fix: start GRPCWebServer in goroutine (backport #9704)

CHANGELOG.md

@@ -35,6 +35,11 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 # Changelog
 
+## [v0.43.0-rc2](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.43.0-rc2) - 2021-07-19
+
+### Bug Fixes
+
+* (server) [#9704](https://github.com/cosmos/cosmos-sdk/pull/9704) Start GRPCWebServer in goroutine, avoid blocking other services from starting.
 
 ## [v0.43.0-rc1](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.43.0-rc1) - 2021-07-14
 

server/grpc/grpc_web.go

@@ -1,12 +1,15 @@
 package grpc
 
 import (
+	"fmt"
 	"net/http"
+	"time"
 
 	"github.com/improbable-eng/grpc-web/go/grpcweb"
 	"google.golang.org/grpc"
 
 	"github.com/cosmos/cosmos-sdk/server/config"
+	"github.com/cosmos/cosmos-sdk/server/types"
 )
 
 // StartGRPCWeb starts a gRPC-Web server on the given address.
@@ -28,8 +31,18 @@ func StartGRPCWeb(grpcSrv *grpc.Server, config config.Config) (*http.Server, err
 		Addr:    config.GRPCWeb.Address,
 		Handler: http.HandlerFunc(handler),
 	}
-	if err := grpcWebSrv.ListenAndServe(); err != nil {
+
+	errCh := make(chan error)
+	go func() {
+		if err := grpcWebSrv.ListenAndServe(); err != nil {
+			errCh <- fmt.Errorf("[grpc] failed to serve: %w", err)
+		}
+	}()
+
+	select {
+	case err := <-errCh:
 		return nil, err
+	case <-time.After(types.ServerStartTime): // assume server started successfully
+		return grpcWebSrv, nil
 	}
-	return grpcWebSrv, nil
 }

server/grpc/server.go

@@ -54,7 +54,7 @@ func StartGRPCServer(clientCtx client.Context, app types.Application, address st
 	select {
 	case err := <-errCh:
 		return nil, err
-	case <-time.After(5 * time.Second): // assume server started successfully
+	case <-time.After(types.ServerStartTime): // assume server started successfully
 		return grpcSrv, nil
 	}
 }

server/start.go

@@ -314,7 +314,7 @@ func startInProcess(ctx *Context, clientCtx client.Context, appCreator types.App
 		select {
 		case err := <-errCh:
 			return err
-		case <-time.After(5 * time.Second): // assume server started successfully
+		case <-time.After(types.ServerStartTime): // assume server started successfully
 		}
 	}
 
@@ -368,7 +368,7 @@ func startInProcess(ctx *Context, clientCtx client.Context, appCreator types.App
 		select {
 		case err := <-errCh:
 			return err
-		case <-time.After(5 * time.Second): // assume server started successfully
+		case <-time.After(types.ServerStartTime): // assume server started successfully
 		}
 	}
 

server/types/app.go

@@ -3,6 +3,7 @@ package types
 import (
 	"encoding/json"
 	"io"
+	"time"
 
 	"github.com/gogo/protobuf/grpc"
 	"github.com/spf13/cobra"
@@ -16,6 +17,10 @@ import (
 	"github.com/cosmos/cosmos-sdk/server/config"
 )
 
+// ServerStartTime defines the time duration that the server need to stay running after startup
+// for the startup be considered successful
+const ServerStartTime = 5 * time.Second
+
 type (
 	// AppOptions defines an interface that is passed into an application
 	// constructor, typically used to set BaseApp options that are either supplied

testutil/network/util.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/cosmos/cosmos-sdk/server/api"
 	servergrpc "github.com/cosmos/cosmos-sdk/server/grpc"
+	srvtypes "github.com/cosmos/cosmos-sdk/server/types"
 	authtypes "github.com/cosmos/cosmos-sdk/x/auth/types"
 	banktypes "github.com/cosmos/cosmos-sdk/x/bank/types"
 	"github.com/cosmos/cosmos-sdk/x/genutil"
@@ -90,7 +91,7 @@ func startInProcess(cfg Config, val *Validator) error {
 		select {
 		case err := <-errCh:
 			return err
-		case <-time.After(5 * time.Second): // assume server started successfully
+		case <-time.After(srvtypes.ServerStartTime): // assume server started successfully
 		}
 
 		val.api = apiSrv
@@ -105,21 +106,10 @@ func startInProcess(cfg Config, val *Validator) error {
 		val.grpc = grpcSrv
 
 		if val.AppConfig.GRPCWeb.Enable {
-			errCh1 := make(chan error)
-			go func() {
-				grpcWeb, err := servergrpc.StartGRPCWeb(grpcSrv, *val.AppConfig)
-				if err != nil {
-					errCh1 <- err
-				}
-
-				val.grpcWeb = grpcWeb
-			}()
-			select {
-			case err := <-errCh1:
+			val.grpcWeb, err = servergrpc.StartGRPCWeb(grpcSrv, *val.AppConfig)
+			if err != nil {
 				return err
-			case <-time.After(5 * time.Second): // assume server started successfully
 			}
-
 		}
 	}