feat(BUX-567): track metrics of cronJobs

cron_job_declarations.go

@@ -19,33 +19,50 @@ type cronJobHandler func(ctx context.Context, client *Client) error
 
 // here is where we define all the cron jobs for the client
 func (c *Client) cronJobs() taskmanager.CronJobs {
-	// handler adds the client pointer to the cronJobTask by using a closure
-	handler := func(cronJobTask cronJobHandler) taskmanager.CronJobHandler {
-		return func(ctx context.Context) error {
-			return cronJobTask(ctx, c)
+	jobs := taskmanager.CronJobs{}
+
+	addJob := func(name string, period time.Duration, task cronJobHandler) {
+		// handler adds the client pointer to the cronJobTask by using a closure
+		handler := func(ctx context.Context) (err error) {
+			if metrics, enabled := c.Metrics(); enabled {
+				end := metrics.TrackCron(name)
+				defer func() {
+					success := err == nil
+					end(success)
+				}()
+			}
+			err = task(ctx, c)
+			return
 		}
-	}
 
-	jobs := taskmanager.CronJobs{
-		CronJobNameDraftTransactionCleanUp: {
-			Period:  60 * time.Second,
-			Handler: handler(taskCleanupDraftTransactions),
-		},
-		CronJobNameSyncTransactionBroadcast: {
-			Period:  2 * time.Minute,
-			Handler: handler(taskBroadcastTransactions),
-		},
-		CronJobNameSyncTransactionSync: {
-			Period:  5 * time.Minute,
-			Handler: handler(taskSyncTransactions),
-		},
+		jobs[name] = taskmanager.CronJob{
+			Handler: handler,
+			Period:  period,
+		}
 	}
 
+	addJob(
+		CronJobNameDraftTransactionCleanUp,
+		60*time.Second,
+		taskCleanupDraftTransactions,
+	)
+	addJob(
+		CronJobNameSyncTransactionBroadcast,
+		2*time.Minute,
+		taskBroadcastTransactions,
+	)
+	addJob(
+		CronJobNameSyncTransactionSync,
+		5*time.Minute,
+		taskSyncTransactions,
+	)
+
 	if _, enabled := c.Metrics(); enabled {
-		jobs[CronJobNameCalculateMetrics] = taskmanager.CronJob{
-			Period:  15 * time.Second,
-			Handler: handler(taskCalculateMetrics),
-		}
+		addJob(
+			CronJobNameCalculateMetrics,
+			15*time.Second,
+			taskCalculateMetrics,
+		)
 	}
 
 	return jobs

metrics/interface.go

@@ -3,9 +3,14 @@ package metrics
 // Collector is an interface that is used to register metrics
 type Collector interface {
 	RegisterGauge(name string) GaugeInterface
+	RegisterGaugeVec(name string, labels ...string) GaugeVecInterface
 	RegisterHistogramVec(name string, labels ...string) HistogramVecInterface
 }
 
+type GaugeVecInterface interface {
+	WithLabelValues(lvs ...string) GaugeInterface
+}
+
 // GaugeInterface is an interface that is used to track gauges of values
 type GaugeInterface interface {
 	Set(value float64)

metrics/metrics.go

@@ -12,6 +12,8 @@ type Metrics struct {
 	verifyMerkleRoots HistogramVecInterface
 	recordTransaction HistogramVecInterface
 	queryTransaction  HistogramVecInterface
+	cronHistogram     HistogramVecInterface
+	cronLastExecution GaugeVecInterface
 }
 
 // NewMetrics is a constructor for the Metrics struct
@@ -22,6 +24,8 @@ func NewMetrics(collector Collector) *Metrics {
 		verifyMerkleRoots: collector.RegisterHistogramVec(verifyMerkleRootsHistogramName, "classification"),
 		recordTransaction: collector.RegisterHistogramVec(recordTransactionHistogramName, "classification", "strategy"),
 		queryTransaction:  collector.RegisterHistogramVec(queryTransactionHistogramName, "classification"),
+		cronHistogram:     collector.RegisterHistogramVec(cronHistogramName, "name"),
+		cronLastExecution: collector.RegisterGaugeVec(cronLastExecutionGaugeName, "name"),
 	}
 }
 
@@ -52,6 +56,15 @@ func (m *Metrics) TrackQueryTransaction() EndWithClassification {
 	}
 }
 
+// TrackCron is used to track the time it takes to execute a cron job
+func (m *Metrics) TrackCron(name string) EndWithClassification {
+	start := time.Now()
+	m.cronLastExecution.WithLabelValues(name).Set(float64(start.Unix()))
+	return func(success bool) {
+		m.cronHistogram.WithLabelValues(name).Observe(time.Since(start).Seconds())
+	}
+}
+
 func classify(success bool) string {
 	if success {
 		return "success"

metrics/naming.go

@@ -8,4 +8,9 @@ const (
 	queryTransactionHistogramName  = domainPrefix + "query_transaction_histogram"
 )
 
+const (
+	cronHistogramName          = domainPrefix + "cron_histogram"
+	cronLastExecutionGaugeName = domainPrefix + "cron_last_execution_gauge"
+)
+
 const xpubGaugeName = domainPrefix + "xpub_gauge"