TUN-3593: /ready endpoint for k8s readiness. Move tunnel events out of UI package, into connection package.

cmd/cloudflared/tunnel/cmd.go

@@ -271,18 +271,6 @@ func StartServer(
 	// Wait for proxy-dns to come up (if used)
 	<-dnsReadySignal
 
-	metricsListener, err := listeners.Listen("tcp", c.String("metrics"))
-	if err != nil {
-		generalLogger.Errorf("Error opening metrics server listener: %s", err)
-		return errors.Wrap(err, "Error opening metrics server listener")
-	}
-	defer metricsListener.Close()
-	wg.Add(1)
-	go func() {
-		defer wg.Done()
-		errC <- metrics.ServeMetrics(metricsListener, shutdownC, generalLogger)
-	}()
-
 	go notifySystemd(connectedSignal)
 	if c.IsSet("pidfile") {
 		go writePidFile(connectedSignal, c.String("pidfile"), generalLogger)
@@ -331,12 +319,30 @@ func StartServer(
 		return errors.Wrap(err, "error setting up transport logger")
 	}
 
-	tunnelConfig, ingressRules, err := prepareTunnelConfig(c, buildInfo, version, generalLogger, transportLogger, namedTunnel, isUIEnabled)
+	readinessCh := make(chan connection.Event, 16)
+	uiCh := make(chan connection.Event, 16)
+	eventChannels := []chan connection.Event{
+		readinessCh,
+		uiCh,
+	}
+	tunnelConfig, ingressRules, err := prepareTunnelConfig(c, buildInfo, version, generalLogger, transportLogger, namedTunnel, isUIEnabled, eventChannels)
 	if err != nil {
 		generalLogger.Errorf("Couldn't start tunnel: %v", err)
 		return err
 	}
 
+	metricsListener, err := listeners.Listen("tcp", c.String("metrics"))
+	if err != nil {
+		generalLogger.Errorf("Error opening metrics server listener: %s", err)
+		return errors.Wrap(err, "Error opening metrics server listener")
+	}
+	defer metricsListener.Close()
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		errC <- metrics.ServeMetrics(metricsListener, shutdownC, readinessCh, generalLogger)
+	}()
+
 	ingressRules.StartOrigins(&wg, generalLogger, shutdownC, errC)
 
 	reconnectCh := make(chan origin.ReconnectSignal, 1)
@@ -363,7 +369,7 @@ func StartServer(
 		if err != nil {
 			return err
 		}
-		tunnelInfo.LaunchUI(ctx, generalLogger, transportLogger, logLevels, tunnelConfig.TunnelEventChan)
+		tunnelInfo.LaunchUI(ctx, generalLogger, transportLogger, logLevels, uiCh)
 	}
 
 	return waitToShutdown(&wg, errC, shutdownC, graceShutdownC, c.Duration("grace-period"), generalLogger)

cmd/cloudflared/tunnel/configuration.go

@@ -10,7 +10,6 @@ import (
 
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/buildinfo"
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/config"
-	"github.com/cloudflare/cloudflared/cmd/cloudflared/ui"
 	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/edgediscovery"
 	"github.com/cloudflare/cloudflared/h2mux"
@@ -160,7 +159,8 @@ func prepareTunnelConfig(
 	logger logger.Service,
 	transportLogger logger.Service,
 	namedTunnel *connection.NamedTunnelConfig,
-	uiIsEnabled bool,
+	isUIEnabled bool,
+	eventChans []chan connection.Event,
 ) (*origin.TunnelConfig, ingress.Ingress, error) {
 	isNamedTunnel := namedTunnel != nil
 
@@ -261,11 +261,6 @@ func prepareTunnelConfig(
 		MetricsUpdateFreq:  c.Duration("metrics-update-freq"),
 	}
 
-	var tunnelEventChan chan ui.TunnelEvent
-	if uiIsEnabled {
-		tunnelEventChan = make(chan ui.TunnelEvent, 16)
-	}
-
 	return &origin.TunnelConfig{
 		ConnectionConfig: connectionConfig,
 		BuildInfo:        buildInfo,
@@ -278,14 +273,14 @@ func prepareTunnelConfig(
 		LBPool:           c.String("lb-pool"),
 		Tags:             tags,
 		Logger:           logger,
-		Observer:         connection.NewObserver(transportLogger, tunnelEventChan),
+		Observer:         connection.NewObserver(transportLogger, eventChans, isUIEnabled),
 		ReportedVersion:  version,
 		Retries:          c.Uint("retries"),
 		RunFromTerminal:  isRunningFromTerminal(),
 		NamedTunnel:      namedTunnel,
 		ClassicTunnel:    classicTunnel,
 		MuxerConfig:      muxerConfig,
-		TunnelEventChan:  tunnelEventChan,
+		TunnelEventChans: eventChans,
 		ProtocolSelector: protocolSelector,
 		EdgeTLSConfigs:   edgeTLSConfigs,
 	}, ingressRules, nil

cmd/cloudflared/ui/launch_ui.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/ingress"
 	"github.com/cloudflare/cloudflared/logger"
 
@@ -15,24 +16,7 @@ import (
 
 type connState struct {
 	location string
-	state    status
+	state    connection.Status
-}
-
-type status int
-
-const (
-	Disconnected status = iota
-	Connected
-	Reconnecting
-	SetUrl
-	RegisteringTunnel
-)
-
-type TunnelEvent struct {
-	Index     uint8
-	EventType status
-	Location  string
-	Url       string
 }
 
 type uiModel struct {
@@ -69,7 +53,7 @@ func (data *uiModel) LaunchUI(
 	ctx context.Context,
 	generalLogger, transportLogger logger.Service,
 	logLevels []logger.Level,
-	tunnelEventChan <-chan TunnelEvent,
+	tunnelEventChan <-chan connection.Event,
 ) {
 	// Configure the logger to stream logs into the textview
 
@@ -138,14 +122,14 @@ func (data *uiModel) LaunchUI(
 				return
 			case event := <-tunnelEventChan:
 				switch event.EventType {
-				case Connected:
+				case connection.Connected:
 					data.setConnTableCell(event, connTable, palette)
-				case Disconnected, Reconnecting:
+				case connection.Disconnected, connection.Reconnecting:
 					data.changeConnStatus(event, connTable, generalLogger, palette)
-				case SetUrl:
+				case connection.SetURL:
-					tunnelHostText.SetText(event.Url)
+					tunnelHostText.SetText(event.URL)
-					data.edgeURL = event.Url
+					data.edgeURL = event.URL
-				case RegisteringTunnel:
+				case connection.RegisteringTunnel:
 					if data.edgeURL == "" {
 						tunnelHostText.SetText("Registering tunnel...")
 					}
@@ -175,7 +159,7 @@ func handleNewText(app *tview.Application, logTextView *tview.TextView) func() {
 	}
 }
 
-func (data *uiModel) changeConnStatus(event TunnelEvent, table *tview.Table, logger logger.Service, palette palette) {
+func (data *uiModel) changeConnStatus(event connection.Event, table *tview.Table, logger logger.Service, palette palette) {
 	index := int(event.Index)
 	// Get connection location and state
 	connState := data.getConnState(index)
@@ -187,10 +171,10 @@ func (data *uiModel) changeConnStatus(event TunnelEvent, table *tview.Table, log
 
 	locationState := event.Location
 
-	if event.EventType == Disconnected {
+	if event.EventType == connection.Disconnected {
-		connState.state = Disconnected
+		connState.state = connection.Disconnected
-	} else if event.EventType == Reconnecting {
+	} else if event.EventType == connection.Reconnecting {
-		connState.state = Reconnecting
+		connState.state = connection.Reconnecting
 		locationState = "Reconnecting..."
 	}
 
@@ -211,12 +195,12 @@ func (data *uiModel) getConnState(connID int) *connState {
 	return nil
 }
 
-func (data *uiModel) setConnTableCell(event TunnelEvent, table *tview.Table, palette palette) {
+func (data *uiModel) setConnTableCell(event connection.Event, table *tview.Table, palette palette) {
 	index := int(event.Index)
 	connectionNum := index + 1
 
 	// Update slice to keep track of connection location and state in UI table
-	data.connections[index].state = Connected
+	data.connections[index].state = connection.Connected
 	data.connections[index].location = event.Location
 
 	// Update text in table cell to show disconnected state
@@ -225,18 +209,18 @@ func (data *uiModel) setConnTableCell(event TunnelEvent, table *tview.Table, pal
 	table.SetCell(index, 0, cell)
 }
 
-func newCellText(palette palette, connectionNum int, location string, connectedStatus status) string {
+func newCellText(palette palette, connectionNum int, location string, connectedStatus connection.Status) string {
 	// HA connection indicator formatted as: "• #<CONNECTION_INDEX>: <COLO>",
 	//  where the left middle dot's color depends on the status of the connection
 	const connFmtString = "[%s]\u2022[%s] #%d: %s"
 
 	var dotColor string
 	switch connectedStatus {
-	case Connected:
+	case connection.Connected:
 		dotColor = palette.connected
-	case Disconnected:
+	case connection.Disconnected:
 		dotColor = palette.disconnected
-	case Reconnecting:
+	case connection.Reconnecting:
 		dotColor = palette.reconnecting
 	}
 

connection/connection_test.go

@@ -8,7 +8,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/cloudflare/cloudflared/cmd/cloudflared/ui"
 	"github.com/cloudflare/cloudflared/logger"
 	"github.com/gobwas/ws/wsutil"
 	"github.com/stretchr/testify/assert"
@@ -28,11 +27,12 @@ var (
 		Scheme: "https",
 		Host:   "connectiontest.argotunnel.com",
 	}
-	testTunnelEventChan = make(chan ui.TunnelEvent)
+	testTunnelEventChan = make(chan Event)
 	testObserver        = &Observer{
 		testLogger,
 		m,
-		testTunnelEventChan,
+		[]chan Event{testTunnelEventChan},
+		false,
 	}
 	testLargeResp = make([]byte, largeFileSize)
 )

connection/event.go

@@ -0,0 +1,25 @@
+package connection
+
+// Event is something that happened to a connection, e.g. disconnection or registration.
+type Event struct {
+	Index     uint8
+	EventType Status
+	Location  string
+	URL       string
+}
+
+// Status is the status of a connection.
+type Status int
+
+const (
+	// Disconnected means the connection to the edge was broken.
+	Disconnected Status = iota
+	// Connected means the connection to the edge was successfully established.
+	Connected
+	// Reconnecting means the connection to the edge is being re-established.
+	Reconnecting
+	// SetURL means this connection's tunnel was given a URL by the edge. Used for free tunnels.
+	SetURL
+	// RegisteringTunnel means the non-named tunnel is registering its connection.
+	RegisteringTunnel
+)

connection/observer.go

@@ -5,37 +5,35 @@ import (
 	"net/url"
 	"strings"
 
-	"github.com/cloudflare/cloudflared/cmd/cloudflared/ui"
 	"github.com/cloudflare/cloudflared/logger"
 	tunnelpogs "github.com/cloudflare/cloudflared/tunnelrpc/pogs"
 )
 
 type Observer struct {
 	logger.Service
-	metrics         *tunnelMetrics
+	metrics          *tunnelMetrics
-	tunnelEventChan chan<- ui.TunnelEvent
+	tunnelEventChans []chan Event
+	uiEnabled        bool
 }
 
-func NewObserver(logger logger.Service, tunnelEventChan chan<- ui.TunnelEvent) *Observer {
+func NewObserver(logger logger.Service, tunnelEventChans []chan Event, uiEnabled bool) *Observer {
 	return &Observer{
 		logger,
 		newTunnelMetrics(),
-		tunnelEventChan,
+		tunnelEventChans,
+		uiEnabled,
 	}
 }
 
 func (o *Observer) logServerInfo(connIndex uint8, location, msg string) {
-	// If launch-ui flag is set, send connect msg
+	o.sendEvent(Event{Index: connIndex, EventType: Connected, Location: location})
-	if o.tunnelEventChan != nil {
-		o.tunnelEventChan <- ui.TunnelEvent{Index: connIndex, EventType: ui.Connected, Location: location}
-	}
 	o.Infof(msg)
 	o.metrics.registerServerLocation(uint8ToString(connIndex), location)
 }
 
 func (o *Observer) logTrialHostname(registration *tunnelpogs.TunnelRegistration) error {
 	// Print out the user's trial zone URL in a nice box (if they requested and got one and UI flag is not set)
-	if o.tunnelEventChan == nil {
+	if !o.uiEnabled {
 		if registrationURL, err := url.Parse(registration.Url); err == nil {
 			for _, line := range asciiBox(trialZoneMsg(registrationURL.String()), 2) {
 				o.Info(line)
@@ -81,19 +79,27 @@ func trialZoneMsg(url string) []string {
 }
 
 func (o *Observer) sendRegisteringEvent() {
-	if o.tunnelEventChan != nil {
+	o.sendEvent(Event{EventType: RegisteringTunnel})
-		o.tunnelEventChan <- ui.TunnelEvent{EventType: ui.RegisteringTunnel}
-	}
 }
 
 func (o *Observer) sendConnectedEvent(connIndex uint8, location string) {
-	if o.tunnelEventChan != nil {
+	o.sendEvent(Event{Index: connIndex, EventType: Connected, Location: location})
-		o.tunnelEventChan <- ui.TunnelEvent{Index: connIndex, EventType: ui.Connected, Location: location}
-	}
 }
 
 func (o *Observer) sendURL(url string) {
-	if o.tunnelEventChan != nil {
+	o.sendEvent(Event{EventType: SetURL, URL: url})
-		o.tunnelEventChan <- ui.TunnelEvent{EventType: ui.SetUrl, Url: url}
+}
+
+func (o *Observer) SendReconnect(connIndex uint8) {
+	o.sendEvent(Event{Index: connIndex, EventType: Reconnecting})
+}
+
+func (o *Observer) SendDisconnect(connIndex uint8) {
+	o.sendEvent(Event{Index: connIndex, EventType: Disconnected})
+}
+
+func (o *Observer) sendEvent(e Event) {
+	for _, ch := range o.tunnelEventChans {
+		ch <- e
 	}
 }

metrics/metrics.go

@@ -12,6 +12,7 @@ import (
 
 	"golang.org/x/net/trace"
 
+	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/logger"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
@@ -22,22 +23,35 @@ const (
 	startupTime     = time.Millisecond * 500
 )
 
-func ServeMetrics(l net.Listener, shutdownC <-chan struct{}, logger logger.Service) (err error) {
+func newMetricsHandler(connectionEvents <-chan connection.Event, log logger.Service) *http.ServeMux {
+	readyServer := NewReadyServer(connectionEvents, log)
+	mux := http.NewServeMux()
+	mux.Handle("/metrics", promhttp.Handler())
+	mux.HandleFunc("/healthcheck", func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintf(w, "OK\n")
+	})
+	mux.Handle("/ready", readyServer)
+	return mux
+}
+
+func ServeMetrics(
+	l net.Listener,
+	shutdownC <-chan struct{},
+	connectionEvents <-chan connection.Event,
+	logger logger.Service,
+) (err error) {
 	var wg sync.WaitGroup
 	// Metrics port is privileged, so no need for further access control
 	trace.AuthRequest = func(*http.Request) (bool, bool) { return true, true }
 	// TODO: parameterize ReadTimeout and WriteTimeout. The maximum time we can
 	// profile CPU usage depends on WriteTimeout
+	h := newMetricsHandler(connectionEvents, logger)
 	server := &http.Server{
 		ReadTimeout:  10 * time.Second,
 		WriteTimeout: 10 * time.Second,
+		Handler:      h,
 	}
 
-	http.Handle("/metrics", promhttp.Handler())
-	http.Handle("/healthcheck", http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		fmt.Fprintf(w, "OK\n")
-	}))
-
 	wg.Add(1)
 	go func() {
 		defer wg.Done()

metrics/readiness.go

@@ -0,0 +1,80 @@
+package metrics
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"sync"
+
+	conn "github.com/cloudflare/cloudflared/connection"
+	"github.com/cloudflare/cloudflared/logger"
+)
+
+// ReadyServer serves HTTP 200 if the tunnel can serve traffic. Intended for k8s readiness checks.
+type ReadyServer struct {
+	sync.RWMutex
+	isConnected map[int]bool
+	log         logger.Service
+}
+
+// NewReadyServer initializes a ReadyServer and starts listening for dis/connection events.
+func NewReadyServer(connectionEvents <-chan conn.Event, log logger.Service) *ReadyServer {
+	rs := ReadyServer{
+		isConnected: make(map[int]bool, 0),
+		log:         log,
+	}
+	go func() {
+		for c := range connectionEvents {
+			switch c.EventType {
+			case conn.Connected:
+				rs.Lock()
+				rs.isConnected[int(c.Index)] = true
+				rs.Unlock()
+			case conn.Disconnected, conn.Reconnecting, conn.RegisteringTunnel:
+				rs.Lock()
+				rs.isConnected[int(c.Index)] = false
+				rs.Unlock()
+			case conn.SetURL:
+				continue
+			default:
+				rs.log.Errorf("Unknown connection event case %v", c)
+			}
+		}
+	}()
+	return &rs
+}
+
+type body struct {
+	Status           int `json:"status"`
+	ReadyConnections int `json:"readyConnections"`
+}
+
+// ServeHTTP responds with HTTP 200 if the tunnel is connected to the edge.
+func (rs *ReadyServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	statusCode, readyConnections := rs.makeResponse()
+	w.WriteHeader(statusCode)
+	body := body{
+		Status:           statusCode,
+		ReadyConnections: readyConnections,
+	}
+	msg, err := json.Marshal(body)
+	if err != nil {
+		fmt.Fprintf(w, `{"error": "%s"}`, err)
+	}
+	w.Write(msg)
+}
+
+// This is the bulk of the logic for ServeHTTP, broken into its own pure function
+// to make unit testing easy.
+func (rs *ReadyServer) makeResponse() (statusCode, readyConnections int) {
+	statusCode = http.StatusServiceUnavailable
+	rs.RLock()
+	defer rs.RUnlock()
+	for _, connected := range rs.isConnected {
+		if connected {
+			statusCode = http.StatusOK
+			readyConnections++
+		}
+	}
+	return statusCode, readyConnections
+}

metrics/readiness_test.go

@@ -0,0 +1,58 @@
+package metrics
+
+import (
+	"net/http"
+	"testing"
+)
+
+func TestReadyServer_makeResponse(t *testing.T) {
+	type fields struct {
+		isConnected map[int]bool
+	}
+	tests := []struct {
+		name                 string
+		fields               fields
+		wantOK               bool
+		wantReadyConnections int
+	}{
+		{
+			name: "One connection online => HTTP 200",
+			fields: fields{
+				isConnected: map[int]bool{
+					0: false,
+					1: false,
+					2: true,
+					3: false,
+				},
+			},
+			wantOK:               true,
+			wantReadyConnections: 1,
+		},
+		{
+			name: "No connections online => no HTTP 200",
+			fields: fields{
+				isConnected: map[int]bool{
+					0: false,
+					1: false,
+					2: false,
+					3: false,
+				},
+			},
+			wantReadyConnections: 0,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			rs := &ReadyServer{
+				isConnected: tt.fields.isConnected,
+			}
+			gotStatusCode, gotReadyConnections := rs.makeResponse()
+			if tt.wantOK && gotStatusCode != http.StatusOK {
+				t.Errorf("ReadyServer.makeResponse() gotStatusCode = %v, want ok = %v", gotStatusCode, tt.wantOK)
+			}
+			if gotReadyConnections != tt.wantReadyConnections {
+				t.Errorf("ReadyServer.makeResponse() gotReadyConnections = %v, want %v", gotReadyConnections, tt.wantReadyConnections)
+			}
+		})
+	}
+}

origin/tunnel.go

@@ -16,7 +16,6 @@ import (
 	"golang.org/x/sync/errgroup"
 
 	"github.com/cloudflare/cloudflared/cmd/cloudflared/buildinfo"
-	"github.com/cloudflare/cloudflared/cmd/cloudflared/ui"
 	"github.com/cloudflare/cloudflared/connection"
 	"github.com/cloudflare/cloudflared/edgediscovery"
 	"github.com/cloudflare/cloudflared/h2mux"
@@ -65,7 +64,7 @@ type TunnelConfig struct {
 	NamedTunnel      *connection.NamedTunnelConfig
 	ClassicTunnel    *connection.ClassicTunnelConfig
 	MuxerConfig      *connection.MuxerConfig
-	TunnelEventChan  chan ui.TunnelEvent
+	TunnelEventChans []chan connection.Event
 	ProtocolSelector connection.ProtocolSelector
 	EdgeTLSConfigs   map[connection.Protocol]*tls.Config
 }
@@ -235,10 +234,7 @@ func waitForBackoff(
 		return err
 	}
 
-	if config.TunnelEventChan != nil {
+	config.Observer.SendReconnect(connIndex)
-		config.TunnelEventChan <- ui.TunnelEvent{Index: connIndex, EventType: ui.Reconnecting}
-	}
-
 	config.Logger.Infof("Retrying connection %d in %s seconds, error %v", connIndex, duration, err)
 	protobackoff.Backoff(ctx)
 
@@ -288,12 +284,7 @@ func ServeTunnel(
 		}
 	}()
 
-	// If launch-ui flag is set, send disconnect msg
+	defer config.Observer.SendDisconnect(connIndex)
-	if config.TunnelEventChan != nil {
-		defer func() {
-			config.TunnelEventChan <- ui.TunnelEvent{Index: connIndex, EventType: ui.Disconnected}
-		}()
-	}
 
 	edgeConn, err := edgediscovery.DialEdge(ctx, dialTimeout, config.EdgeTLSConfigs[protocol], addr)
 	if err != nil {

origin/tunnel_test.go

@@ -47,6 +47,7 @@ func TestWaitForBackoffFallback(t *testing.T) {
 	config := &TunnelConfig{
 		Logger:           logger,
 		ProtocolSelector: protocolSelector,
+		Observer:         connection.NewObserver(nil, nil, false),
 	}
 	connIndex := uint8(1)
 

tunneldns/tunnel.go

@@ -80,7 +80,7 @@ func Run(c *cli.Context) error {
 		logger.Fatalf("Failed to open the metrics listener: %s", err)
 	}
 
-	go metrics.ServeMetrics(metricsListener, nil, logger)
+	go metrics.ServeMetrics(metricsListener, nil, nil, logger)
 
 	listener, err := CreateListener(c.String("address"), uint16(c.Uint("port")), c.StringSlice("upstream"), c.StringSlice("bootstrap"), logger)
 	if err != nil {