refactor(metric): use time.Duration for refresh duration

internal/config/config_test.go

@@ -2230,3 +2230,58 @@ func TestCustomPollingLimitPerHost(t *testing.T) {
 		t.Fatalf(`Unexpected custom PollingLimitPerHost value, got %v instead of %v`, result, expected)
 	}
 }
+
+func TestMetricsRefreshInterval(t *testing.T) {
+	os.Clearenv()
+	os.Setenv("METRICS_REFRESH_INTERVAL", "33")
+
+	parser := NewParser()
+	opts, err := parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+
+	expected := 33 * time.Second
+	result := opts.MetricsRefreshInterval()
+
+	if result != expected {
+		t.Fatalf(`Unexpected METRICS_REFRESH_INTERVAL value, got %d instead of %d`, result, expected)
+	}
+
+	sorted := opts.SortedOptions(false)
+	i := slices.IndexFunc(sorted, func(opt *option) bool {
+		return opt.Key == "METRICS_REFRESH_INTERVAL"
+	})
+
+	expectedSerialized := 33
+	if got := sorted[i].Value; got != expectedSerialized {
+		t.Fatalf(`Unexpected value in option output, got %q instead of %q`, got, expectedSerialized)
+	}
+}
+
+func TestDefaultMetricsRefreshInterval(t *testing.T) {
+	os.Clearenv()
+
+	parser := NewParser()
+	opts, err := parser.ParseEnvironmentVariables()
+	if err != nil {
+		t.Fatalf(`Parsing failure: %v`, err)
+	}
+
+	expected := defaultMetricsRefreshInterval
+	result := opts.MetricsRefreshInterval()
+
+	if result != expected {
+		t.Fatalf(`Unexpected METRICS_REFRESH_INTERVAL value, got %d instead of %d`, result, expected)
+	}
+
+	sorted := opts.SortedOptions(false)
+	i := slices.IndexFunc(sorted, func(opt *option) bool {
+		return opt.Key == "METRICS_REFRESH_INTERVAL"
+	})
+
+	expectedSerialized := int(defaultMetricsRefreshInterval / time.Second)
+	if got := sorted[i].Value; got != expectedSerialized {
+		t.Fatalf(`Unexpected value in option output, got %q instead of %q`, got, expectedSerialized)
+	}
+}

internal/config/options.go

@@ -83,7 +83,7 @@ const (
 	defaultMaintenanceMode                    = false
 	defaultMaintenanceMessage                 = "Miniflux is currently under maintenance"
 	defaultMetricsCollector                   = false
-	defaultMetricsRefreshInterval             = 60
+	defaultMetricsRefreshInterval             = 60 * time.Second
 	defaultMetricsAllowedNetworks             = "127.0.0.1/8"
 	defaultMetricsUsername                    = ""
 	defaultMetricsPassword                    = ""
@@ -176,7 +176,7 @@ type options struct {
 	maintenanceMode                    bool
 	maintenanceMessage                 string
 	metricsCollector                   bool
-	metricsRefreshInterval             int
+	metricsRefreshInterval             time.Duration
 	metricsAllowedNetworks             []string
 	metricsUsername                    string
 	metricsPassword                    string
@@ -639,8 +639,8 @@ func (o *options) HasMetricsCollector() bool {
 	return o.metricsCollector
 }
 
-// MetricsRefreshInterval returns the refresh interval in seconds.
+// MetricsRefreshInterval returns the refresh interval.
-func (o *options) MetricsRefreshInterval() int {
+func (o *options) MetricsRefreshInterval() time.Duration {
 	return o.metricsRefreshInterval
 }
 
@@ -759,7 +759,7 @@ func (o *options) SortedOptions(redactSecret bool) []*option {
 		"METRICS_ALLOWED_NETWORKS":               strings.Join(o.metricsAllowedNetworks, ","),
 		"METRICS_COLLECTOR":                      o.metricsCollector,
 		"METRICS_PASSWORD":                       redactSecretValue(o.metricsPassword, redactSecret),
-		"METRICS_REFRESH_INTERVAL":               o.metricsRefreshInterval,
+		"METRICS_REFRESH_INTERVAL":               int(o.metricsRefreshInterval.Seconds()),
 		"METRICS_USERNAME":                       o.metricsUsername,
 		"OAUTH2_CLIENT_ID":                       o.oauth2ClientID,
 		"OAUTH2_CLIENT_SECRET":                   redactSecretValue(o.oauth2ClientSecret, redactSecret),

internal/config/parser.go

@@ -231,7 +231,7 @@ func (p *parser) parseLines(lines []string) (err error) {
 		case "METRICS_COLLECTOR":
 			p.opts.metricsCollector = parseBool(value, defaultMetricsCollector)
 		case "METRICS_REFRESH_INTERVAL":
-			p.opts.metricsRefreshInterval = parseInt(value, defaultMetricsRefreshInterval)
+			p.opts.metricsRefreshInterval = parseInterval(value, time.Second, defaultMetricsRefreshInterval)
 		case "METRICS_ALLOWED_NETWORKS":
 			p.opts.metricsAllowedNetworks = parseStringList(value, []string{defaultMetricsAllowedNetworks})
 		case "METRICS_USERNAME":

internal/metric/metric.go

@@ -138,11 +138,11 @@ var (
 // collector represents a metric collector.
 type collector struct {
 	store           *storage.Storage
-	refreshInterval int
+	refreshInterval time.Duration
 }
 
 // NewCollector initializes a new metric collector.
-func NewCollector(store *storage.Storage, refreshInterval int) *collector {
+func NewCollector(store *storage.Storage, refreshInterval time.Duration) *collector {
 	prometheus.MustRegister(BackgroundFeedRefreshDuration)
 	prometheus.MustRegister(ScraperRequestDuration)
 	prometheus.MustRegister(ArchiveEntriesDuration)
@@ -163,7 +163,7 @@ func NewCollector(store *storage.Storage, refreshInterval int) *collector {
 
 // GatherStorageMetrics polls the database to fetch metrics.
 func (c *collector) GatherStorageMetrics() {
-	for range time.Tick(time.Duration(c.refreshInterval) * time.Second) {
+	for range time.Tick(c.refreshInterval) {
 		slog.Debug("Collecting metrics from the database")
 
 		usersGauge.Set(float64(c.store.CountUsers()))