feat(BRIDGE-37): Remote notification support

internal/services/notifications/metrics.go

@@ -0,0 +1,51 @@
+// Copyright (c) 2024 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package notifications
+
+import (
+	"time"
+
+	"github.com/ProtonMail/go-proton-api"
+)
+
+func generatedNotificationDisplayedMetric(status string, value int) proton.ObservabilityMetric {
+	// Value cannot be zero or negative
+	if value < 1 {
+		value = 1
+	}
+
+	return proton.ObservabilityMetric{
+		Name:      "bridge_remoteNotification_displayed_total",
+		Version:   1,
+		Timestamp: time.Now().Unix(),
+		Data: map[string]interface{}{
+			"Value": value,
+			"Labels": map[string]string{
+				"status": status,
+			},
+		},
+	}
+}
+
+func GenerateReceivedMetric(count int) proton.ObservabilityMetric {
+	return generatedNotificationDisplayedMetric("received", count)
+}
+
+func GenerateProcessedMetric(count int) proton.ObservabilityMetric {
+	return generatedNotificationDisplayedMetric("processed", count)
+}

internal/services/notifications/notification_test.go

@@ -0,0 +1,112 @@
+// Copyright (c) 2024 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package notifications
+
+import (
+	"testing"
+	"time"
+
+	"github.com/ProtonMail/go-proton-api"
+	"github.com/stretchr/testify/require"
+)
+
+func TestIsBodyBitfieldValid(t *testing.T) {
+	tests := []struct {
+		notification proton.NotificationEvent
+		isValid      bool
+	}{
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: ""}}, isValid: true},
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: "HELLO"}}, isValid: true},
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: "What is up?"}}, isValid: true},
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: "123 Hello"}}, isValid: true},
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: "\\123Hello"}}, isValid: false},
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: "\\123 Hello"}}, isValid: false},
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: "\\1test"}}, isValid: false},
+		{notification: proton.NotificationEvent{Payload: proton.NotificationPayload{Body: "\\1 test"}}, isValid: false},
+	}
+
+	for _, test := range tests {
+		isValid := isBodyBitfieldValid(test.notification)
+		require.Equal(t, isValid, !test.isValid)
+	}
+}
+
+// The notification TTL is defined as timestamp by server + predefined duration.
+func TestShouldSendAndStore(t *testing.T) {
+	getDirFn := func(dir string) func() (string, error) {
+		return func() (string, error) {
+			return dir, nil
+		}
+	}
+
+	dir1 := t.TempDir()
+	dir2 := t.TempDir()
+
+	store := NewStore(getDirFn(dir1))
+
+	notification1 := proton.NotificationEvent{ID: "1", Payload: proton.NotificationPayload{Title: "test1", Subtitle: "test1", Body: "test1"}, Time: time.Now().Unix()}
+	notification2 := proton.NotificationEvent{ID: "2", Payload: proton.NotificationPayload{Title: "test2", Subtitle: "test2", Body: "test2"}, Time: time.Now().Unix()}
+	notification3 := proton.NotificationEvent{ID: "3", Payload: proton.NotificationPayload{Title: "test3", Subtitle: "test3", Body: "test3"}, Time: time.Now().Unix()}
+	notificationAlt1 := proton.NotificationEvent{ID: "1", Payload: proton.NotificationPayload{Title: "testAlt1", Subtitle: "test1", Body: "test1"}, Time: time.Now().Unix()}
+	notificationAlt2 := proton.NotificationEvent{ID: "1", Payload: proton.NotificationPayload{Title: "test2", Subtitle: "testAlt2", Body: "test2"}, Time: time.Now().Unix()}
+
+	require.Equal(t, true, store.shouldSendAndStore(notification1))
+	require.Equal(t, true, store.shouldSendAndStore(notification2))
+	require.Equal(t, true, store.shouldSendAndStore(notification3))
+	require.Equal(t, true, store.shouldSendAndStore(notificationAlt1))
+	require.Equal(t, true, store.shouldSendAndStore(notificationAlt2))
+
+	require.Equal(t, false, store.shouldSendAndStore(notification1))
+	require.Equal(t, false, store.shouldSendAndStore(notification2))
+	require.Equal(t, false, store.shouldSendAndStore(notification3))
+
+	store = NewStore(getDirFn(dir1))
+
+	// These should be cached in the file
+	require.Equal(t, false, store.shouldSendAndStore(notification1))
+	require.Equal(t, false, store.shouldSendAndStore(notification2))
+	require.Equal(t, false, store.shouldSendAndStore(notification3))
+
+	store = NewStore(getDirFn(dir2))
+	timeOffset = 1 * time.Second
+
+	// We're basing the time based on when the notification is sent
+	// Let's reset it.
+	notification1 = proton.NotificationEvent{ID: "1", Payload: proton.NotificationPayload{Title: "test1", Subtitle: "test1", Body: "test1"}, Time: time.Now().Unix()}
+	notification2 = proton.NotificationEvent{ID: "2", Payload: proton.NotificationPayload{Title: "test2", Subtitle: "test2", Body: "test2"}, Time: time.Now().Unix()}
+	notification3 = proton.NotificationEvent{ID: "3", Payload: proton.NotificationPayload{Title: "test3", Subtitle: "test3", Body: "test3"}, Time: time.Now().Unix()}
+
+	require.Equal(t, true, store.shouldSendAndStore(notification1))
+	require.Equal(t, true, store.shouldSendAndStore(notification2))
+	require.Equal(t, true, store.shouldSendAndStore(notification3))
+
+	require.Equal(t, false, store.shouldSendAndStore(notification1))
+	require.Equal(t, false, store.shouldSendAndStore(notification2))
+	require.Equal(t, false, store.shouldSendAndStore(notification3))
+
+	time.Sleep(1200 * time.Millisecond)
+
+	require.Equal(t, true, store.shouldSendAndStore(notification1))
+	require.Equal(t, true, store.shouldSendAndStore(notification2))
+	require.Equal(t, true, store.shouldSendAndStore(notification3))
+
+	store = NewStore(getDirFn(dir2))
+	require.Equal(t, true, store.shouldSendAndStore(notification1))
+	require.Equal(t, true, store.shouldSendAndStore(notification2))
+	require.Equal(t, true, store.shouldSendAndStore(notification3))
+}

internal/services/notifications/service.go

@@ -0,0 +1,156 @@
+// Copyright (c) 2024 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package notifications
+
+import (
+	"context"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"github.com/ProtonMail/go-proton-api"
+	"github.com/ProtonMail/proton-bridge/v3/internal/events"
+	"github.com/ProtonMail/proton-bridge/v3/internal/logging"
+	"github.com/ProtonMail/proton-bridge/v3/internal/services/observability"
+	"github.com/ProtonMail/proton-bridge/v3/internal/services/orderedtasks"
+	"github.com/ProtonMail/proton-bridge/v3/internal/services/userevents"
+	"github.com/ProtonMail/proton-bridge/v3/internal/unleash"
+	"github.com/sirupsen/logrus"
+)
+
+type Service struct {
+	userID string
+
+	log *logrus.Entry
+
+	eventService   userevents.Subscribable
+	subscription   *userevents.EventChanneledSubscriber
+	eventPublisher events.EventPublisher
+
+	store *Store
+
+	getFlagValueFn            unleash.GetFlagValueFn
+	pushObservabilityMetricFn observability.PushObsMetricFn
+}
+
+const bitfieldRegexPattern = `^\\\d+`
+const disableNotificationsKillSwitch = "InboxBridgeEventLoopNotificationDisabled"
+
+func NewService(userID string, service userevents.Subscribable, eventPublisher events.EventPublisher, store *Store,
+	getFlagFn unleash.GetFlagValueFn, pushMetricFn observability.PushObsMetricFn) *Service {
+	return &Service{
+		userID: userID,
+
+		log: logrus.WithFields(logrus.Fields{
+			"user":    userID,
+			"service": "notification",
+		}),
+
+		eventService: service,
+		subscription: userevents.NewEventSubscriber(
+			fmt.Sprintf("notifications-%v", userID)),
+		eventPublisher: eventPublisher,
+
+		store: store,
+
+		getFlagValueFn:            getFlagFn,
+		pushObservabilityMetricFn: pushMetricFn,
+	}
+}
+
+func (s *Service) Start(ctx context.Context, group *orderedtasks.OrderedCancelGroup) {
+	group.Go(ctx, s.userID, "notification-service", s.run)
+}
+
+func (s *Service) run(ctx context.Context) {
+	s.log.Info("Starting service main loop")
+	defer s.log.Info("Exiting service main loop")
+
+	eventHandler := userevents.EventHandler{
+		NotificationHandler: s,
+	}
+
+	s.eventService.Subscribe(s.subscription)
+	defer s.eventService.Unsubscribe(s.subscription)
+
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case e, ok := <-s.subscription.OnEventCh():
+			if !ok {
+				continue
+			}
+			e.Consume(func(event proton.Event) error { return eventHandler.OnEvent(ctx, event) })
+		}
+	}
+}
+
+func (s *Service) HandleNotificationEvents(ctx context.Context, notificationEvents []proton.NotificationEvent) error {
+	if s.getFlagValueFn(disableNotificationsKillSwitch) {
+		s.log.Info("Received notification events. Skipping as kill switch is enabled.")
+		return nil
+	}
+
+	s.log.Debug("Handling notification events")
+
+	// Publish observability metrics that we've received notifications
+	s.pushObservabilityMetricFn(GenerateReceivedMetric(len(notificationEvents)))
+
+	for _, event := range notificationEvents {
+		ctx = logging.WithLogrusField(ctx, "notificationID", event.ID)
+		switch strings.ToLower(event.Type) {
+		case "bridge_modal":
+			{
+				// We currently don't support any notification types with bitfields in the body.
+				if isBodyBitfieldValid(event) {
+					continue
+				}
+
+				shouldSend := s.store.shouldSendAndStore(event)
+				if !shouldSend {
+					s.log.Info("Skipping notification event. Notification was displayed previously")
+					continue
+				}
+
+				s.log.Info("Publishing notification event. notificationID:", event.ID) // \todo BRIDGE-141 - change this to UID once it is available
+				s.eventPublisher.PublishEvent(ctx, events.UserNotification{UserID: s.userID, Title: event.Payload.Title,
+					Subtitle: event.Payload.Subtitle, Body: event.Payload.Body})
+
+				// Publish observability metric that we've successfully processed notifications
+				s.pushObservabilityMetricFn(GenerateProcessedMetric(1))
+			}
+
+		default:
+			s.log.Debug("Skipping notification event. Notification type is not related to bridge:", event.Type)
+			continue
+		}
+	}
+	return nil
+}
+
+// We will (potentially) encode different notification functionalities based on a starting bitfield "\NUMBER" in the
+// payload Body. Currently, we don't support this, but we might in the future. This is so versions of Bridge that don't
+// support this functionality won't be display such a message.
+func isBodyBitfieldValid(notification proton.NotificationEvent) bool {
+	match, err := regexp.MatchString(bitfieldRegexPattern, notification.Payload.Body)
+	if err != nil {
+		return false
+	}
+	return match
+}

internal/services/notifications/store.go

@@ -0,0 +1,161 @@
+// Copyright (c) 2024 Proton AG
+//
+// This file is part of Proton Mail Bridge.
+//
+// Proton Mail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Proton Mail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Proton Mail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
+package notifications
+
+import (
+	"crypto"
+	"encoding/hex"
+	"encoding/json"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+
+	"github.com/ProtonMail/go-proton-api"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/exp/maps"
+)
+
+// not-const so we can unit test the functionality.
+var timeOffset = 24 * time.Hour //nolint:gochecknoglobals
+const filename = "notification_cache"
+
+type Store struct {
+	displayedMessages     map[string]time.Time
+	displayedMessagesLock sync.Mutex
+
+	useCache      bool
+	cacheFilepath string
+	cacheLock     sync.Mutex
+
+	log *logrus.Entry
+}
+
+func NewStore(getCachePath func() (string, error)) *Store {
+	log := logrus.WithField("pkg", "notification-store")
+
+	useCacheFile := true
+	cachePath, err := getCachePath()
+	if err != nil {
+		useCacheFile = false
+		log.WithError(err).Error("Could not obtain cache directory")
+	}
+
+	store := &Store{
+		displayedMessages: make(map[string]time.Time),
+
+		useCache:      useCacheFile,
+		cacheFilepath: filepath.Clean(filepath.Join(cachePath, filename)),
+
+		log: log,
+	}
+
+	store.readCache()
+
+	return store
+}
+
+func generateHash(payload proton.NotificationPayload) string {
+	hash := crypto.SHA256.New()
+	hash.Write([]byte(payload.Body + payload.Subtitle + payload.Title))
+	return hex.EncodeToString(hash.Sum(nil))
+}
+
+func (s *Store) shouldSendAndStore(notification proton.NotificationEvent) bool {
+	s.displayedMessagesLock.Lock()
+	defer s.displayedMessagesLock.Unlock()
+
+	// \todo BRIDGE-141 - Add an additional check for the API returned UID
+	uid := generateHash(notification.Payload)
+
+	value, ok := s.displayedMessages[uid]
+	if !ok {
+		s.displayedMessages[uid] = time.Unix(notification.Time, 0).Add(timeOffset)
+		s.writeCache()
+		return true
+	}
+
+	if !time.Now().After(value) {
+		return false
+	}
+
+	s.displayedMessages[uid] = time.Unix(notification.Time, 0).Add(timeOffset)
+	s.writeCache()
+	return true
+}
+
+func (s *Store) readCache() {
+	if !s.useCache {
+		return
+	}
+
+	s.cacheLock.Lock()
+	defer s.cacheLock.Unlock()
+
+	file, err := os.Open(s.cacheFilepath)
+	if err != nil {
+		s.log.WithError(err).Error("Unable to open cache file")
+		return
+	}
+
+	defer func(file *os.File) {
+		err := file.Close()
+		if err != nil {
+			s.log.WithError(err).Error("Unable to close cache file after read")
+		}
+	}(file)
+
+	s.displayedMessagesLock.Lock()
+	defer s.displayedMessagesLock.Unlock()
+	if err = json.NewDecoder(file).Decode(&s.displayedMessages); err != nil {
+		s.log.WithError(err).Error("Unable to decode cache file")
+	}
+
+	// Remove redundant data
+	curTime := time.Now()
+	maps.DeleteFunc(s.displayedMessages, func(_ string, value time.Time) bool {
+		return curTime.After(value)
+	})
+}
+
+func (s *Store) writeCache() {
+	if !s.useCache {
+		return
+	}
+
+	s.cacheLock.Lock()
+	defer s.cacheLock.Unlock()
+
+	file, err := os.Create(s.cacheFilepath)
+	if err != nil {
+		s.log.WithError(err).Info("Unable to create cache file.")
+		return
+	}
+
+	defer func(file *os.File) {
+		err := file.Close()
+		if err != nil {
+			s.log.WithError(err).Error("Unable to close cache file after write")
+		}
+	}(file)
+
+	// We don't lock the mutex here as the parent does that already
+	if err = json.NewEncoder(file).Encode(s.displayedMessages); err != nil {
+		s.log.WithError(err).Error("Unable to encode data to cache file")
+	}
+}

internal/services/observability/service.go

@@ -36,6 +36,8 @@ const (
 	maxBatchSize   = 1000
 )
 
+type PushObsMetricFn func(metric proton.ObservabilityMetric)
+
 type client struct {
 	isTelemetryEnabled func(context.Context) bool
 	sendMetrics        func(context.Context, proton.ObservabilityBatch) error

internal/services/userevents/subscription.go

@@ -38,6 +38,7 @@ type EventHandler struct {
 	MessageHandler      MessageEventHandler
 	UsedSpaceHandler    UserUsedSpaceEventHandler
 	UserSettingsHandler UserSettingsHandler
+	NotificationHandler NotificationEventHandler
 }
 
 func (e EventHandler) OnEvent(ctx context.Context, event proton.Event) error {
@@ -87,6 +88,12 @@ func (e EventHandler) OnEvent(ctx context.Context, event proton.Event) error {
 		}
 	}
 
+	if len(event.Notifications) != 0 && e.NotificationHandler != nil {
+		if err := e.NotificationHandler.HandleNotificationEvents(ctx, event.Notifications); err != nil {
+			return fmt.Errorf("failed to apply notification events: %w", err)
+		}
+	}
+
 	return nil
 }
 
@@ -116,3 +123,7 @@ type LabelEventHandler interface {
 type MessageEventHandler interface {
 	HandleMessageEvents(ctx context.Context, events []proton.MessageEvent) error
 }
+
+type NotificationEventHandler interface {
+	HandleNotificationEvents(ctx context.Context, events []proton.NotificationEvent) error
+}