perf: expose and reduce message publish latency

server/topic.go

@@ -20,6 +20,7 @@ import (
 
 	"github.com/tinode/chat/server/auth"
 	"github.com/tinode/chat/server/logs"
+	immetrics "github.com/tinode/chat/server/metrics"
 	"github.com/tinode/chat/server/moderation"
 	"github.com/tinode/chat/server/store"
 	"github.com/tinode/chat/server/store/types"
@@ -1362,7 +1363,9 @@ func (t *Topic) saveAndBroadcastMessage(msg *ClientComMessage, asUid types.Uid,
 		store.Relations != nil && store.Store != nil && store.Store.IsOpen() {
 		peer := t.p2pOtherUser(asUid)
 		if !peer.IsZero() {
+			started := time.Now()
 			canSend, _, err := store.Relations.CanSendP2P(t.tenantID, asUid, peer)
+			immetrics.ObserveMessagePublishStage("p2p", "relationship_check", started, err)
 			if err != nil {
 				logs.Warn.Printf("topic[%s]: failed to check p2p relationship: %v", t.name, err)
 				msg.sess.queueOut(ErrUnknown(msg.Id, t.original(asUid), msg.Timestamp))
@@ -1375,6 +1378,7 @@ func (t *Topic) saveAndBroadcastMessage(msg *ClientComMessage, asUid types.Uid,
 		}
 	}
 
+	persistStarted := time.Now()
 	saveResult, err := saveMessageMaybeKafka(context.Background(), t.tenantID,
 		&types.Message{
 			ObjHeader: types.ObjHeader{CreatedAt: msg.Timestamp},
@@ -1385,6 +1389,13 @@ func (t *Topic) saveAndBroadcastMessage(msg *ClientComMessage, asUid types.Uid,
 			Head:      head,
 			Content:   content,
 		}, attachments, (pud.modeGiven & pud.modeWant).IsReader())
+	kind := "other"
+	if t.cat == types.TopicCatP2P {
+		kind = "p2p"
+	} else if t.cat == types.TopicCatGrp {
+		kind = "group"
+	}
+	immetrics.ObserveMessagePublishStage(kind, "save", persistStarted, err)
 	if err != nil {
 		logs.Warn.Printf("topic[%s]: failed to save message: %v", t.name, err)
 		msg.sess.queueOut(ErrUnknown(msg.Id, t.original(asUid), msg.Timestamp))