imp(rpc,server): concurrent gRPC queries (#1352)

* Problem: grpc query is not run concurrently

Solution:
- Initiate the GRPCClient introduced in [sdk 0.46](https://github.com/cosmos/cosmos-sdk/pull/11234).

* Update CHANGELOG.md

* Update CHANGELOG.md

* Update server/start.go

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

* wrap error

* Update server/start.go

* more complete copy

* fix grpc crash

Co-authored-by: Federico Kunze Küllmer <31522760+fedekunze@users.noreply.github.com>

CHANGELOG.md

@@ -59,6 +59,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (test) [#1311](https://github.com/evmos/ethermint/pull/1311) Add integration test for the `rollback` cmd
 * (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.
 
 ### Bug Fixes
 

server/start.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"net"
 	"net/http"
 	"os"
 	"path/filepath"
@@ -17,6 +18,7 @@ import (
 	"github.com/spf13/cobra"
 
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
 
 	abciserver "github.com/tendermint/tendermint/abci/server"
 	tcmd "github.com/tendermint/tendermint/cmd/tendermint/commands"
@@ -39,6 +41,7 @@ import (
 	serverconfig "github.com/cosmos/cosmos-sdk/server/config"
 	servergrpc "github.com/cosmos/cosmos-sdk/server/grpc"
 	"github.com/cosmos/cosmos-sdk/server/types"
+	sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
 
 	"github.com/evmos/ethermint/indexer"
 	ethdebug "github.com/evmos/ethermint/rpc/namespaces/ethereum/debug"
@@ -363,17 +366,57 @@ func startInProcess(ctx *server.Context, clientCtx client.Context, appCreator ty
 		}
 	}
 
-	var apiSrv *api.Server
+	if config.API.Enable || config.JSONRPC.Enable {
-	if config.API.Enable {
 		genDoc, err := genDocProvider()
 		if err != nil {
 			return err
 		}
 
-		clientCtx := clientCtx.
+		clientCtx = clientCtx.
 			WithHomeDir(home).
 			WithChainID(genDoc.ChainID)
 
+		// Set `GRPCClient` to `clientCtx` to enjoy concurrent grpc query.
+		// only use it if gRPC server is enabled.
+		if config.GRPC.Enable {
+			_, port, err := net.SplitHostPort(config.GRPC.Address)
+			if err != nil {
+				return sdkerrors.Wrapf(err, "invalid grpc address %s", config.GRPC.Address)
+			}
+
+			maxSendMsgSize := config.GRPC.MaxSendMsgSize
+			if maxSendMsgSize == 0 {
+				maxSendMsgSize = serverconfig.DefaultGRPCMaxSendMsgSize
+			}
+
+			maxRecvMsgSize := config.GRPC.MaxRecvMsgSize
+			if maxRecvMsgSize == 0 {
+				maxRecvMsgSize = serverconfig.DefaultGRPCMaxRecvMsgSize
+			}
+
+			grpcAddress := fmt.Sprintf("127.0.0.1:%s", port)
+
+			// If grpc is enabled, configure grpc client for grpc gateway and json-rpc.
+			grpcClient, err := grpc.Dial(
+				grpcAddress,
+				grpc.WithTransportCredentials(insecure.NewCredentials()),
+				grpc.WithDefaultCallOptions(
+					grpc.ForceCodec(codec.NewProtoCodec(clientCtx.InterfaceRegistry).GRPCCodec()),
+					grpc.MaxCallRecvMsgSize(maxRecvMsgSize),
+					grpc.MaxCallSendMsgSize(maxSendMsgSize),
+				),
+			)
+			if err != nil {
+				return err
+			}
+
+			clientCtx = clientCtx.WithGRPCClient(grpcClient)
+			ctx.Logger.Debug("gRPC client assigned to client context", "address", grpcAddress)
+		}
+	}
+
+	var apiSrv *api.Server
+	if config.API.Enable {
 		apiSrv = api.New(clientCtx, ctx.Logger.With("server", "api"))
 		app.RegisterAPIRoutes(apiSrv, config.API)
 		errCh := make(chan error)

x/evm/keeper/grpc_query.go

@@ -106,7 +106,7 @@ func (k Keeper) ValidatorAccount(c context.Context, req *types.QueryValidatorAcc
 
 	validator, found := k.stakingKeeper.GetValidatorByConsAddr(ctx, consAddr)
 	if !found {
-		return nil, nil
+		return nil, fmt.Errorf("validator not found for %s", consAddr.String())
 	}
 
 	accAddr := sdk.AccAddress(validator.GetOperator())