Add Server Options

Adds a new struct of server options which can be used to override default properties. A new options-accepting NewServer function has been created to supersede the New method, which is now deprecated.

server/server.go

@@ -5,11 +5,13 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"log"
 	"net"
 	"strconv"
 	"sync/atomic"
 	"time"
 
+	"github.com/logrusorgru/aurora"
 	"github.com/mochi-co/mqtt/server/events"
 	"github.com/mochi-co/mqtt/server/internal/circ"
 	"github.com/mochi-co/mqtt/server/internal/clients"
@@ -64,6 +66,7 @@ type Server struct {
 	inline    inlineMessages       // channels for direct publishing.
 	Events    events.Events        // overrideable event hooks.
 	Store     persistence.Store    // a persistent storage backend if desired.
+	Options   *Options             // configurable server options.
 	Listeners *listeners.Listeners // listeners are network interfaces which listen for new connections.
 	Clients   *clients.Clients     // clients which are known to the broker.
 	Topics    *topics.Index        // an index of topic filter subscriptions and retained messages.
@@ -73,17 +76,38 @@ type Server struct {
 	done      chan bool            // indicate that the server is ending.
 }
 
+// Options contains configurable options for the server.
+type Options struct {
+	// BufferSize overrides the default buffer size (circ.DefaultBufferSize) for the client buffers.
+	BufferSize int
+
+	// BufferBlockSize overrides the default buffer block size (DefaultBlockSize) for the client buffers.
+	BufferBlockSize int
+}
+
 // inlineMessages contains channels for handling inline (direct) publishing.
 type inlineMessages struct {
 	done chan bool           // indicate that the server is ending.
 	pub  chan packets.Packet // a channel of packets to publish to clients
 }
 
-// New returns a new instance of an MQTT broker.
+// New returns a new instance of MQTT server with no options.
+// This method has been deprecated and will be removed in a future release.
+// Please use NewServer instead.
 func New() *Server {
+	log.Println(aurora.Red("mqtt.New() has been deprecated and will be removed in a future release - please use mqtt.NewServer(opts *Options) instead!"))
+	return NewServer(nil)
+}
+
+// NewServer returns a new instance of an MQTT broker with optional values where applicable.
+func NewServer(opts *Options) *Server {
+	if opts == nil {
+		opts = new(Options)
+	}
+
 	s := &Server{
 		done:     make(chan bool),
-		bytepool: circ.NewBytesPool(circ.DefaultBufferSize),
+		bytepool: circ.NewBytesPool(opts.BufferSize),
 		Clients:  clients.New(),
 		Topics:   topics.New(),
 		System: &system.Info{
@@ -95,7 +119,8 @@ func New() *Server {
 			done: make(chan bool),
 			pub:  make(chan packets.Packet, 1024),
 		},
-		Events: events.Events{},
+		Events:  events.Events{},
+		Options: opts,
 	}
 
 	// Expose server stats using the system listener so it can be used in the
@@ -238,8 +263,8 @@ func (s *Server) EstablishConnection(lid string, c net.Conn, ac auth.Controller)
 	xbw := s.bytepool.Get() // and for sending.
 
 	cl := clients.NewClient(c,
-		circ.NewReaderFromSlice(0, xbr),
-		circ.NewWriterFromSlice(0, xbw),
+		circ.NewReaderFromSlice(s.Options.BufferBlockSize, xbr),
+		circ.NewWriterFromSlice(s.Options.BufferBlockSize, xbw),
 		s.System,
 	)