[FAB-11646] Add interceptors to comm.GRPCServer

Adds the ability to set unary and stream
interceptors when configuring comm.GRPCServer
instances.

Adds the grpc-middleware library in order to
allow chaining of interceptors.
NOTE: had to remove unused package folders
manually and add grpc-middleware to the
noverify list due to hashes not matching for
symlinks across OS versions.

Change-Id: I0c9baa570ea84aa4be8377dedd0ada30c7e7a291
Signed-off-by: Gari Singh <gari.r.singh@gmail.com>

Author: mastersingh24

Gopkg.lock

@@ -12,6 +12,10 @@ required = [
 ignored = [
 ]
 
+noverify = [
+    "github.com/grpc-ecosystem/go-grpc-middleware"
+]
+
 [[constraint]]
   name = "github.com/Knetic/govaluate"
   version = "3.0.0"
@@ -158,7 +162,10 @@ ignored = [
       name = "github.com/coreos/etcd"
       non-go = false
 
-
 [[constraint]]
   name = "go.uber.org/zap"
   version = "1.9.0"
+
+[[constraint]]
+  name = "github.com/grpc-ecosystem/go-grpc-middleware"
+  version = "1.0.0"

Gopkg.toml

@@ -50,6 +50,12 @@ type ServerConfig struct {
 	SecOpts *SecureOptions
 	// KaOpts defines the keepalive parameters
 	KaOpts *KeepaliveOptions
+	// StreamInterceptors specifies a list of interceptors to apply to
+	// streaming RPCs.  They are executed in order.
+	StreamInterceptors []grpc.StreamServerInterceptor
+	// UnaryInterceptors specifies a list of interceptors to apply to unary
+	// RPCs.  They are executed in order.
+	UnaryInterceptors []grpc.UnaryServerInterceptor
 }
 
 // ClientConfig defines the parameters for configuring a GRPCClient instance

core/comm/config.go

@@ -15,6 +15,7 @@ import (
 	"sync"
 	"sync/atomic"
 
+	"github.com/grpc-ecosystem/go-grpc-middleware"
 	"google.golang.org/grpc"
 )
 
@@ -130,6 +131,21 @@ func NewGRPCServerFromListener(listener net.Listener, serverConfig ServerConfig)
 	serverOpts = append(
 		serverOpts,
 		grpc.ConnectionTimeout(serverConfig.ConnectionTimeout))
+	// set the interceptors
+	if len(serverConfig.StreamInterceptors) > 0 {
+		serverOpts = append(
+			serverOpts,
+			grpc.StreamInterceptor(
+				grpc_middleware.ChainStreamServer(
+					serverConfig.StreamInterceptors...)))
+	}
+	if len(serverConfig.UnaryInterceptors) > 0 {
+		serverOpts = append(
+			serverOpts,
+			grpc.UnaryInterceptor(
+				grpc_middleware.ChainUnaryServer(
+					serverConfig.UnaryInterceptors...)))
+	}
 
 	grpcServer.server = grpc.NewServer(serverOpts...)