Support event subscriptions with glob wildcards (hashicorp#19205)

http/events.go

@@ -20,21 +20,21 @@ import (
 )
 
 type eventSubscribeArgs struct {
-	ctx       context.Context
-	logger    hclog.Logger
-	events    *eventbus.EventBus
-	ns        *namespace.Namespace
-	eventType logical.EventType
-	conn      *websocket.Conn
-	json      bool
+	ctx     context.Context
+	logger  hclog.Logger
+	events  *eventbus.EventBus
+	ns      *namespace.Namespace
+	pattern string
+	conn    *websocket.Conn
+	json    bool
 }
 
 // handleEventsSubscribeWebsocket runs forever, returning a websocket error code and reason
 // only if the connection closes or there was an error.
 func handleEventsSubscribeWebsocket(args eventSubscribeArgs) (websocket.StatusCode, string, error) {
 	ctx := args.ctx
 	logger := args.logger
-	ch, cancel, err := args.events.Subscribe(ctx, args.ns, args.eventType)
+	ch, cancel, err := args.events.Subscribe(ctx, args.ns, args.pattern)
 	if err != nil {
 		logger.Info("Error subscribing", "error", err)
 		return websocket.StatusUnsupportedData, "Error subscribing", nil
@@ -97,12 +97,11 @@ func handleEventsSubscribe(core *vault.Core, req *logical.Request) http.Handler
 		if ns.ID != namespace.RootNamespaceID {
 			prefix = fmt.Sprintf("/v1/%ssys/events/subscribe/", ns.Path)
 		}
-		eventTypeStr := strings.TrimSpace(strings.TrimPrefix(r.URL.Path, prefix))
-		if eventTypeStr == "" {
+		pattern := strings.TrimSpace(strings.TrimPrefix(r.URL.Path, prefix))
+		if pattern == "" {
 			respondError(w, http.StatusBadRequest, fmt.Errorf("did not specify eventType to subscribe to"))
 			return
 		}
-		eventType := logical.EventType(eventTypeStr)
 
 		json := false
 		jsonRaw := r.URL.Query().Get("json")
@@ -135,7 +134,7 @@ func handleEventsSubscribe(core *vault.Core, req *logical.Request) http.Handler
 			}
 		}()
 
-		closeStatus, closeReason, err := handleEventsSubscribeWebsocket(eventSubscribeArgs{ctx, logger, core.Events(), ns, eventType, conn, json})
+		closeStatus, closeReason, err := handleEventsSubscribeWebsocket(eventSubscribeArgs{ctx, logger, core.Events(), ns, pattern, conn, json})
 		if err != nil {
 			closeStatus = websocket.CloseStatus(err)
 			if closeStatus == -1 {

vault/eventbus/bus.go

@@ -16,10 +16,17 @@ import (
 	"github.com/hashicorp/go-uuid"
 	"github.com/hashicorp/vault/helper/namespace"
 	"github.com/hashicorp/vault/sdk/logical"
+	"github.com/ryanuber/go-glob"
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
-const defaultTimeout = 60 * time.Second
+const (
+	// eventTypeAll is purely internal to the event bus. We use it to send all
+	// events down one big firehose, and pipelines define their own filtering
+	// based on what each subscriber is interested in.
+	eventTypeAll   = "*"
+	defaultTimeout = 60 * time.Second
+)
 
 var (
 	ErrNotStarted              = errors.New("event broker has not been started")
@@ -45,16 +52,14 @@ type pluginEventBus struct {
 
 type asyncChanNode struct {
 	// TODO: add bounded deque buffer of *EventReceived
-	ctx       context.Context
-	ch        chan *logical.EventReceived
-	namespace *namespace.Namespace
-	logger    hclog.Logger
+	ctx    context.Context
+	ch     chan *logical.EventReceived
+	logger hclog.Logger
 
 	// used to close the connection
 	closeOnce  sync.Once
 	cancelFunc context.CancelFunc
 	pipelineID eventlogger.PipelineID
-	eventType  eventlogger.EventType
 	broker     *eventlogger.Broker
 }
 
@@ -97,7 +102,7 @@ func (bus *EventBus) SendInternal(ctx context.Context, ns *namespace.Namespace,
 	// We can't easily know when the Send is complete, so we can't call the cancel function.
 	// But, it is called automatically after bus.timeout, so there won't be any leak as long as bus.timeout is not too long.
 	ctx, _ = context.WithTimeout(ctx, bus.timeout)
-	_, err := bus.broker.Send(ctx, eventlogger.EventType(eventType), eventReceived)
+	_, err := bus.broker.Send(ctx, eventTypeAll, eventReceived)
 	if err != nil {
 		// if no listeners for this event type are registered, that's okay, the event
 		// will just not be sent anywhere
@@ -164,43 +169,53 @@ func NewEventBus(logger hclog.Logger) (*EventBus, error) {
 	}, nil
 }
 
-func (bus *EventBus) Subscribe(ctx context.Context, ns *namespace.Namespace, eventType logical.EventType) (<-chan *logical.EventReceived, context.CancelFunc, error) {
+func (bus *EventBus) Subscribe(ctx context.Context, ns *namespace.Namespace, pattern string) (<-chan *logical.EventReceived, context.CancelFunc, error) {
 	// subscriptions are still stored even if the bus has not been started
 	pipelineID, err := uuid.GenerateUUID()
 	if err != nil {
 		return nil, nil, err
 	}
 
-	nodeID, err := uuid.GenerateUUID()
+	filterNodeID, err := uuid.GenerateUUID()
+	if err != nil {
+		return nil, nil, err
+	}
+
+	filterNode := newFilterNode(ns, pattern)
+	err = bus.broker.RegisterNode(eventlogger.NodeID(filterNodeID), filterNode)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	sinkNodeID, err := uuid.GenerateUUID()
 	if err != nil {
 		return nil, nil, err
 	}
 
-	// TODO: should we have just one node per namespace, and handle all the routing ourselves?
 	ctx, cancel := context.WithCancel(ctx)
 	asyncNode := newAsyncNode(ctx, ns, bus.logger)
-	err = bus.broker.RegisterNode(eventlogger.NodeID(nodeID), asyncNode)
+	err = bus.broker.RegisterNode(eventlogger.NodeID(sinkNodeID), asyncNode)
 	if err != nil {
 		defer cancel()
 		return nil, nil, err
 	}
 
-	nodes := []eventlogger.NodeID{bus.formatterNodeID, eventlogger.NodeID(nodeID)}
+	nodes := []eventlogger.NodeID{eventlogger.NodeID(filterNodeID), bus.formatterNodeID, eventlogger.NodeID(sinkNodeID)}
 
 	pipeline := eventlogger.Pipeline{
 		PipelineID: eventlogger.PipelineID(pipelineID),
-		EventType:  eventlogger.EventType(eventType),
+		EventType:  eventTypeAll,
 		NodeIDs:    nodes,
 	}
 	err = bus.broker.RegisterPipeline(pipeline)
 	if err != nil {
 		defer cancel()
 		return nil, nil, err
 	}
+
 	addSubscriptions(1)
 	// add info needed to cancel the subscription
 	asyncNode.pipelineID = eventlogger.PipelineID(pipelineID)
-	asyncNode.eventType = eventlogger.EventType(eventType)
 	asyncNode.cancelFunc = cancel
 	return asyncNode.ch, asyncNode.Close, nil
 }
@@ -211,12 +226,32 @@ func (bus *EventBus) SetSendTimeout(timeout time.Duration) {
 	bus.timeout = timeout
 }
 
+func newFilterNode(ns *namespace.Namespace, pattern string) *eventlogger.Filter {
+	return &eventlogger.Filter{
+		Predicate: func(e *eventlogger.Event) (bool, error) {
+			eventRecv := e.Payload.(*logical.EventReceived)
+
+			// Drop if event is not in our namespace.
+			// TODO: add wildcard/child namespace processing here in some cases?
+			if eventRecv.Namespace != ns.Path {
+				return false, nil
+			}
+
+			// Filter for correct event type, including wildcards.
+			if !glob.Glob(pattern, eventRecv.EventType) {
+				return false, nil
+			}
+
+			return true, nil
+		},
+	}
+}
+
 func newAsyncNode(ctx context.Context, namespace *namespace.Namespace, logger hclog.Logger) *asyncChanNode {
 	return &asyncChanNode{
-		ctx:       ctx,
-		ch:        make(chan *logical.EventReceived),
-		namespace: namespace,
-		logger:    logger,
+		ctx:    ctx,
+		ch:     make(chan *logical.EventReceived),
+		logger: logger,
 	}
 }
 
@@ -225,7 +260,7 @@ func (node *asyncChanNode) Close() {
 	node.closeOnce.Do(func() {
 		defer node.cancelFunc()
 		if node.broker != nil {
-			err := node.broker.RemovePipeline(node.eventType, node.pipelineID)
+			err := node.broker.RemovePipeline(eventTypeAll, node.pipelineID)
 			if err != nil {
 				node.logger.Warn("Error removing pipeline for closing node", "error", err)
 			}
@@ -238,11 +273,6 @@ func (node *asyncChanNode) Process(ctx context.Context, e *eventlogger.Event) (*
 	// sends to the channel async in another goroutine
 	go func() {
 		eventRecv := e.Payload.(*logical.EventReceived)
-		// drop if event is not in our namespace
-		// TODO: add wildcard processing here in some cases?
-		if eventRecv.Namespace != node.namespace.Path {
-			return
-		}
 		var timeout bool
 		select {
 		case node.ch <- eventRecv:

vault/eventbus/bus_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/hashicorp/go-secure-stdlib/strutil"
 	"github.com/hashicorp/vault/helper/namespace"
 	"github.com/hashicorp/vault/sdk/logical"
 )
@@ -38,7 +39,7 @@ func TestBusBasics(t *testing.T) {
 		t.Errorf("Expected no error sending: %v", err)
 	}
 
-	ch, cancel, err := bus.Subscribe(ctx, namespace.RootNamespace, eventType)
+	ch, cancel, err := bus.Subscribe(ctx, namespace.RootNamespace, string(eventType))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -81,7 +82,7 @@ func TestNamespaceFiltering(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	ch, cancel, err := bus.Subscribe(ctx, namespace.RootNamespace, eventType)
+	ch, cancel, err := bus.Subscribe(ctx, namespace.RootNamespace, string(eventType))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -137,13 +138,13 @@ func TestBus2Subscriptions(t *testing.T) {
 	eventType2 := logical.EventType("someType2")
 	bus.Start()
 
-	ch1, cancel1, err := bus.Subscribe(ctx, namespace.RootNamespace, eventType1)
+	ch1, cancel1, err := bus.Subscribe(ctx, namespace.RootNamespace, string(eventType1))
 	if err != nil {
 		t.Fatal(err)
 	}
 	defer cancel1()
 
-	ch2, cancel2, err := bus.Subscribe(ctx, namespace.RootNamespace, eventType2)
+	ch2, cancel2, err := bus.Subscribe(ctx, namespace.RootNamespace, string(eventType2))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -222,7 +223,7 @@ func TestBusSubscriptionsCancel(t *testing.T) {
 			received := atomic.Int32{}
 
 			for i := 0; i < create; i++ {
-				ch, cancelFunc, err := bus.Subscribe(ctx, namespace.RootNamespace, eventType)
+				ch, cancelFunc, err := bus.Subscribe(ctx, namespace.RootNamespace, string(eventType))
 				if err != nil {
 					t.Fatal(err)
 				}
@@ -297,3 +298,78 @@ func waitFor(t *testing.T, maxWait time.Duration, f func() bool) {
 	}
 	t.Error("Timeout waiting for condition")
 }
+
+// TestBusWildcardSubscriptions tests that a single subscription can receive
+// multiple event types using * for glob patterns.
+func TestBusWildcardSubscriptions(t *testing.T) {
+	bus, err := NewEventBus(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	ctx := context.Background()
+
+	fooEventType := logical.EventType("kv/foo")
+	barEventType := logical.EventType("kv/bar")
+	bus.Start()
+
+	ch1, cancel1, err := bus.Subscribe(ctx, namespace.RootNamespace, "kv/*")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer cancel1()
+
+	ch2, cancel2, err := bus.Subscribe(ctx, namespace.RootNamespace, "*/bar")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer cancel2()
+
+	event1, err := logical.NewEvent()
+	if err != nil {
+		t.Fatal(err)
+	}
+	event2, err := logical.NewEvent()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	err = bus.SendInternal(ctx, namespace.RootNamespace, nil, barEventType, event2)
+	if err != nil {
+		t.Error(err)
+	}
+	err = bus.SendInternal(ctx, namespace.RootNamespace, nil, fooEventType, event1)
+	if err != nil {
+		t.Error(err)
+	}
+
+	timeout := time.After(1 * time.Second)
+	// Expect to receive both events on ch1, which subscribed to kv/*
+	var ch1Seen []string
+	for i := 0; i < 2; i++ {
+		select {
+		case message := <-ch1:
+			ch1Seen = append(ch1Seen, message.Event.ID())
+		case <-timeout:
+			t.Error("Timeout waiting for event1")
+		}
+	}
+	if len(ch1Seen) != 2 {
+		t.Errorf("Expected 2 events but got: %v", ch1Seen)
+	} else {
+		if !strutil.StrListContains(ch1Seen, event1.ID()) {
+			t.Errorf("Did not find %s event1 ID in ch1seen", event1.ID())
+		}
+		if !strutil.StrListContains(ch1Seen, event2.ID()) {
+			t.Errorf("Did not find %s event2 ID in ch1seen", event2.ID())
+		}
+	}
+	// Expect to receive just kv/bar on ch2, which subscribed to */bar
+	select {
+	case message := <-ch2:
+		if message.Event.ID() != event2.ID() {
+			t.Errorf("Got unexpected message: %v", message)
+		}
+	case <-timeout:
+		t.Error("Timeout waiting for event2")
+	}
+}

vault/events_test.go

@@ -19,7 +19,7 @@ func TestCanSendEventsFromBuiltinPlugin(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	ch, cancel, err := c.events.Subscribe(ctx, namespace.RootNamespace, logical.EventType(eventType))
+	ch, cancel, err := c.events.Subscribe(ctx, namespace.RootNamespace, eventType)
 	if err != nil {
 		t.Fatal(err)
 	}