Merge pull request #41 from crosbymichael/interceptors

Add client and server unary interceptors

client.go

@@ -36,36 +36,48 @@ import (
 // closed.
 var ErrClosed = errors.New("ttrpc: closed")
 
+// Client for a ttrpc server
 type Client struct {
 	codec   codec
 	conn    net.Conn
 	channel *channel
 	calls   chan *callRequest
 
-	closed    chan struct{}
-	closeOnce sync.Once
-	closeFunc func()
-	done      chan struct{}
-	err       error
+	closed      chan struct{}
+	closeOnce   sync.Once
+	closeFunc   func()
+	done        chan struct{}
+	err         error
+	interceptor UnaryClientInterceptor
 }
 
+// ClientOpts configures a client
 type ClientOpts func(c *Client)
 
+// WithOnClose sets the close func whenever the client's Close() method is called
 func WithOnClose(onClose func()) ClientOpts {
 	return func(c *Client) {
 		c.closeFunc = onClose
 	}
 }
 
+// WithUnaryClientInterceptor sets the provided client interceptor
+func WithUnaryClientInterceptor(i UnaryClientInterceptor) ClientOpts {
+	return func(c *Client) {
+		c.interceptor = i
+	}
+}
+
 func NewClient(conn net.Conn, opts ...ClientOpts) *Client {
 	c := &Client{
-		codec:     codec{},
-		conn:      conn,
-		channel:   newChannel(conn),
-		calls:     make(chan *callRequest),
-		closed:    make(chan struct{}),
-		done:      make(chan struct{}),
-		closeFunc: func() {},
+		codec:       codec{},
+		conn:        conn,
+		channel:     newChannel(conn),
+		calls:       make(chan *callRequest),
+		closed:      make(chan struct{}),
+		done:        make(chan struct{}),
+		closeFunc:   func() {},
+		interceptor: defaultClientInterceptor,
 	}
 
 	for _, o := range opts {
@@ -107,7 +119,10 @@ func (c *Client) Call(ctx context.Context, service, method string, req, resp int
 		creq.TimeoutNano = dl.Sub(time.Now()).Nanoseconds()
 	}
 
-	if err := c.dispatch(ctx, creq, cresp); err != nil {
+	info := &UnaryClientInfo{
+		FullMethod: fullPath(service, method),
+	}
+	if err := c.interceptor(ctx, creq, cresp, info, c.dispatch); err != nil {
 		return err
 	}
 

config.go

@@ -19,9 +19,11 @@ package ttrpc
 import "github.com/pkg/errors"
 
 type serverConfig struct {
-	handshaker Handshaker
+	handshaker  Handshaker
+	interceptor UnaryServerInterceptor
 }
 
+// ServerOpt for configuring a ttrpc server
 type ServerOpt func(*serverConfig) error
 
 // WithServerHandshaker can be passed to NewServer to ensure that the
@@ -37,3 +39,14 @@ func WithServerHandshaker(handshaker Handshaker) ServerOpt {
 		return nil
 	}
 }
+
+// WithUnaryServerInterceptor sets the provided interceptor on the server
+func WithUnaryServerInterceptor(i UnaryServerInterceptor) ServerOpt {
+	return func(c *serverConfig) error {
+		if c.interceptor != nil {
+			return errors.New("only one interceptor allowed per server")
+		}
+		c.interceptor = i
+		return nil
+	}
+}

example/cmd/main.go

@@ -0,0 +1,135 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package main
+
+import (
+	context "context"
+	"encoding/json"
+	"errors"
+	"log"
+	"net"
+	"os"
+
+	ttrpc "github.com/containerd/ttrpc"
+	"github.com/containerd/ttrpc/example"
+	"github.com/gogo/protobuf/types"
+)
+
+const socket = "example-ttrpc-server"
+
+func main() {
+	if err := handle(); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func handle() error {
+	command := os.Args[1]
+	switch command {
+	case "server":
+		return server()
+	case "client":
+		return client()
+	default:
+		return errors.New("invalid command")
+	}
+}
+
+func serverIntercept(ctx context.Context, um ttrpc.Unmarshaler, i *ttrpc.UnaryServerInfo, m ttrpc.Method) (interface{}, error) {
+	log.Println("server interceptor")
+	dumpMetadata(ctx)
+	return m(ctx, um)
+}
+
+func clientIntercept(ctx context.Context, req *ttrpc.Request, resp *ttrpc.Response, i *ttrpc.UnaryClientInfo, invoker ttrpc.Invoker) error {
+	log.Println("client interceptor")
+	dumpMetadata(ctx)
+	return invoker(ctx, req, resp)
+}
+
+func dumpMetadata(ctx context.Context) {
+	md, ok := ttrpc.GetMetadata(ctx)
+	if !ok {
+		panic("no metadata")
+	}
+	if err := json.NewEncoder(os.Stdout).Encode(md); err != nil {
+		panic(err)
+	}
+}
+
+func server() error {
+	s, err := ttrpc.NewServer(
+		ttrpc.WithServerHandshaker(ttrpc.UnixSocketRequireSameUser()),
+		ttrpc.WithUnaryServerInterceptor(serverIntercept),
+	)
+	if err != nil {
+		return err
+	}
+	defer s.Close()
+	example.RegisterExampleService(s, &exampleServer{})
+
+	l, err := net.Listen("unix", socket)
+	if err != nil {
+		return err
+	}
+	defer func() {
+		l.Close()
+		os.Remove(socket)
+	}()
+	return s.Serve(context.Background(), l)
+}
+
+func client() error {
+	conn, err := net.Dial("unix", socket)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+
+	tc := ttrpc.NewClient(conn, ttrpc.WithUnaryClientInterceptor(clientIntercept))
+	client := example.NewExampleClient(tc)
+
+	r := &example.Method1Request{
+		Foo: os.Args[2],
+		Bar: os.Args[3],
+	}
+
+	ctx := context.Background()
+	md := ttrpc.Metadata{}
+	md.Set("name", "koye")
+	ctx = ttrpc.WithMetadata(ctx, md)
+
+	resp, err := client.Method1(ctx, r)
+	if err != nil {
+		return err
+	}
+	return json.NewEncoder(os.Stdout).Encode(resp)
+}
+
+type exampleServer struct {
+}
+
+func (s *exampleServer) Method1(ctx context.Context, r *example.Method1Request) (*example.Method1Response, error) {
+	return &example.Method1Response{
+		Foo: r.Foo,
+		Bar: r.Bar,
+	}, nil
+}
+
+func (s *exampleServer) Method2(ctx context.Context, r *example.Method1Request) (*types.Empty, error) {
+	return &types.Empty{}, nil
+}

interceptor.go

@@ -0,0 +1,50 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package ttrpc
+
+import "context"
+
+// UnaryServerInfo provides information about the server request
+type UnaryServerInfo struct {
+	FullMethod string
+}
+
+// UnaryClientInfo provides information about the client request
+type UnaryClientInfo struct {
+	FullMethod string
+}
+
+// Unmarshaler contains the server request data and allows it to be unmarshaled
+// into a concrete type
+type Unmarshaler func(interface{}) error
+
+// Invoker invokes the client's request and response from the ttrpc server
+type Invoker func(context.Context, *Request, *Response) error
+
+// UnaryServerInterceptor specifies the interceptor function for server request/response
+type UnaryServerInterceptor func(context.Context, Unmarshaler, *UnaryServerInfo, Method) (interface{}, error)
+
+// UnaryClientInterceptor specifies the interceptor function for client request/response
+type UnaryClientInterceptor func(context.Context, *Request, *Response, *UnaryClientInfo, Invoker) error
+
+func defaultServerInterceptor(ctx context.Context, unmarshal Unmarshaler, info *UnaryServerInfo, method Method) (interface{}, error) {
+	return method(ctx, unmarshal)
+}
+
+func defaultClientInterceptor(ctx context.Context, req *Request, resp *Response, _ *UnaryClientInfo, invoker Invoker) error {
+	return invoker(ctx, req, resp)
+}

server.go

@@ -53,10 +53,13 @@ func NewServer(opts ...ServerOpt) (*Server, error) {
 			return nil, err
 		}
 	}
+	if config.interceptor == nil {
+		config.interceptor = defaultServerInterceptor
+	}
 
 	return &Server{
 		config:      config,
-		services:    newServiceSet(),
+		services:    newServiceSet(config.interceptor),
 		done:        make(chan struct{}),
 		listeners:   make(map[net.Listener]struct{}),
 		connections: make(map[*serverConn]struct{}),

services.go

@@ -37,12 +37,14 @@ type ServiceDesc struct {
 }
 
 type serviceSet struct {
-	services map[string]ServiceDesc
+	services    map[string]ServiceDesc
+	interceptor UnaryServerInterceptor
 }
 
-func newServiceSet() *serviceSet {
+func newServiceSet(interceptor UnaryServerInterceptor) *serviceSet {
 	return &serviceSet{
-		services: make(map[string]ServiceDesc),
+		services:    make(map[string]ServiceDesc),
+		interceptor: interceptor,
 	}
 }
 
@@ -84,7 +86,11 @@ func (s *serviceSet) dispatch(ctx context.Context, serviceName, methodName strin
 		return nil
 	}
 
-	resp, err := method(ctx, unmarshal)
+	info := &UnaryServerInfo{
+		FullMethod: fullPath(serviceName, methodName),
+	}
+
+	resp, err := s.interceptor(ctx, unmarshal, info, method)
 	if err != nil {
 		return nil, err
 	}