From 03b601b594870e62b75fc62872fd105bbc769195 Mon Sep 17 00:00:00 2001
From: Pavel Karpy <carpawell@nspcc.ru>
Date: Thu, 17 Feb 2022 15:43:09 +0300
Subject: [PATCH] [#1183] node: Init notificator on startup

It uses logger as a notification writer. NATS messaging will be implemented
later.

Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
---
 cmd/neofs-node/main.go           |   1 +
 cmd/neofs-node/notificator.go    | 129 +++++++++++++++++++++++++++++++
 pkg/services/notificator/deps.go |   4 +-
 3 files changed, 132 insertions(+), 2 deletions(-)
 create mode 100644 cmd/neofs-node/notificator.go

diff --git a/cmd/neofs-node/main.go b/cmd/neofs-node/main.go
index bf88c0b41..7accbf5ce 100644
--- a/cmd/neofs-node/main.go
+++ b/cmd/neofs-node/main.go
@@ -80,6 +80,7 @@ func initApp(c *cfg) {
 	initProfiler(c)
 	initMetrics(c)
 	initControlService(c)
+	initNotification(c)
 
 	fatalOnErr(c.cfgObject.cfgLocalStorage.localStorage.Open())
 	fatalOnErr(c.cfgObject.cfgLocalStorage.localStorage.Init())
diff --git a/cmd/neofs-node/notificator.go b/cmd/neofs-node/notificator.go
new file mode 100644
index 000000000..1be2e597c
--- /dev/null
+++ b/cmd/neofs-node/notificator.go
@@ -0,0 +1,129 @@
+package main
+
+import (
+	"fmt"
+
+	"github.com/mr-tron/base58"
+	nodeconfig "github.com/nspcc-dev/neofs-node/cmd/neofs-node/config/node"
+	"github.com/nspcc-dev/neofs-node/pkg/local_object_storage/engine"
+	"github.com/nspcc-dev/neofs-node/pkg/morph/event"
+	"github.com/nspcc-dev/neofs-node/pkg/morph/event/netmap"
+	"github.com/nspcc-dev/neofs-node/pkg/services/notificator"
+	objectSDK "github.com/nspcc-dev/neofs-sdk-go/object"
+	addressSDK "github.com/nspcc-dev/neofs-sdk-go/object/address"
+	"go.uber.org/zap"
+)
+
+type simpleNotificationWriter struct {
+	l *zap.Logger
+}
+
+func (s simpleNotificationWriter) Notify(topic string, address *addressSDK.Address) {
+	s.l.Debug("got notification to write",
+		zap.String("topic", topic),
+		zap.Stringer("address", address),
+	)
+}
+
+type notificationSource struct {
+	e            *engine.StorageEngine
+	l            *zap.Logger
+	defaultTopic string
+}
+
+func (n *notificationSource) Iterate(epoch uint64, handler func(topic string, addr *addressSDK.Address)) {
+	log := n.l.With(zap.Uint64("epoch", epoch))
+
+	listRes, err := n.e.ListContainers(engine.ListContainersPrm{})
+	if err != nil {
+		log.Error("notificator: could not list containers", zap.Error(err))
+		return
+	}
+
+	filters := objectSDK.NewSearchFilters()
+	filters.AddNotificationEpochFilter(epoch)
+
+	selectPrm := new(engine.SelectPrm)
+	selectPrm.WithFilters(filters)
+
+	for _, c := range listRes.Containers() {
+		selectPrm.WithContainerID(c)
+
+		selectRes, err := n.e.Select(selectPrm)
+		if err != nil {
+			log.Error("notificator: could not select objects from container",
+				zap.Stringer("cid", c),
+				zap.Error(err),
+			)
+			continue
+		}
+
+		for _, a := range selectRes.AddressList() {
+			err = n.processAddress(a, handler)
+			if err != nil {
+				log.Error("notificator: could not process object",
+					zap.Stringer("address", a),
+					zap.Error(err),
+				)
+				continue
+			}
+		}
+	}
+
+	log.Debug("notificator: finished processing object notifications")
+}
+
+func (n *notificationSource) processAddress(
+	a *addressSDK.Address,
+	h func(topic string, addr *addressSDK.Address),
+) error {
+	prm := new(engine.HeadPrm)
+	prm.WithAddress(a)
+
+	res, err := n.e.Head(prm)
+	if err != nil {
+		return err
+	}
+
+	ni, err := res.Header().NotificationInfo()
+	if err != nil {
+		return fmt.Errorf("could not retreive notification topic from object: %w", err)
+	}
+
+	topic := ni.Topic()
+
+	if topic == "" {
+		topic = n.defaultTopic
+	}
+
+	h(topic, a)
+
+	return nil
+}
+
+func initNotification(c *cfg) {
+	if nodeconfig.Notification(c.appCfg).Enabled() {
+		topic := nodeconfig.Notification(c.appCfg).DefaultTopic()
+
+		if topic == "" {
+			topic = base58.Encode(c.cfgNodeInfo.localInfo.PublicKey())
+		}
+
+		n := notificator.New(new(notificator.Prm).
+			SetLogger(c.log).
+			SetNotificationSource(
+				&notificationSource{
+					e:            c.cfgObject.cfgLocalStorage.localStorage,
+					l:            c.log,
+					defaultTopic: topic,
+				}).
+			SetWriter(simpleNotificationWriter{l: c.log}),
+		)
+
+		addNewEpochAsyncNotificationHandler(c, func(e event.Event) {
+			ev := e.(netmap.NewEpoch)
+
+			n.ProcessEpoch(ev.EpochNumber())
+		})
+	}
+}
diff --git a/pkg/services/notificator/deps.go b/pkg/services/notificator/deps.go
index db0c2ded1..2f7af0939 100644
--- a/pkg/services/notificator/deps.go
+++ b/pkg/services/notificator/deps.go
@@ -12,7 +12,7 @@ type NotificationSource interface {
 // NotificationWriter notifies all the subscribers
 // about new object notifications.
 type NotificationWriter interface {
-	// Notify must send string representation of the object
-	// address into the specified topic.
+	// Notify must notify about an event generated
+	// from an object with a specific topic.
 	Notify(topic string, address *objectSDKAddress.Address)
 }