diff --git a/codec.go b/codec.go
index cb27ec6..b92b63b 100644
--- a/codec.go
+++ b/codec.go
@@ -2,7 +2,6 @@ package grpc
 
 import (
 	"encoding/json"
-	"fmt"
 	"strings"
 
 	b "bytes"
@@ -71,11 +70,19 @@ func (w wrapCodec) Unmarshal(data []byte, v interface{}) error {
 }
 
 func (protoCodec) Marshal(v interface{}) ([]byte, error) {
-	return proto.Marshal(v.(proto.Message))
+	m, ok := v.(proto.Message)
+	if !ok {
+		return nil, codec.ErrInvalidMessage
+	}
+	return proto.Marshal(m)
 }
 
 func (protoCodec) Unmarshal(data []byte, v interface{}) error {
-	return proto.Unmarshal(data, v.(proto.Message))
+	m, ok := v.(proto.Message)
+	if !ok {
+		return codec.ErrInvalidMessage
+	}
+	return proto.Unmarshal(data, m)
 }
 
 func (protoCodec) Name() string {
@@ -85,7 +92,6 @@ func (protoCodec) Name() string {
 func (jsonCodec) Marshal(v interface{}) ([]byte, error) {
 	if pb, ok := v.(proto.Message); ok {
 		s, err := jsonpbMarshaler.MarshalToString(pb)
-
 		return []byte(s), err
 	}
 
@@ -109,7 +115,7 @@ func (jsonCodec) Name() string {
 func (bytesCodec) Marshal(v interface{}) ([]byte, error) {
 	b, ok := v.(*[]byte)
 	if !ok {
-		return nil, fmt.Errorf("failed to marshal: %v is not type of *[]byte", v)
+		return nil, codec.ErrInvalidMessage
 	}
 	return *b, nil
 }
@@ -117,7 +123,7 @@ func (bytesCodec) Marshal(v interface{}) ([]byte, error) {
 func (bytesCodec) Unmarshal(data []byte, v interface{}) error {
 	b, ok := v.(*[]byte)
 	if !ok {
-		return fmt.Errorf("failed to unmarshal: %v is not type of *[]byte", v)
+		return codec.ErrInvalidMessage
 	}
 	*b = data
 	return nil
diff --git a/context.go b/context.go
new file mode 100644
index 0000000..0b246d7
--- /dev/null
+++ b/context.go
@@ -0,0 +1,16 @@
+package grpc
+
+import (
+	"context"
+
+	"github.com/micro/go-micro/v2/server"
+)
+
+func setServerOption(k, v interface{}) server.Option {
+	return func(o *server.Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}
diff --git a/grpc.go b/grpc.go
index b21c58e..001ea1b 100644
--- a/grpc.go
+++ b/grpc.go
@@ -143,9 +143,8 @@ func (g *grpcServer) getMaxMsgSize() int {
 
 func (g *grpcServer) getCredentials() credentials.TransportCredentials {
 	if g.opts.Context != nil {
-		if v := g.opts.Context.Value(tlsAuth{}); v != nil {
-			tls := v.(*tls.Config)
-			return credentials.NewTLS(tls)
+		if v, ok := g.opts.Context.Value(tlsAuth{}).(*tls.Config); ok && v != nil {
+			return credentials.NewTLS(v)
 		}
 	}
 	return nil
@@ -156,15 +155,8 @@ func (g *grpcServer) getGrpcOptions() []grpc.ServerOption {
 		return nil
 	}
 
-	v := g.opts.Context.Value(grpcOptions{})
-
-	if v == nil {
-		return nil
-	}
-
-	opts, ok := v.([]grpc.ServerOption)
-
-	if !ok {
+	opts, ok := g.opts.Context.Value(grpcOptions{}).([]grpc.ServerOption)
+	if !ok || opts == nil {
 		return nil
 	}
 
@@ -505,8 +497,8 @@ func (g *grpcServer) processStream(stream grpc.ServerStream, service *service, m
 func (g *grpcServer) newGRPCCodec(contentType string) (encoding.Codec, error) {
 	codecs := make(map[string]encoding.Codec)
 	if g.opts.Context != nil {
-		if v := g.opts.Context.Value(codecsKey{}); v != nil {
-			codecs = v.(map[string]encoding.Codec)
+		if v, ok := g.opts.Context.Value(codecsKey{}).(map[string]encoding.Codec); ok && v != nil {
+			codecs = v
 		}
 	}
 	if c, ok := codecs[contentType]; ok {
@@ -573,10 +565,10 @@ func (g *grpcServer) Subscribe(sb server.Subscriber) error {
 
 	g.Lock()
 
-	_, ok = g.subscribers[sub]
-	if ok {
+	if _, ok = g.subscribers[sub]; ok {
 		return fmt.Errorf("subscriber %v already exists", sub)
 	}
+
 	g.subscribers[sub] = nil
 	g.Unlock()
 	return nil
diff --git a/options.go b/options.go
index a46b914..64a8173 100644
--- a/options.go
+++ b/options.go
@@ -27,8 +27,8 @@ func Codec(contentType string, c encoding.Codec) server.Option {
 		if o.Context == nil {
 			o.Context = context.Background()
 		}
-		if v := o.Context.Value(codecsKey{}); v != nil {
-			codecs = v.(map[string]encoding.Codec)
+		if v, ok := o.Context.Value(codecsKey{}).(map[string]encoding.Codec); ok && v != nil {
+			codecs = v
 		}
 		codecs[contentType] = c
 		o.Context = context.WithValue(o.Context, codecsKey{}, codecs)
@@ -37,32 +37,17 @@ func Codec(contentType string, c encoding.Codec) server.Option {
 
 // AuthTLS should be used to setup a secure authentication using TLS
 func AuthTLS(t *tls.Config) server.Option {
-	return func(o *server.Options) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, tlsAuth{}, t)
-	}
+	return setServerOption(tlsAuth{}, t)
 }
 
 // Listener specifies the net.Listener to use instead of the default
 func Listener(l net.Listener) server.Option {
-	return func(o *server.Options) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, netListener{}, l)
-	}
+	return setServerOption(netListener{}, l)
 }
 
 // Options to be used to configure gRPC options
 func Options(opts ...grpc.ServerOption) server.Option {
-	return func(o *server.Options) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, grpcOptions{}, opts)
-	}
+	return setServerOption(grpcOptions{}, opts)
 }
 
 //
@@ -70,51 +55,25 @@ func Options(opts ...grpc.ServerOption) server.Option {
 // send.  Default maximum message size is 4 MB.
 //
 func MaxMsgSize(s int) server.Option {
-	return func(o *server.Options) {
-		if o.Context == nil {
-			o.Context = context.Background()
-		}
-		o.Context = context.WithValue(o.Context, maxMsgSizeKey{}, s)
-	}
+	return setServerOption(maxMsgSizeKey{}, s)
 }
 
 func newOptions(opt ...server.Option) server.Options {
 	opts := server.Options{
-		Codecs:   make(map[string]codec.NewCodec),
-		Metadata: map[string]string{},
+		Codecs:    make(map[string]codec.NewCodec),
+		Metadata:  map[string]string{},
+		Broker:    broker.DefaultBroker,
+		Registry:  registry.DefaultRegistry,
+		Transport: transport.DefaultTransport,
+		Address:   server.DefaultAddress,
+		Name:      server.DefaultName,
+		Id:        server.DefaultId,
+		Version:   server.DefaultVersion,
 	}
 
 	for _, o := range opt {
 		o(&opts)
 	}
 
-	if opts.Broker == nil {
-		opts.Broker = broker.DefaultBroker
-	}
-
-	if opts.Registry == nil {
-		opts.Registry = registry.DefaultRegistry
-	}
-
-	if opts.Transport == nil {
-		opts.Transport = transport.DefaultTransport
-	}
-
-	if len(opts.Address) == 0 {
-		opts.Address = server.DefaultAddress
-	}
-
-	if len(opts.Name) == 0 {
-		opts.Name = server.DefaultName
-	}
-
-	if len(opts.Id) == 0 {
-		opts.Id = server.DefaultId
-	}
-
-	if len(opts.Version) == 0 {
-		opts.Version = server.DefaultVersion
-	}
-
 	return opts
 }