add some metrics

aggregate.go

@@ -78,6 +78,13 @@ func (ao *aggregateOptions) formatIgnoredLabels() {
 	sort.Strings(ao.ignoredLabels)
 }
 
+func (a *aggregate) Len() int {
+	a.familiesLock.RLock()
+	count := len(a.families)
+	a.familiesLock.RUnlock()
+	return count
+}
+
 // setFamilyOrGetExistingFamily either sets a new family or returns an existing family
 func (a *aggregate) setFamilyOrGetExistingFamily(familyName string, family *dto.MetricFamily) *metricFamily {
 	a.familiesLock.Lock()
@@ -126,8 +133,12 @@ func (a *aggregate) parseAndMerge(r io.Reader, job string) error {
 			return err
 		}
 
+		MetricCountByFamily.WithLabelValues(name).Set(float64(len(family.Metric)))
+
 	}
 
+	TotalFamiliesGauge.Set(float64(a.Len()))
+
 	return nil
 }
 
@@ -140,9 +151,18 @@ func (a *aggregate) handleRender(c *gin.Context) {
 	defer a.familiesLock.RUnlock()
 
 	metricNames := []string{}
-	for name := range a.families {
+	metricTypeCounts := make(map[string]int)
+	for name, family := range a.families {
 		metricNames = append(metricNames, name)
+		var typeName string
+		if family.Type == nil {
+			typeName = "unknown"
+		} else {
+			typeName = dto.MetricType_name[int32(*family.Type)]
+		}
+		metricTypeCounts[typeName]++
 	}
+
 	sort.Strings(metricNames)
 
 	for _, name := range metricNames {
@@ -151,6 +171,11 @@ func (a *aggregate) handleRender(c *gin.Context) {
 		}
 	}
 
+	MetricCountByType.Reset()
+	for typeName, count := range metricTypeCounts {
+		MetricCountByType.WithLabelValues(typeName).Set(float64(count))
+	}
+
 	// TODO reset gauges
 }
 
@@ -180,4 +205,6 @@ func (a *aggregate) handleInsert(c *gin.Context) {
 		http.Error(c.Writer, err.Error(), http.StatusBadRequest)
 		return
 	}
+
+	MetricPushes.WithLabelValues(job).Inc()
 }

main.go

@@ -9,7 +9,6 @@ import (
 	"syscall"
 
 	"github.com/gin-gonic/gin"
-	"github.com/prometheus/client_golang/prometheus"
 	metrics "github.com/slok/go-http-metrics/metrics/prometheus"
 )
 
@@ -41,7 +40,6 @@ func runServers(corsDomain string, apiListen string, lifecycleListen string) {
 
 	agg := newAggregate()
 
-	promRegistry := prometheus.NewRegistry()
 	promMetricsConfig := metrics.Config{
 		Registry: promRegistry,
 	}

metrics.go

@@ -0,0 +1,56 @@
+package main
+
+import "github.com/prometheus/client_golang/prometheus"
+
+const MetricsNamespace = "prom_agg_gateway"
+
+var promRegistry = prometheus.NewRegistry()
+
+func init() {
+	promRegistry.MustRegister(
+		TotalFamiliesGauge,
+		MetricCountByFamily,
+		MetricPushes,
+	)
+}
+
+var TotalFamiliesGauge = prometheus.NewGauge(
+	prometheus.GaugeOpts{
+		Namespace: MetricsNamespace,
+		Name:      "total_families",
+		Help:      "Total number of metric families",
+	},
+)
+
+var MetricCountByFamily = prometheus.NewGaugeVec(
+	prometheus.GaugeOpts{
+		Namespace: MetricsNamespace,
+		Name:      "metrics_by_family",
+		Help:      "Metric count by family",
+	},
+	[]string{
+		"family",
+	},
+)
+
+var MetricCountByType = prometheus.NewGaugeVec(
+	prometheus.GaugeOpts{
+		Namespace: MetricsNamespace,
+		Name: "metrics_by_type",
+		Help: "Metric count by type",
+	},
+	[]string{
+		"metric_type",
+	},
+);
+
+var MetricPushes = prometheus.NewCounterVec(
+	prometheus.CounterOpts{
+		Namespace: MetricsNamespace,
+		Name:      "metric_pushes",
+		Help:      "Total number of metric push requests, per job",
+	},
+	[]string{
+		"push_job",
+	},
+)