Send version info to rendezvous server.

Include agent string and version when binding to the rendezvous
server. There's default values that can be overridden using
WithVersion() when instantiating the rendezvous client.

Fixes: #2

rendezvous/client.go

@@ -13,6 +13,7 @@ import (
 	"github.com/gorilla/websocket"
 	"github.com/psanford/wormhole-william/internal/crypto"
 	"github.com/psanford/wormhole-william/rendezvous/internal/msgs"
+	"github.com/psanford/wormhole-william/version"
 )
 
 // NewClient returns a Rendezvous client. URL is the websocket
@@ -21,8 +22,8 @@ import (
 // AppID is the application identity string of the client.
 //
 // Two clients can only communicate if they have the same AppID.
-func NewClient(url, sideID, appID string) *Client {
-	return &Client{
+func NewClient(url, sideID, appID string, opts ...ClientOption) *Client {
+	c := &Client{
 		url:         url,
 		sideID:      sideID,
 		appID:       appID,
@@ -33,6 +34,12 @@ func NewClient(url, sideID, appID string) *Client {
 
 		pendingMsgWaiters: make(map[uint32]chan uint32),
 	}
+
+	for _, opt := range opts {
+		opt.setValue(c)
+	}
+
+	return c
 }
 
 type pendingMsg struct {
@@ -52,6 +59,9 @@ type Client struct {
 
 	nameplate string
 
+	agentString  string
+	agentVersion string
+
 	wsClient *websocket.Conn
 
 	mailboxMsgs           []MailboxEvent
@@ -511,10 +521,26 @@ func (c *Client) prepareMsg(msg interface{}) (string, error) {
 	return id, nil
 }
 
+func (c *Client) agentID() (string, string) {
+	agent := c.agentString
+	if agent == "" {
+		agent = version.AgentString
+	}
+	v := c.agentVersion
+	if v == "" {
+		v = version.AgentVersion
+	}
+
+	return agent, v
+}
+
 func (c *Client) bind(ctx context.Context, side, appID string) error {
+	agent, version := c.agentID()
+
 	bind := msgs.Bind{
-		Side:  side,
-		AppID: appID,
+		Side:          side,
+		AppID:         appID,
+		ClientVersion: []string{agent, version},
 	}
 
 	_, err := c.sendAndWait(ctx, &bind)

rendezvous/client_test.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/psanford/wormhole-william/internal/crypto"
 	"github.com/psanford/wormhole-william/rendezvous/rendezvousservertest"
+	"github.com/psanford/wormhole-william/version"
 )
 
 func TestBasicClient(t *testing.T) {
@@ -30,6 +31,15 @@ func TestBasicClient(t *testing.T) {
 		t.Fatalf("MOTD got=%s expected=%s", info.MOTD, rendezvousservertest.TestMotd)
 	}
 
+	gotAgents := ts.Agents()
+	expectAgents := [][]string{
+		[]string{version.AgentString, version.AgentVersion},
+	}
+
+	if !reflect.DeepEqual(gotAgents, expectAgents) {
+		t.Fatalf("got agents=%v expected=%v", gotAgents, expectAgents)
+	}
+
 	nameplate, err := c0.CreateMailbox(ctx)
 	if err != nil {
 		t.Fatal(err)
@@ -100,3 +110,33 @@ func TestBasicClient(t *testing.T) {
 	default:
 	}
 }
+
+func TestCustomUserAgent(t *testing.T) {
+	ts := rendezvousservertest.NewServer()
+	defer ts.Close()
+
+	side0 := crypto.RandSideID()
+	appID := "nightclubs-reasonableness"
+
+	agentString := "deafening-buttermilk"
+	agentVersion := "v1.2.3"
+	c0 := NewClient(ts.WebSocketURL(), side0, appID, WithVersion(agentString, agentVersion))
+
+	ctx := context.Background()
+
+	_, err := c0.Connect(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	gotAgents := ts.Agents()
+	expectAgents := [][]string{
+		[]string{agentString, agentVersion},
+	}
+
+	if !reflect.DeepEqual(gotAgents, expectAgents) {
+		t.Fatalf("got agents=%v expected=%v", gotAgents, expectAgents)
+	}
+
+	c0.Close(ctx, "")
+}

rendezvous/internal/msgs/msgs.go

@@ -19,6 +19,9 @@ type Bind struct {
 	ID    string `json:"id"`
 	Side  string `json:"side"`
 	AppID string `json:"appid"`
+	// ClientVersion is by convention a two value array
+	// of [client_id, version]
+	ClientVersion []string `json:"client_version"`
 }
 
 // Client sent aollocate message

rendezvous/options.go

@@ -0,0 +1,24 @@
+package rendezvous
+
+type ClientOption interface {
+	setValue(*Client)
+}
+
+type versionOption struct {
+	agentString  string
+	agentVersion string
+}
+
+func (o *versionOption) setValue(c *Client) {
+	c.agentString = o.agentString
+	c.agentVersion = o.agentVersion
+}
+
+// WithVersion returns a ClientOption to override the default client
+// identifier and version reported to the rendezvous server.
+func WithVersion(agentID string, version string) ClientOption {
+	return &versionOption{
+		agentString:  agentID,
+		agentVersion: version,
+	}
+}

rendezvous/rendezvousservertest/rendezvousservertest.go

@@ -25,6 +25,7 @@ type TestServer struct {
 	mu         sync.Mutex
 	mailboxes  map[string]*mailbox
 	nameplates map[int16]string
+	agents     [][]string
 }
 
 func NewServer() *TestServer {
@@ -40,6 +41,10 @@ func NewServer() *TestServer {
 	return ts
 }
 
+func (ts *TestServer) Agents() [][]string {
+	return ts.agents
+}
+
 func (ts *TestServer) WebSocketURL() string {
 	u, err := url.Parse(ts.URL)
 	if err != nil {
@@ -236,6 +241,10 @@ func (ts *TestServer) handleWS(w http.ResponseWriter, r *http.Request) {
 				continue
 			}
 
+			ts.mu.Lock()
+			ts.agents = append(ts.agents, m.ClientVersion)
+			ts.mu.Unlock()
+
 			sideID = m.Side
 		case *msgs.Allocate:
 			ackMsg(m.ID)

version/version.go

@@ -0,0 +1,8 @@
+package version
+
+var (
+	// Default Agent identifier sent to rendezvous server
+	AgentString = "go-william"
+	// Default Agent version sent to rendezvous server
+	AgentVersion = "v1.0.0"
+)