Track last scraped time per metric

collector/collector.go

@@ -91,8 +91,10 @@ func NewExporter(logger *slog.Logger, cfg *Config) (*Exporter, error) {
 			Name:      "dbtype",
 			Help:      "Type of database the exporter is connected to (0=non-CDB, 1=CDB, >1=PDB).",
 		}),
-		logger: logger,
-		config: cfg,
+		logger:         logger,
+		config:         cfg,
+		lastScraped:    map[string]*time.Time{},
+		scrapeInterval: cfg.ScrapeInterval,
 	}
 	e.metricsToScrape = e.DefaultMetrics()
 	err := e.connect()
@@ -131,7 +133,7 @@ func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
 func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 	// they are running scheduled scrapes we should only scrape new data
 	// on the interval
-	if e.scrapeInterval != nil && *e.scrapeInterval != 0 {
+	if e.scrapeInterval != 0 {
 		// read access must be checked
 		e.mu.Lock()
 		for _, r := range e.scrapeResults {
@@ -155,12 +157,10 @@ func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
 
 // RunScheduledScrapes is only relevant for users of this package that want to set the scrape on a timer
 // rather than letting it be per Collect call
-func (e *Exporter) RunScheduledScrapes(ctx context.Context, si time.Duration) {
-	e.scrapeInterval = &si
-
+func (e *Exporter) RunScheduledScrapes(ctx context.Context) {
 	e.doScrape(time.Now())
 
-	ticker := time.NewTicker(si)
+	ticker := time.NewTicker(e.scrapeInterval)
 	defer ticker.Stop()
 
 	for {
@@ -177,7 +177,6 @@ func (e *Exporter) RunScheduledScrapes(ctx context.Context, si time.Duration) {
 func (e *Exporter) doScrape(tick time.Time) {
 	e.mu.Lock() // ensure no simultaneous scrapes
 	e.scheduledScrape(&tick)
-	e.lastTick = &tick
 	e.mu.Unlock()
 }
 
@@ -246,7 +245,9 @@ func (e *Exporter) scrape(ch chan<- prometheus.Metric, tick *time.Time) {
 
 	for _, metric := range e.metricsToScrape.Metric {
 		metric := metric //https://golang.org/doc/faq#closures_and_goroutines
-
+		if !e.isScrapeMetric(tick, metric) {
+			continue
+		}
 		go func() {
 			e.logger.Debug("About to scrape metric",
 				"Context", metric.Context,
@@ -476,13 +477,10 @@ func (e *Exporter) reloadMetrics() {
 // ScrapeMetric is an interface method to call scrapeGenericValues using Metric struct values
 func (e *Exporter) ScrapeMetric(db *sql.DB, ch chan<- prometheus.Metric, m Metric, tick *time.Time) error {
 	e.logger.Debug("Calling function ScrapeGenericValues()")
-	if e.isScrapeMetric(tick, m) {
-		queryTimeout := e.getQueryTimeout(m)
-		return e.scrapeGenericValues(db, ch, m.Context, m.Labels, m.MetricsDesc,
-			m.MetricsType, m.MetricsBuckets, m.FieldToAppend, m.IgnoreZeroResult,
-			m.Request, queryTimeout)
-	}
-	return nil
+	queryTimeout := e.getQueryTimeout(m)
+	return e.scrapeGenericValues(db, ch, m.Context, m.Labels, m.MetricsDesc,
+		m.MetricsType, m.MetricsBuckets, m.FieldToAppend, m.IgnoreZeroResult,
+		m.Request, queryTimeout)
 }
 
 // generic method for retrieving metrics.

collector/metrics.go

@@ -13,18 +13,25 @@ import (
 // and the time since the last scrape is less than the custom scrape interval.
 // If there is no tick time or last known tick, the metric is always scraped.
 func (e *Exporter) isScrapeMetric(tick *time.Time, metric Metric) bool {
-	// Always scrape the metric if we don't have a current or last known tick.
-	if tick == nil || e.lastTick == nil {
+	// Always scrape the metric if we don't have a current tick.
+	if tick == nil {
 		return true
 	}
 	// If the metric doesn't have a custom scrape interval, scrape it.
 	interval, ok := e.getScrapeInterval(metric.Context, metric.ScrapeInterval)
 	if !ok {
 		return true
 	}
-	// If the metric's scrape interval is less than the time elapsed since the last scrape,
-	// we should scrape the metric.
-	return interval < tick.Sub(*e.lastTick)
+	id := metric.id()
+	lastScraped := e.lastScraped[id]
+	shouldScrape := lastScraped == nil ||
+		// If the metric's scrape interval is less than the time elapsed since the last scrape,
+		// we should scrape the metric.
+		interval < tick.Sub(*lastScraped)
+	if shouldScrape {
+		e.lastScraped[id] = tick
+	}
+	return shouldScrape
 }
 
 func (e *Exporter) getScrapeInterval(context, scrapeInterval string) (time.Duration, bool) {

collector/types.go

@@ -7,6 +7,7 @@ import (
 	"github.com/godror/godror/dsn"
 	"github.com/prometheus/client_golang/prometheus"
 	"log/slog"
+	"strings"
 	"sync"
 	"time"
 )
@@ -16,7 +17,7 @@ type Exporter struct {
 	config          *Config
 	mu              *sync.Mutex
 	metricsToScrape Metrics
-	scrapeInterval  *time.Duration
+	scrapeInterval  time.Duration
 	user            string
 	password        string
 	connectString   string
@@ -31,7 +32,7 @@ type Exporter struct {
 	dbtypeGauge     prometheus.Gauge
 	db              *sql.DB
 	logger          *slog.Logger
-	lastTick        *time.Time
+	lastScraped     map[string]*time.Time
 }
 
 type Config struct {
@@ -49,6 +50,7 @@ type Config struct {
 	CustomMetrics      string
 	QueryTimeout       int
 	DefaultMetricsFile string
+	ScrapeInterval     time.Duration
 }
 
 // Metric is an object description
@@ -69,3 +71,12 @@ type Metric struct {
 type Metrics struct {
 	Metric []Metric
 }
+
+func (m Metric) id() string {
+	builder := strings.Builder{}
+	builder.WriteString(m.Context)
+	for _, d := range m.MetricsDesc {
+		builder.WriteString(d)
+	}
+	return builder.String()
+}

main.go

@@ -120,6 +120,7 @@ func main() {
 		CustomMetrics:      *customMetrics,
 		QueryTimeout:       *queryTimeout,
 		DefaultMetricsFile: *defaultFileMetrics,
+		ScrapeInterval:     *scrapeInterval,
 	}
 	exporter, err := collector.NewExporter(logger, config)
 	if err != nil {
@@ -129,7 +130,7 @@ func main() {
 	if *scrapeInterval != 0 {
 		ctx, cancel := context.WithCancel(context.Background())
 		defer cancel()
-		go exporter.RunScheduledScrapes(ctx, *scrapeInterval)
+		go exporter.RunScheduledScrapes(ctx)
 	}
 
 	prometheus.MustRegister(exporter)