feat(config): add `SCHEDULER_ROUND_ROBIN_MAX_INTERVAL` option

Add option to cap maximum refresh interval when RSS TTL, Retry-After, Cache-Control, or Expires headers specify excessively high values.

internal/config/config_test.go

@@ -1028,6 +1028,41 @@ func TestSchedulerRoundRobin(t *testing.T) {
 	}
 }
 
+func TestDefaultSchedulerRoundRobinMaxIntervalValue(t *testing.T) {
+	os.Clearenv()
+
+	parser := NewParser()
+	opts, err := parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+
+	expected := defaultSchedulerRoundRobinMaxInterval
+	result := opts.SchedulerRoundRobinMaxInterval()
+
+	if result != expected {
+		t.Fatalf(`Unexpected SCHEDULER_ROUND_ROBIN_MAX_INTERVAL value, got %v instead of %v`, result, expected)
+	}
+}
+
+func TestSchedulerRoundRobinMaxInterval(t *testing.T) {
+	os.Clearenv()
+	os.Setenv("SCHEDULER_ROUND_ROBIN_MAX_INTERVAL", "150")
+
+	parser := NewParser()
+	opts, err := parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+
+	expected := 150
+	result := opts.SchedulerRoundRobinMaxInterval()
+
+	if result != expected {
+		t.Fatalf(`Unexpected SCHEDULER_ROUND_ROBIN_MAX_INTERVAL value, got %v instead of %v`, result, expected)
+	}
+}
+
 func TestPollingParsingErrorLimit(t *testing.T) {
 	os.Clearenv()
 	os.Setenv("POLLING_PARSING_ERROR_LIMIT", "100")

internal/config/options.go

@@ -37,6 +37,7 @@ const (
 	defaultSchedulerEntryFrequencyMaxInterval = 24 * 60
 	defaultSchedulerEntryFrequencyFactor      = 1
 	defaultSchedulerRoundRobinMinInterval     = 60
+	defaultSchedulerRoundRobinMaxInterval     = 1440
 	defaultPollingParsingErrorLimit           = 3
 	defaultRunMigrations                      = false
 	defaultDatabaseURL                        = "user=postgres password=postgres dbname=miniflux2 sslmode=disable"
@@ -137,6 +138,7 @@ type Options struct {
 	schedulerEntryFrequencyMaxInterval int
 	schedulerEntryFrequencyFactor      int
 	schedulerRoundRobinMinInterval     int
+	schedulerRoundRobinMaxInterval     int
 	pollingParsingErrorLimit           int
 	workerPoolSize                     int
 	createAdmin                        bool
@@ -220,6 +222,7 @@ func NewOptions() *Options {
 		schedulerEntryFrequencyMaxInterval: defaultSchedulerEntryFrequencyMaxInterval,
 		schedulerEntryFrequencyFactor:      defaultSchedulerEntryFrequencyFactor,
 		schedulerRoundRobinMinInterval:     defaultSchedulerRoundRobinMinInterval,
+		schedulerRoundRobinMaxInterval:     defaultSchedulerRoundRobinMaxInterval,
 		pollingParsingErrorLimit:           defaultPollingParsingErrorLimit,
 		workerPoolSize:                     defaultWorkerPoolSize,
 		createAdmin:                        defaultCreateAdmin,
@@ -433,6 +436,10 @@ func (o *Options) SchedulerRoundRobinMinInterval() int {
 	return o.schedulerRoundRobinMinInterval
 }
 
+func (o *Options) SchedulerRoundRobinMaxInterval() int {
+	return o.schedulerRoundRobinMaxInterval
+}
+
 // PollingParsingErrorLimit returns the limit of errors when to stop polling.
 func (o *Options) PollingParsingErrorLimit() int {
 	return o.pollingParsingErrorLimit
@@ -778,6 +785,7 @@ func (o *Options) SortedOptions(redactSecret bool) []*Option {
 		"SCHEDULER_ENTRY_FREQUENCY_MIN_INTERVAL": o.schedulerEntryFrequencyMinInterval,
 		"SCHEDULER_ENTRY_FREQUENCY_FACTOR":       o.schedulerEntryFrequencyFactor,
 		"SCHEDULER_ROUND_ROBIN_MIN_INTERVAL":     o.schedulerRoundRobinMinInterval,
+		"SCHEDULER_ROUND_ROBIN_MAX_INTERVAL":     o.schedulerRoundRobinMaxInterval,
 		"SCHEDULER_SERVICE":                      o.schedulerService,
 		"SERVER_TIMING_HEADER":                   o.serverTimingHeader,
 		"WATCHDOG":                               o.watchdog,

internal/config/parser.go

@@ -160,6 +160,8 @@ func (p *Parser) parseLines(lines []string) (err error) {
 			p.opts.schedulerEntryFrequencyFactor = parseInt(value, defaultSchedulerEntryFrequencyFactor)
 		case "SCHEDULER_ROUND_ROBIN_MIN_INTERVAL":
 			p.opts.schedulerRoundRobinMinInterval = parseInt(value, defaultSchedulerRoundRobinMinInterval)
+		case "SCHEDULER_ROUND_ROBIN_MAX_INTERVAL":
+			p.opts.schedulerRoundRobinMaxInterval = parseInt(value, defaultSchedulerRoundRobinMaxInterval)
 		case "POLLING_PARSING_ERROR_LIMIT":
 			p.opts.pollingParsingErrorLimit = parseInt(value, defaultPollingParsingErrorLimit)
 		case "PROXY_IMAGES":

internal/model/feed.go

@@ -117,9 +117,7 @@ func (f *Feed) CheckedNow() {
 }
 
 // ScheduleNextCheck set "next_check_at" of a feed based on the scheduler selected from the configuration.
-func (f *Feed) ScheduleNextCheck(weeklyCount int, refreshDelayInMinutes int) {
-	f.TTL = refreshDelayInMinutes
-
+func (f *Feed) ScheduleNextCheck(weeklyCount int, refreshDelayInMinutes int) int {
 	// Default to the global config Polling Frequency.
 	intervalMinutes := config.Opts.SchedulerRoundRobinMinInterval()
 
@@ -133,12 +131,21 @@ func (f *Feed) ScheduleNextCheck(weeklyCount int, refreshDelayInMinutes int) {
 		}
 	}
 
-	// If the feed has a TTL or a Retry-After defined, we use it to make sure we don't check it too often.
+	// Use the RSS TTL field, Retry-After, Cache-Control or Expires HTTP headers if defined.
 	if refreshDelayInMinutes > 0 && refreshDelayInMinutes > intervalMinutes {
 		intervalMinutes = refreshDelayInMinutes
 	}
 
+	// Limit the max interval value for misconfigured feeds.
+	switch config.Opts.PollingScheduler() {
+	case SchedulerRoundRobin:
+		intervalMinutes = min(intervalMinutes, config.Opts.SchedulerRoundRobinMaxInterval())
+	case SchedulerEntryFrequency:
+		intervalMinutes = min(intervalMinutes, config.Opts.SchedulerEntryFrequencyMaxInterval())
+	}
+
 	f.NextCheckAt = time.Now().Add(time.Minute * time.Duration(intervalMinutes))
+	return intervalMinutes
 }
 
 // FeedCreationRequest represents the request to create a feed.

internal/model/feed_test.go

@@ -144,6 +144,29 @@ func TestFeedScheduleNextCheckRoundRobinWithRefreshDelayBelowMinInterval(t *test
 	checkTargetInterval(t, feed, expectedInterval, timeBefore, "TestFeedScheduleNextCheckRoundRobinWithRefreshDelayBelowMinInterval")
 }
 
+func TestFeedScheduleNextCheckRoundRobinWithRefreshDelayAboveMaxInterval(t *testing.T) {
+	os.Clearenv()
+
+	var err error
+	parser := config.NewParser()
+	config.Opts, err = parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+
+	timeBefore := time.Now()
+	feed := &Feed{}
+
+	feed.ScheduleNextCheck(0, config.Opts.SchedulerRoundRobinMaxInterval()+30)
+
+	if feed.NextCheckAt.IsZero() {
+		t.Error(`The next_check_at must be set`)
+	}
+
+	expectedInterval := config.Opts.SchedulerRoundRobinMaxInterval()
+	checkTargetInterval(t, feed, expectedInterval, timeBefore, "TestFeedScheduleNextCheckRoundRobinWithRefreshDelayAboveMaxInterval")
+}
+
 func TestFeedScheduleNextCheckRoundRobinMinInterval(t *testing.T) {
 	minInterval := 1
 	os.Clearenv()

internal/reader/handler/handler.go

@@ -240,12 +240,13 @@ func RefreshFeed(store *storage.Storage, userID, feedID int64, forceRefresh bool
 	if responseHandler.IsRateLimited() {
 		retryDelayInSeconds := responseHandler.ParseRetryDelay()
 		refreshDelayInMinutes = retryDelayInSeconds / 60
-		originalFeed.ScheduleNextCheck(weeklyEntryCount, refreshDelayInMinutes)
+		calculatedNextCheckIntervalInMinutes := originalFeed.ScheduleNextCheck(weeklyEntryCount, refreshDelayInMinutes)
 
 		slog.Warn("Feed is rate limited",
 			slog.String("feed_url", originalFeed.FeedURL),
 			slog.Int("retry_delay_in_seconds", retryDelayInSeconds),
 			slog.Int("refresh_delay_in_minutes", refreshDelayInMinutes),
+			slog.Int("calculated_next_check_interval_in_minutes", calculatedNextCheckIntervalInMinutes),
 			slog.Time("new_next_check_at", originalFeed.NextCheckAt),
 		)
 	}
@@ -316,7 +317,7 @@ func RefreshFeed(store *storage.Storage, userID, feedID int64, forceRefresh bool
 		refreshDelayInMinutes = max(feedTTLValue, cacheControlMaxAgeValue, expiresValue)
 
 		// Set the next check at with updated arguments.
-		originalFeed.ScheduleNextCheck(weeklyEntryCount, refreshDelayInMinutes)
+		calculatedNextCheckIntervalInMinutes := originalFeed.ScheduleNextCheck(weeklyEntryCount, refreshDelayInMinutes)
 
 		slog.Debug("Updated next check date",
 			slog.Int64("user_id", userID),
@@ -326,6 +327,7 @@ func RefreshFeed(store *storage.Storage, userID, feedID int64, forceRefresh bool
 			slog.Int("cache_control_max_age_in_minutes", cacheControlMaxAgeValue),
 			slog.Int("expires_in_minutes", expiresValue),
 			slog.Int("refresh_delay_in_minutes", refreshDelayInMinutes),
+			slog.Int("calculated_next_check_interval_in_minutes", calculatedNextCheckIntervalInMinutes),
 			slog.Time("new_next_check_at", originalFeed.NextCheckAt),
 		)
 

miniflux.1

@@ -1,5 +1,5 @@
 .\" Manpage for miniflux.
-.TH "MINIFLUX" "1" "December 7, 2024" "\ \&" "\ \&"
+.TH "MINIFLUX" "1" "April 11, 2025" "\ \&" "\ \&"
 
 .SH NAME
 miniflux \- Minimalist and opinionated feed reader
@@ -533,6 +533,11 @@ Minimum interval in minutes for the entry frequency scheduler\&.
 .br
 Default is 5 minutes\&.
 .TP
+.B SCHEDULER_ROUND_ROBIN_MAX_INTERVAL
+Maximum interval in minutes for the round robin scheduler\&.
+.br
+Default is 1440 minutes (24 hours)\&.
+.TP
 .B SCHEDULER_ROUND_ROBIN_MIN_INTERVAL
 Minimum interval in minutes for the round robin scheduler\&.
 .br