
 			return err
 		}
+		defer grpcSrv.Stop()
 		if config.GRPCWeb.Enable {
 			grpcWebSrv, err = servergrpc.StartGRPCWeb(grpcSrv, config.Config)
 			if err != nil {
 				ctx.Logger.Error("failed to start grpc-web http server", "error", err)
 				return err
 			}
+			defer func() {
+				if err := grpcWebSrv.Close(); err != nil {
+					logger.Error("failed to close the grpcWebSrc", "error", err.Error())
+				}
+			}()
 		}
 	}
 
+	var (
+		httpSrv     *http.Server
+		httpSrvDone chan struct{}
+	)
+
+	if config.JSONRPC.Enable {
+		genDoc, err := genDocProvider()
+		if err != nil {
+			return err
+		}
+
+		clientCtx := clientCtx.WithChainID(genDoc.ChainID)
+
+		tmEndpoint := "/websocket"
+		tmRPCAddr := cfg.RPC.ListenAddress
+		httpSrv, httpSrvDone, err = StartJSONRPC(ctx, clientCtx, tmRPCAddr, tmEndpoint, &config, idxer)
+		if err != nil {
+			return err
+		}
+		defer func() {
+			shutdownCtx, cancelFn := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancelFn()
+			if err := httpSrv.Shutdown(shutdownCtx); err != nil {
+				logger.Error("HTTP server shutdown produced a warning", "error", err.Error())
+			} else {
+				logger.Info("HTTP server shut down, waiting 5 sec")
+				select {
+				case <-time.Tick(5 * time.Second):
+				case <-httpSrvDone:
+				}
+			}
+		}()
+	}
+
+	// At this point it is safe to block the process if we're in gRPC or JSON-RPC only mode as
+	// we do not need to start Rosetta or handle any Tendermint related processes.
+	if gRPCQueryMode || jsonRPCMode {
+		// wait for signal capture and gracefully return
+		return server.WaitForQuitSignals()
+	}
+
 	var rosettaSrv crgserver.Server
 	if config.Rosetta.Enable {
 		offlineMode := config.Rosetta.Offline
@@ -488,29 +554,8 @@ func startInProcess(ctx *server.Context, clientCtx client.Context, appCreator ty
 		}
 	}
 
-	var (
-		httpSrv     *http.Server
-		httpSrvDone chan struct{}
-	)
-
-	if config.JSONRPC.Enable {
-		genDoc, err := genDocProvider()
-		if err != nil {
-			return err
-		}
-
-		clientCtx := clientCtx.WithChainID(genDoc.ChainID)
-
-		tmEndpoint := "/websocket"
-		tmRPCAddr := cfg.RPC.ListenAddress
-		httpSrv, httpSrvDone, err = StartJSONRPC(ctx, clientCtx, tmRPCAddr, tmEndpoint, &config, idxer)
-		if err != nil {
-			return err
-		}
-	}
-
 	defer func() {
-		if tmNode.IsRunning() {
+		if tmNode != nil && tmNode.IsRunning() {
 			_ = tmNode.Stop()
 		}
 
@@ -521,31 +566,6 @@ func startInProcess(ctx *server.Context, clientCtx client.Context, appCreator ty
 		if apiSrv != nil {
 			_ = apiSrv.Close()
 		}
-
-		if grpcSrv != nil {
-			grpcSrv.Stop()
-			if grpcWebSrv != nil {
-				if err := grpcWebSrv.Close(); err != nil {
-					logger.Error("failed to close the grpcWebSrc", "error", err.Error())
-				}
-			}
-		}
-
-		if httpSrv != nil {
-			shutdownCtx, cancelFn := context.WithTimeout(context.Background(), 10*time.Second)
-			defer cancelFn()
-
-			if err := httpSrv.Shutdown(shutdownCtx); err != nil {
-				logger.Error("HTTP server shutdown produced a warning", "error", err.Error())
-			} else {
-				logger.Info("HTTP server shut down, waiting 5 sec")
-				select {
-				case <-time.Tick(5 * time.Second):
-				case <-httpSrvDone:
-				}
-			}
-		}
-
 		logger.Info("Bye!")
 	}()