[MM-41998] Channel Info RHS: display number of files for a channel (#19822)

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

store/opentracinglayer/opentracinglayer.go

@@ -1249,6 +1249,24 @@ func (s *OpenTracingLayerChannelStore) GetDeletedByName(team_id string, name str
 	return result, err
 }
 
+func (s *OpenTracingLayerChannelStore) GetFileCount(channelID string) (int64, error) {
+	origCtx := s.Root.Store.Context()
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.GetFileCount")
+	s.Root.Store.SetContext(newCtx)
+	defer func() {
+		s.Root.Store.SetContext(origCtx)
+	}()
+
+	defer span.Finish()
+	result, err := s.ChannelStore.GetFileCount(channelID)
+	if err != nil {
+		span.LogFields(spanlog.Error(err))
+		ext.Error.Set(span, true)
+	}
+
+	return result, err
+}
+
 func (s *OpenTracingLayerChannelStore) GetForPost(postID string) (*model.Channel, error) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.GetForPost")

store/retrylayer/retrylayer.go

@@ -1402,6 +1402,27 @@ func (s *RetryLayerChannelStore) GetDeletedByName(team_id string, name string) (
 
 }
 
+func (s *RetryLayerChannelStore) GetFileCount(channelID string) (int64, error) {
+
+	tries := 0
+	for {
+		result, err := s.ChannelStore.GetFileCount(channelID)
+		if err == nil {
+			return result, nil
+		}
+		if !isRepeatableError(err) {
+			return result, err
+		}
+		tries++
+		if tries >= 3 {
+			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
+			return result, err
+		}
+		timepkg.Sleep(100 * timepkg.Millisecond)
+	}
+
+}
+
 func (s *RetryLayerChannelStore) GetForPost(postID string) (*model.Channel, error) {
 
 	tries := 0

store/sqlstore/channel_store.go

@@ -2188,6 +2188,25 @@ func (s SqlChannelStore) GetMemberCountFromCache(channelId string) int64 {
 	return count
 }
 
+func (s SqlChannelStore) GetFileCount(channelId string) (int64, error) {
+	var count int64
+	err := s.GetReplicaX().Get(&count, `
+		SELECT
+			COUNT(*)
+		FROM
+			FileInfo
+                LEFT JOIN Posts as P ON FileInfo.PostId=P.Id
+                LEFT JOIN Channels as C on C.Id=P.ChannelId
+		WHERE
+                        FileInfo.DeleteAt = 0
+			AND C.Id = ?`, channelId)
+	if err != nil {
+		return 0, errors.Wrapf(err, "failed to count files with channelId=%s", channelId)
+	}
+
+	return count, nil
+}
+
 //nolint:unparam
 func (s SqlChannelStore) GetMemberCount(channelId string, allowFromCache bool) (int64, error) {
 	var count int64

store/store.go

@@ -213,6 +213,7 @@ type ChannelStore interface {
 	GetMemberForPost(postID string, userID string) (*model.ChannelMember, error)
 	InvalidateMemberCount(channelID string)
 	GetMemberCountFromCache(channelID string) int64
+	GetFileCount(channelID string) (int64, error)
 	GetMemberCount(channelID string, allowFromCache bool) (int64, error)
 	GetMemberCountsByGroup(ctx context.Context, channelID string, includeTimezones bool) ([]*model.ChannelMemberCountByGroup, error)
 	InvalidatePinnedPostCount(channelID string)

store/storetest/mocks/ChannelStore.go

@@ -881,6 +881,27 @@ func (_m *ChannelStore) GetDeletedByName(team_id string, name string) (*model.Ch
 	return r0, r1
 }
 
+// GetFileCount provides a mock function with given fields: channelID
+func (_m *ChannelStore) GetFileCount(channelID string) (int64, error) {
+	ret := _m.Called(channelID)
+
+	var r0 int64
+	if rf, ok := ret.Get(0).(func(string) int64); ok {
+		r0 = rf(channelID)
+	} else {
+		r0 = ret.Get(0).(int64)
+	}
+
+	var r1 error
+	if rf, ok := ret.Get(1).(func(string) error); ok {
+		r1 = rf(channelID)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // GetForPost provides a mock function with given fields: postID
 func (_m *ChannelStore) GetForPost(postID string) (*model.Channel, error) {
 	ret := _m.Called(postID)

store/timerlayer/timerlayer.go

@@ -1157,6 +1157,22 @@ func (s *TimerLayerChannelStore) GetDeletedByName(team_id string, name string) (
 	return result, err
 }
 
+func (s *TimerLayerChannelStore) GetFileCount(channelID string) (int64, error) {
+	start := timemodule.Now()
+
+	result, err := s.ChannelStore.GetFileCount(channelID)
+
+	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.GetFileCount", success, elapsed)
+	}
+	return result, err
+}
+
 func (s *TimerLayerChannelStore) GetForPost(postID string) (*model.Channel, error) {
 	start := timemodule.Now()