Updates to KV Watcher.

go_test.mod

@@ -1,11 +1,20 @@
 module github.com/nats-io/nats.go
 
-go 1.16
+go 1.17
 
 require (
 	github.com/golang/protobuf v1.4.2
-	github.com/nats-io/nats-server/v2 v2.7.2-0.20220201004847-b23ed778684c
+	github.com/nats-io/nats-server/v2 v2.7.2
 	github.com/nats-io/nkeys v0.3.0
 	github.com/nats-io/nuid v1.0.1
 	google.golang.org/protobuf v1.23.0
 )
+
+require (
+	github.com/klauspost/compress v1.13.4 // indirect
+	github.com/minio/highwayhash v1.0.1 // indirect
+	github.com/nats-io/jwt/v2 v2.2.1-0.20220113022732-58e87895b296 // indirect
+	golang.org/x/crypto v0.0.0-20220112180741-5e0467b6c7ce // indirect
+	golang.org/x/sys v0.0.0-20220111092808-5a964db01320 // indirect
+	golang.org/x/time v0.0.0-20211116232009-f0f3c7e86c11 // indirect
+)

go_test.sum

@@ -17,8 +17,8 @@ github.com/minio/highwayhash v1.0.1 h1:dZ6IIu8Z14VlC0VpfKofAhCy74wu/Qb5gcn52yWoz
 github.com/minio/highwayhash v1.0.1/go.mod h1:BQskDq+xkJ12lmlUUi7U0M5Swg3EWR+dLTk+kldvVxY=
 github.com/nats-io/jwt/v2 v2.2.1-0.20220113022732-58e87895b296 h1:vU9tpM3apjYlLLeY23zRWJ9Zktr5jp+mloR942LEOpY=
 github.com/nats-io/jwt/v2 v2.2.1-0.20220113022732-58e87895b296/go.mod h1:0tqz9Hlu6bCBFLWAASKhE5vUA4c24L9KPUUgvwumE/k=
-github.com/nats-io/nats-server/v2 v2.7.2-0.20220201004847-b23ed778684c h1:TfLMCHvaj2YSNrgiEWQiXA344lWqPmX3xOLtZj/ywlA=
-github.com/nats-io/nats-server/v2 v2.7.2-0.20220201004847-b23ed778684c/go.mod h1:tckmrt0M6bVaDT3kmh9UrIq/CBOBBse+TpXQi5ldaa8=
+github.com/nats-io/nats-server/v2 v2.7.2 h1:+LEN8m0+jdCkiGc884WnDuxR+qj80/5arj+szKuRpRI=
+github.com/nats-io/nats-server/v2 v2.7.2/go.mod h1:tckmrt0M6bVaDT3kmh9UrIq/CBOBBse+TpXQi5ldaa8=
 github.com/nats-io/nats.go v1.13.1-0.20220121202836-972a071d373d/go.mod h1:BPko4oXsySz4aSWeFgOHLZs3G4Jq4ZAyE6/zMCxRT6w=
 github.com/nats-io/nkeys v0.3.0 h1:cgM5tL53EvYRU+2YLXIK0G2mJtK12Ft9oeooSZMA2G8=
 github.com/nats-io/nkeys v0.3.0/go.mod h1:gvUNGjVcM2IPr5rCsRsC6Wb3Hr2CQAm08dsxtV6A5y4=

js.go

@@ -1,4 +1,4 @@
-// Copyright 2020-2021 The NATS Authors
+// Copyright 2020-2022 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
@@ -919,6 +919,9 @@ type ConsumerConfig struct {
 
 	// Ephemeral inactivity threshold.
 	InactiveThreshold time.Duration `json:"inactive_threshold,omitempty"`
+
+	// Internal Use
+	Direct bool `json:"direct,omitempty"`
 }
 
 // ConsumerInfo is the info from a JetStream consumer.
@@ -968,6 +971,7 @@ type jsSub struct {
 	consumer string
 	stream   string
 	deliver  string
+	pending  uint64
 	pull     bool
 	dc       bool // Delete JS consumer
 
@@ -977,6 +981,9 @@ type jsSub struct {
 	sseq    uint64
 	ccreq   *createConsumerRequest
 
+	// Optional watcher
+	w *watcher
+
 	// Heartbeats and Flow Control handling from push consumers.
 	hbc    *time.Timer
 	hbi    time.Duration
@@ -1312,6 +1319,7 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
 		o.cfg.AckPolicy = AckNonePolicy
 		o.cfg.MaxDeliver = 1
 		o.cfg.AckWait = 22 * time.Hour // Just set to something known, not utilized.
+		o.cfg.Direct = true
 		if !hasHeartbeats {
 			o.cfg.Heartbeat = orderedHeartbeatsInterval
 		}
@@ -1518,6 +1526,8 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
 				if err != nil {
 					return nil, err
 				}
+				jsi.pending = info.NumPending
+
 				if !isPullMode {
 					// We can't reuse the channel, so if one was passed, we need to create a new one.
 					if isSync {
@@ -1534,6 +1544,7 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
 					}
 					jsi.deliver = deliver
 					jsi.hbi = info.Config.Heartbeat
+
 					// Recreate the subscription here.
 					sub, err = nc.subscribe(jsi.deliver, queue, cb, ch, isSync, jsi)
 					if err != nil {
@@ -1552,6 +1563,7 @@ func (js *js) subscribe(subj, queue string, cb MsgHandler, ch chan *Msg, isSync,
 			// Since the library created the JS consumer, it will delete it on Unsubscribe()/Drain()
 			sub.mu.Lock()
 			sub.jsi.dc = true
+			jsi.pending = info.NumPending
 			// If this is an ephemeral, we did not have a consumer name, we get it from the info
 			// after the AddConsumer returns.
 			if consumer == _EMPTY_ {
@@ -1860,7 +1872,7 @@ func (sub *Subscription) activityCheck() {
 	}
 
 	active := jsi.active
-	jsi.hbc.Reset(jsi.hbi)
+	jsi.hbc.Reset(jsi.hbi * hbcThresh)
 	jsi.active = false
 	nc := sub.conn
 	sub.mu.Unlock()
@@ -1888,7 +1900,7 @@ func (sub *Subscription) scheduleHeartbeatCheck() {
 	if jsi.hbc == nil {
 		jsi.hbc = time.AfterFunc(jsi.hbi*hbcThresh, sub.activityCheck)
 	} else {
-		jsi.hbc.Reset(jsi.hbi)
+		jsi.hbc.Reset(jsi.hbi * hbcThresh)
 	}
 }
 

kv.go

@@ -1,4 +1,4 @@
-// Copyright 2021 The NATS Authors
+// Copyright 2021-2022 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
@@ -306,6 +306,11 @@ func (js *js) CreateKeyValue(cfg *KeyValueConfig) (KeyValue, error) {
 		DenyDelete:        true,
 	}
 
+	// If we are at server version 2.7.2 or above use DiscardNew. We can not use DiscardNew for 2.7.1 or below.
+	if js.nc.serverMinVersion(2, 7, 2) {
+		scfg.Discard = DiscardNew
+	}
+
 	if _, err := js.AddStream(scfg); err != nil {
 		return nil, err
 	}
@@ -626,14 +631,16 @@ func (kv *kvs) Watch(keys string, opts ...WatchOpt) (KeyWatcher, error) {
 	}
 
 	var initDoneMarker bool
+	initPending, received := uint64(0), uint64(0)
 
 	// Could be a pattern so don't check for validity as we normally do.
 	var b strings.Builder
 	b.WriteString(kv.pre)
 	b.WriteString(keys)
 	keys = b.String()
 
-	w := &watcher{updates: make(chan KeyValueEntry, 32)}
+	// We will block below on placing items on the chan. That is by design.
+	w := &watcher{updates: make(chan KeyValueEntry, 256)}
 
 	update := func(m *Msg) {
 		tokens, err := getMetadataFields(m.Reply)
@@ -655,32 +662,32 @@ func (kv *kvs) Watch(keys string, opts ...WatchOpt) (KeyWatcher, error) {
 			}
 		}
 		delta := uint64(parseNum(tokens[ackNumPendingTokenPos]))
-		entry := &kve{
-			bucket:   kv.name,
-			key:      subj,
-			value:    m.Data,
-			revision: uint64(parseNum(tokens[ackStreamSeqTokenPos])),
-			created:  time.Unix(0, parseNum(tokens[ackTimestampSeqTokenPos])),
-			delta:    delta,
-			op:       op,
-		}
 		if !o.ignoreDeletes || (op != KeyValueDelete && op != KeyValuePurge) {
+			entry := &kve{
+				bucket:   kv.name,
+				key:      subj,
+				value:    m.Data,
+				revision: uint64(parseNum(tokens[ackStreamSeqTokenPos])),
+				created:  time.Unix(0, parseNum(tokens[ackTimestampSeqTokenPos])),
+				delta:    delta,
+				op:       op,
+			}
 			w.updates <- entry
 		}
-		// Check if done initial values.
-		if !initDoneMarker && delta == 0 {
-			initDoneMarker = true
-			w.updates <- nil
+		// Check if done and initial values.
+		if !initDoneMarker {
+			received++
+			// We set this on the first trip through..
+			if initPending == 0 {
+				initPending = delta
+			}
+			if received > initPending || delta == 0 {
+				initDoneMarker = true
+				w.updates <- nil
+			}
 		}
 	}
 
-	// Check if we have anything pending.
-	_, err := kv.js.GetLastMsg(kv.stream, keys)
-	if err == ErrMsgNotFound {
-		initDoneMarker = true
-		w.updates <- nil
-	}
-
 	// Used ordered consumer to deliver results.
 	subOpts := []SubOpt{OrderedConsumer()}
 	if !o.includeHistory {
@@ -696,6 +703,18 @@ func (kv *kvs) Watch(keys string, opts ...WatchOpt) (KeyWatcher, error) {
 	if err != nil {
 		return nil, err
 	}
+	// Track watcher.
+	sub.jsi.w = w
+	// Set us up to close when the waitForMessages func returns.
+	sub.pDone = func() {
+		close(w.updates)
+	}
+	// Check on pending count.
+	if sub.jsi.pending == 0 {
+		initDoneMarker = true
+		w.updates <- nil
+	}
+
 	w.sub = sub
 	return w, nil
 }

nats.go

@@ -158,6 +158,7 @@ var (
 	ErrConsumerNotActive            = errors.New("nats: consumer not active")
 	ErrMsgNotFound                  = errors.New("nats: message not found")
 	ErrMsgAlreadyAckd               = errors.New("nats: message was already acknowledged")
+	ErrStreamInfoMaxSubjects        = errors.New("nats: subject details would exceed maximum allowed")
 )
 
 func init() {
@@ -586,6 +587,7 @@ type Subscription struct {
 	pHead *Msg
 	pTail *Msg
 	pCond *sync.Cond
+	pDone func()
 
 	// Pending stats, async subscriptions, high-speed etc.
 	pMsgs       int
@@ -2696,7 +2698,13 @@ func (nc *Conn) waitForMsgs(s *Subscription) {
 		}
 		s.pHead = m.next
 	}
+	// Now check for pDone
+	done := s.pDone
 	s.mu.Unlock()
+
+	if done != nil {
+		done()
+	}
 }
 
 // Used for debugging and simulating loss for certain tests.
@@ -3928,7 +3936,8 @@ func (nc *Conn) removeSub(s *Subscription) {
 	s.mch = nil
 
 	// If JS subscription then stop HB timer.
-	if jsi := s.jsi; jsi != nil {
+	jsi := s.jsi
+	if jsi != nil {
 		if jsi.hbc != nil {
 			jsi.hbc.Stop()
 			jsi.hbc = nil

test/kv_test.go

@@ -1,4 +1,4 @@
-// Copyright 2022 The NATS Authors
+// Copyright 2021-2022 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
@@ -17,6 +17,7 @@ import (
 	"context"
 	"fmt"
 	"reflect"
+	"regexp"
 	"strconv"
 	"strings"
 	"testing"
@@ -258,6 +259,44 @@ func TestKeyValueWatchContext(t *testing.T) {
 	}
 }
 
+func TestKeyValueWatchContextUpdates(t *testing.T) {
+	s := RunBasicJetStreamServer()
+	defer shutdownJSServerAndRemoveStorage(t, s)
+
+	nc, js := jsClient(t, s)
+	defer nc.Close()
+
+	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{Bucket: "WATCHCTX"})
+	expectOk(t, err)
+
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	watcher, err := kv.WatchAll(nats.Context(ctx))
+	expectOk(t, err)
+	defer watcher.Stop()
+
+	// Pull the initial state done marker which is nil.
+	select {
+	case v := <-watcher.Updates():
+		if v != nil {
+			t.Fatalf("Expected nil marker, got %+v", v)
+		}
+	case <-time.After(time.Second):
+		t.Fatalf("Did not receive nil marker like expected")
+	}
+
+	// Fire a timer and cancel the context after 250ms.
+	time.AfterFunc(250*time.Millisecond, cancel)
+
+	// Make sure canceling will break us out here.
+	select {
+	case <-watcher.Updates():
+	case <-time.After(5 * time.Second):
+		t.Fatalf("Did not break out like expected")
+	}
+}
+
 func TestKeyValueBindStore(t *testing.T) {
 	s := RunBasicJetStreamServer()
 	defer shutdownJSServerAndRemoveStorage(t, s)
@@ -466,6 +505,48 @@ func TestKeyValueKeys(t *testing.T) {
 	}
 }
 
+func TestKeyValueDiscardNew(t *testing.T) {
+	s := RunBasicJetStreamServer()
+	defer shutdownJSServerAndRemoveStorage(t, s)
+
+	nc, js := jsClient(t, s)
+	defer nc.Close()
+
+	kv, err := js.CreateKeyValue(&nats.KeyValueConfig{Bucket: "TEST", History: 1, MaxBytes: 256})
+	expectOk(t, err)
+
+	vc := func() (major, minor, patch int) {
+		semVerRe := regexp.MustCompile(`\Av?([0-9]+)\.?([0-9]+)?\.?([0-9]+)?`)
+		m := semVerRe.FindStringSubmatch(nc.ConnectedServerVersion())
+		expectOk(t, err)
+		major, err = strconv.Atoi(m[1])
+		expectOk(t, err)
+		minor, err = strconv.Atoi(m[2])
+		expectOk(t, err)
+		patch, err = strconv.Atoi(m[3])
+		expectOk(t, err)
+		return major, minor, patch
+	}
+
+	major, minor, patch := vc()
+	status, err := kv.Status()
+	expectOk(t, err)
+	kvs := status.(*nats.KeyValueBucketStatus)
+	si := kvs.StreamInfo()
+
+	// If we are 2.7.1 or below DiscardOld should be used.
+	// If 2.7.2 or above should be DiscardNew
+	if major <= 2 && minor <= 7 && patch <= 1 {
+		if si.Config.Discard != nats.DiscardOld {
+			t.Fatalf("Expected Discard Old for server version %d.%d.%d", major, minor, patch)
+		}
+	} else {
+		if si.Config.Discard != nats.DiscardNew {
+			t.Fatalf("Expected Discard New for server version %d.%d.%d", major, minor, patch)
+		}
+	}
+}
+
 // Helpers
 
 func client(t *testing.T, s *server.Server, opts ...nats.Option) *nats.Conn {