Stream API options

* Stream API uses the same default values as the Channel API
* request size, reply size and reply timeout settable using
  functional options
* Added stream client example to show the stream API usage

Change-Id: Id599134a7f520fc19f7d770ed5e3de74a7936829
Signed-off-by: Vladimir Lavor <vlavor@cisco.com>

1 files changed, 42 insertions, 16 deletions

diff --git a/core/stream.go b/core/stream.go
index 61a9965..abe9d55 100644
--- a/core/stream.go
+++ b/core/stream.go
@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"reflect"
 	"sync/atomic"
+	"time"
 
 	"git.fd.io/govpp.git/api"
 )
@@ -29,36 +30,43 @@ type Stream struct {
 	conn    *Connection
 	ctx     context.Context
 	channel *Channel
+	// available options
+	requestSize  int
+	replySize    int
+	replyTimeout time.Duration
 }
 
-func (c *Connection) NewStream(ctx context.Context) (api.Stream, error) {
+func (c *Connection) NewStream(ctx context.Context, options ...api.StreamOption) (api.Stream, error) {
 	if c == nil {
 		return nil, errors.New("nil connection passed in")
 	}
-	// TODO: add stream options as variadic parameters for customizing:
-	// - request/reply channel size
-	// - reply timeout
-	// - retries
-	// - ???
+	s := &Stream{
+		conn: c,
+		ctx:  ctx,
+		// default options
+		requestSize:  RequestChanBufSize,
+		replySize:    ReplyChanBufSize,
+		replyTimeout: DefaultReplyTimeout,
+	}
 
-	// create new channel
-	chID := uint16(atomic.AddUint32(&c.maxChannelID, 1) & 0x7fff)
-	channel := newChannel(chID, c, c.codec, c, 10, 10)
+	// parse custom options
+	for _, option := range options {
+		option(s)
+	}
+	// create and store a new channel
+	s.id = atomic.AddUint32(&c.maxChannelID, 1) & 0x7fff
+	s.channel = newChannel(uint16(s.id), c, c.codec, c, s.requestSize, s.replySize)
+	s.channel.SetReplyTimeout(s.replyTimeout)
 
 	// store API channel within the client
 	c.channelsLock.Lock()
-	c.channels[chID] = channel
+	c.channels[uint16(s.id)] = s.channel
 	c.channelsLock.Unlock()
 
 	// Channel.watchRequests are not started here intentionally, because
 	// requests are sent directly by SendMsg.
 
-	return &Stream{
-		id:      uint32(chID),
-		conn:    c,
-		ctx:     ctx,
-		channel: channel,
-	}, nil
+	return s, nil
 }
 
 func (c *Connection) Invoke(ctx context.Context, req api.Message, reply api.Message) error {
@@ -123,6 +131,24 @@ func (s *Stream) RecvMsg() (api.Message, error) {
 	return msg, nil
 }
 
+func WithRequestSize(size int) api.StreamOption {
+	return func(stream api.Stream) {
+		stream.(*Stream).requestSize = size
+	}
+}
+
+func WithReplySize(size int) api.StreamOption {
+	return func(stream api.Stream) {
+		stream.(*Stream).replySize = size
+	}
+}
+
+func WithReplyTimeout(timeout time.Duration) api.StreamOption {
+	return func(stream api.Stream) {
+		stream.(*Stream).replyTimeout = timeout
+	}
+}
+
 func (s *Stream) recvReply() (*vppReply, error) {
 	if s.conn == nil {
 		return nil, errors.New("stream closed")