dependency-injected non-global metrics object

pkg/config/loader.go

@@ -5,8 +5,6 @@ import (
 	"io/ioutil"
 	"os"
 
-	"github.com/directxman12/k8s-prometheus-adapter/pkg/metrics"
-
 	"gopkg.in/yaml.v2"
 )
 
@@ -30,7 +28,5 @@ func FromYAML(contents []byte) (*MetricsDiscoveryConfig, error) {
 	if err := yaml.UnmarshalStrict(contents, &cfg); err != nil {
 		return nil, fmt.Errorf("unable to parse metrics discovery config: %v", err)
 	}
-	metrics.Rules.WithLabelValues("normal").Set(float64(len(cfg.Rules)))
-	metrics.Rules.WithLabelValues("external").Set(float64(len(cfg.ExternalRules)))
 	return &cfg, nil
 }

pkg/custom-provider/provider.go

@@ -52,14 +52,15 @@ type Runnable interface {
 }
 
 type prometheusProvider struct {
-	mapper     apimeta.RESTMapper
-	kubeClient dynamic.Interface
-	promClient prom.Client
+	mapper         apimeta.RESTMapper
+	kubeClient     dynamic.Interface
+	promClient     prom.Client
+	serviceMetrics *metrics.ServiceMetrics
 
 	SeriesRegistry
 }
 
-func NewPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []naming.MetricNamer, updateInterval time.Duration, maxAge time.Duration) (provider.CustomMetricsProvider, Runnable) {
+func NewPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interface, promClient prom.Client, namers []naming.MetricNamer, updateInterval time.Duration, maxAge time.Duration, serviceMetrics *metrics.ServiceMetrics) (provider.CustomMetricsProvider, Runnable) {
 	lister := &cachingMetricsLister{
 		updateInterval: updateInterval,
 		maxAge:         maxAge,
@@ -67,15 +68,19 @@ func NewPrometheusProvider(mapper apimeta.RESTMapper, kubeClient dynamic.Interfa
 		namers:         namers,
 
 		SeriesRegistry: &basicSeriesRegistry{
-			name:   "custom",
-			mapper: mapper,
+			name:           "custom",
+			mapper:         mapper,
+			serviceMetrics: serviceMetrics,
 		},
+
+		serviceMetrics: serviceMetrics,
 	}
 
 	return &prometheusProvider{
-		mapper:     mapper,
-		kubeClient: kubeClient,
-		promClient: promClient,
+		mapper:         mapper,
+		kubeClient:     kubeClient,
+		promClient:     promClient,
+		serviceMetrics: serviceMetrics,
 
 		SeriesRegistry: lister,
 	}, lister
@@ -101,7 +106,9 @@ func (p *prometheusProvider) metricFor(value pmodel.SampleValue, name types.Name
 func (p *prometheusProvider) metricsFor(valueSet pmodel.Vector, info provider.CustomMetricInfo, namespace string, names []string) (*custom_metrics.MetricValueList, error) {
 	values, found := p.MatchValuesToNames(info, valueSet)
 	if !found {
-		metrics.Errors.WithLabelValues("not_found").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("not_found").Inc()
+		}
 		return nil, provider.NewMetricNotFoundError(info.GroupResource, info.Metric)
 	}
 	res := []custom_metrics.MetricValue{}
@@ -126,7 +133,9 @@ func (p *prometheusProvider) metricsFor(valueSet pmodel.Vector, info provider.Cu
 func (p *prometheusProvider) buildQuery(info provider.CustomMetricInfo, namespace string, names ...string) (pmodel.Vector, error) {
 	query, found := p.QueryForMetric(info, namespace, names...)
 	if !found {
-		metrics.Errors.WithLabelValues("not_found").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("not_found").Inc()
+		}
 		return nil, provider.NewMetricNotFoundError(info.GroupResource, info.Metric)
 	}
 
@@ -134,14 +143,18 @@ func (p *prometheusProvider) buildQuery(info provider.CustomMetricInfo, namespac
 	queryResults, err := p.promClient.Query(context.TODO(), pmodel.Now(), query)
 	if err != nil {
 		klog.Errorf("unable to fetch metrics from prometheus: %v", err)
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("internal").Inc()
+		}
 		// don't leak implementation details to the user
-		metrics.Errors.WithLabelValues("internal").Inc()
 		return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
 	}
 
 	if queryResults.Type != pmodel.ValVector {
 		klog.Errorf("unexpected results from prometheus: expected %s, got %s on results %v", pmodel.ValVector, queryResults.Type, queryResults)
-		metrics.Errors.WithLabelValues("internal").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("internal").Inc()
+		}
 		return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
 	}
 
@@ -157,13 +170,17 @@ func (p *prometheusProvider) GetMetricByName(name types.NamespacedName, info pro
 
 	// associate the metrics
 	if len(queryResults) < 1 {
-		metrics.Errors.WithLabelValues("not_found").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("not_found").Inc()
+		}
 		return nil, provider.NewMetricNotFoundForError(info.GroupResource, info.Metric, name.Name)
 	}
 
 	namedValues, found := p.MatchValuesToNames(info, queryResults)
 	if !found {
-		metrics.Errors.WithLabelValues("not_found").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("not_found").Inc()
+		}
 		return nil, provider.NewMetricNotFoundError(info.GroupResource, info.Metric)
 	}
 
@@ -174,7 +191,9 @@ func (p *prometheusProvider) GetMetricByName(name types.NamespacedName, info pro
 	resultValue, nameFound := namedValues[name.Name]
 	if !nameFound {
 		klog.Errorf("None of the results returned by when fetching metric %s for %q matched the resource name", info.String(), name)
-		metrics.Errors.WithLabelValues("not_found").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("not_found").Inc()
+		}
 		return nil, provider.NewMetricNotFoundForError(info.GroupResource, info.Metric, name.Name)
 	}
 
@@ -187,8 +206,10 @@ func (p *prometheusProvider) GetMetricBySelector(namespace string, selector labe
 	resourceNames, err := helpers.ListObjectNames(p.mapper, p.kubeClient, namespace, selector, info)
 	if err != nil {
 		klog.Errorf("unable to list matching resource names: %v", err)
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("internal").Inc()
+		}
 		// don't leak implementation details to the user
-		metrics.Errors.WithLabelValues("internal").Inc()
 		return nil, apierr.NewInternalError(fmt.Errorf("unable to list matching resources"))
 	}
 
@@ -209,6 +230,7 @@ type cachingMetricsLister struct {
 	updateInterval time.Duration
 	maxAge         time.Duration
 	namers         []naming.MetricNamer
+	serviceMetrics *metrics.ServiceMetrics
 }
 
 func (l *cachingMetricsLister) Run() {
@@ -264,7 +286,9 @@ func (l *cachingMetricsLister) updateMetrics() error {
 	// iterate through, blocking until we've got all results
 	for range l.namers {
 		if err := <-errs; err != nil {
-			metrics.PrometheusUp.Set(0)
+			if l.serviceMetrics != nil {
+				l.serviceMetrics.PrometheusUp.Set(0)
+			}
 			return fmt.Errorf("unable to update list of all metrics: %v", err)
 		}
 		if ss := <-selectorSeriesChan; ss.series != nil {
@@ -272,7 +296,9 @@ func (l *cachingMetricsLister) updateMetrics() error {
 		}
 	}
 	close(errs)
-	metrics.PrometheusUp.Set(1)
+	if l.serviceMetrics != nil {
+		l.serviceMetrics.PrometheusUp.Set(1)
+	}
 
 	newSeries := make([][]prom.Series, len(l.namers))
 	for i, namer := range l.namers {

pkg/custom-provider/series_registry.go

@@ -79,6 +79,8 @@ type basicSeriesRegistry struct {
 	metrics []provider.CustomMetricInfo
 
 	mapper apimeta.RESTMapper
+
+	serviceMetrics *metrics.ServiceMetrics
 }
 
 func (r *basicSeriesRegistry) SetSeries(newSeriesSlices [][]prom.Series, namers []naming.MetricNamer) error {
@@ -127,7 +129,9 @@ func (r *basicSeriesRegistry) SetSeries(newSeriesSlices [][]prom.Series, namers
 	r.mu.Lock()
 	defer r.mu.Unlock()
 
-	metrics.RegistryMetrics.WithLabelValues(r.name).Set(float64(len(newMetrics)))
+	if r.serviceMetrics != nil {
+		r.serviceMetrics.RegistryMetrics.WithLabelValues(r.name).Set(float64(len(newMetrics)))
+	}
 	r.info = newInfo
 	r.metrics = newMetrics
 

pkg/external-provider/external_series_registry.go

@@ -46,6 +46,8 @@ type externalSeriesRegistry struct {
 	metrics []provider.ExternalMetricInfo
 	// metricsInfo is a lookup from a metric to SeriesConverter for the sake of generating queries
 	metricsInfo map[string]seriesInfo
+
+	serviceMetrics *metrics.ServiceMetrics
 }
 
 type seriesInfo struct {
@@ -57,10 +59,11 @@ type seriesInfo struct {
 }
 
 // NewExternalSeriesRegistry creates an ExternalSeriesRegistry driven by the data from the provided MetricLister.
-func NewExternalSeriesRegistry(lister MetricListerWithNotification) ExternalSeriesRegistry {
+func NewExternalSeriesRegistry(lister MetricListerWithNotification, serviceMetrics *metrics.ServiceMetrics) ExternalSeriesRegistry {
 	var registry = externalSeriesRegistry{
-		metrics:     make([]provider.ExternalMetricInfo, 0),
-		metricsInfo: map[string]seriesInfo{},
+		metrics:        make([]provider.ExternalMetricInfo, 0),
+		metricsInfo:    map[string]seriesInfo{},
+		serviceMetrics: serviceMetrics,
 	}
 
 	lister.AddNotificationReceiver(registry.filterAndStoreMetrics)
@@ -105,7 +108,9 @@ func (r *externalSeriesRegistry) filterAndStoreMetrics(result MetricUpdateResult
 	r.mu.Lock()
 	defer r.mu.Unlock()
 
-	metrics.RegistryMetrics.WithLabelValues(r.name).Set(float64(len(apiMetricsCache)))
+	if r.serviceMetrics != nil {
+		r.serviceMetrics.RegistryMetrics.WithLabelValues(r.name).Set(float64(len(apiMetricsCache)))
+	}
 	r.metrics = apiMetricsCache
 	r.metricsInfo = rawMetricsCache
 

pkg/external-provider/provider.go

@@ -40,6 +40,8 @@ type externalPrometheusProvider struct {
 	metricConverter MetricConverter
 
 	seriesRegistry ExternalSeriesRegistry
+
+	serviceMetrics *metrics.ServiceMetrics
 }
 
 func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricSelector labels.Selector, info provider.ExternalMetricInfo) (*external_metrics.ExternalMetricValueList, error) {
@@ -47,12 +49,16 @@ func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricS
 
 	if err != nil {
 		klog.Errorf("unable to generate a query for the metric: %v", err)
-		metrics.Errors.WithLabelValues("internal").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("internal").Inc()
+		}
 		return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
 	}
 
 	if !found {
-		metrics.Errors.WithLabelValues("not_found").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("not_found").Inc()
+		}
 		return nil, provider.NewMetricNotFoundError(p.selectGroupResource(namespace), info.Metric)
 	}
 	// Here is where we're making the query, need to be before here xD
@@ -61,7 +67,9 @@ func (p *externalPrometheusProvider) GetExternalMetric(namespace string, metricS
 	if err != nil {
 		klog.Errorf("unable to fetch metrics from prometheus: %v", err)
 		// don't leak implementation details to the user
-		metrics.Errors.WithLabelValues("internal").Inc()
+		if p.serviceMetrics != nil {
+			p.serviceMetrics.Errors.WithLabelValues("internal").Inc()
+		}
 		return nil, apierr.NewInternalError(fmt.Errorf("unable to fetch metrics"))
 	}
 	return p.metricConverter.Convert(info, queryResults)
@@ -83,14 +91,15 @@ func (p *externalPrometheusProvider) selectGroupResource(namespace string) schem
 }
 
 // NewExternalPrometheusProvider creates an ExternalMetricsProvider capable of responding to Kubernetes requests for external metric data
-func NewExternalPrometheusProvider(promClient prom.Client, namers []naming.MetricNamer, updateInterval time.Duration) (provider.ExternalMetricsProvider, Runnable) {
+func NewExternalPrometheusProvider(promClient prom.Client, namers []naming.MetricNamer, updateInterval time.Duration, serviceMetrics *metrics.ServiceMetrics) (provider.ExternalMetricsProvider, Runnable) {
 	metricConverter := NewMetricConverter()
 	basicLister := NewBasicMetricLister(promClient, namers, updateInterval)
 	periodicLister, _ := NewPeriodicMetricLister(basicLister, updateInterval)
-	seriesRegistry := NewExternalSeriesRegistry(periodicLister)
+	seriesRegistry := NewExternalSeriesRegistry(periodicLister, serviceMetrics)
 	return &externalPrometheusProvider{
 		promClient:      promClient,
 		seriesRegistry:  seriesRegistry,
 		metricConverter: metricConverter,
+		serviceMetrics:  serviceMetrics,
 	}, periodicLister
 }

pkg/metrics/metrics.go

@@ -1,38 +1,72 @@
 package metrics
 
-import "github.com/prometheus/client_golang/prometheus"
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"k8s.io/klog"
+)
 
 const MetricsNamespace = "adapter"
 
-var PrometheusUp = prometheus.NewGauge(prometheus.GaugeOpts{
-	Namespace: MetricsNamespace,
-	Name:      "prometheus_up",
-	Help:      "1 when adapter is able to reach prometheus, 0 otherwise",
-})
-
-var RegistryMetrics = prometheus.NewGaugeVec(prometheus.GaugeOpts{
-	Namespace: MetricsNamespace,
-	Name:      "registry_metrics",
-	Help:      "number of metrics entries in cache registry",
-}, []string{"registry"})
-
-var Errors = prometheus.NewCounterVec(prometheus.CounterOpts{
-	Namespace: MetricsNamespace,
-	Name:      "errors_total",
-	Help:      "number of errors served",
-}, []string{"type"})
-
-var Rules = prometheus.NewGaugeVec(prometheus.GaugeOpts{
-	Namespace: MetricsNamespace,
-	Name:      "roles",
-	Help:      "number of configured rules",
-}, []string{"type"})
-
-func init() {
-	prometheus.MustRegister(
-		PrometheusUp,
-		RegistryMetrics,
-		Errors,
-		Rules,
-	)
+type ServiceMetrics struct {
+	PrometheusUp    prometheus.Gauge
+	RegistryMetrics *prometheus.GaugeVec
+	Errors          *prometheus.CounterVec
+	Rules           *prometheus.GaugeVec
+	Registry        *prometheus.Registry
+}
+
+func NewMetrics() (*ServiceMetrics, error) {
+	ret := &ServiceMetrics{
+		PrometheusUp: prometheus.NewGauge(prometheus.GaugeOpts{
+			Namespace: MetricsNamespace,
+			Name:      "prometheus_up",
+			Help:      "1 when adapter is able to reach prometheus, 0 otherwise",
+		}),
+
+		RegistryMetrics: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: MetricsNamespace,
+			Name:      "registry_metrics",
+			Help:      "number of metrics entries in cache registry",
+		}, []string{"registry"}),
+
+		Errors: prometheus.NewCounterVec(prometheus.CounterOpts{
+			Namespace: MetricsNamespace,
+			Name:      "errors_total",
+			Help:      "number of errors served",
+		}, []string{"type"}),
+
+		Rules: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Namespace: MetricsNamespace,
+			Name:      "roles",
+			Help:      "number of configured rules",
+		}, []string{"type"}),
+
+		Registry: prometheus.NewRegistry(),
+	}
+
+	for collectorName, collector := range map[string]prometheus.Collector{
+		"Go collector":     prometheus.NewGoCollector(),
+		"Prometheus Up":    ret.PrometheusUp,
+		"Registry Metrics": ret.RegistryMetrics,
+		"Errors":           ret.Errors,
+		"Rules":            ret.Rules,
+	} {
+		if err := ret.Registry.Register(collector); err != nil {
+			return nil, fmt.Errorf("during registration of %q: %v", collectorName, err)
+		}
+	}
+
+	return ret, nil
+}
+
+func (m *ServiceMetrics) Run(port uint16) {
+	go func() {
+		mux := http.NewServeMux()
+		mux.Handle("/metrics", promhttp.Handler())
+		klog.Fatal(http.ListenAndServe(fmt.Sprintf(":%d", port), mux))
+	}()
 }