Add IdP metrics (#521)

management/server/telemetry/app_metrics.go

@@ -0,0 +1,160 @@
+package telemetry
+
+import (
+	"context"
+	"fmt"
+	"github.com/gorilla/mux"
+	prometheus2 "github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	log "github.com/sirupsen/logrus"
+	"go.opentelemetry.io/otel/exporters/prometheus"
+	metric2 "go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/sdk/metric"
+	"net"
+	"net/http"
+	"reflect"
+)
+
+const defaultEndpoint = "/metrics"
+
+// MockAppMetrics mocks the AppMetrics interface
+type MockAppMetrics struct {
+	GetMeterFunc       func() metric2.Meter
+	CloseFunc          func() error
+	ExposeFunc         func(port int, endpoint string) error
+	IDPMetricsFunc     func() *IDPMetrics
+	HTTPMiddlewareFunc func() *HTTPMiddleware
+}
+
+// GetMeter mocks the GetMeter function of the AppMetrics interface
+func (mock *MockAppMetrics) GetMeter() metric2.Meter {
+	if mock.GetMeterFunc != nil {
+		return mock.GetMeterFunc()
+	}
+	return nil
+}
+
+// Close mocks the Close function of the AppMetrics interface
+func (mock *MockAppMetrics) Close() error {
+	if mock.CloseFunc != nil {
+		return mock.CloseFunc()
+	}
+	return fmt.Errorf("unimplemented")
+}
+
+// Expose mocks the Expose function of the AppMetrics interface
+func (mock *MockAppMetrics) Expose(port int, endpoint string) error {
+	if mock.ExposeFunc != nil {
+		return mock.ExposeFunc(port, endpoint)
+	}
+	return fmt.Errorf("unimplemented")
+}
+
+// IDPMetrics mocks the IDPMetrics function of the IDPMetrics interface
+func (mock *MockAppMetrics) IDPMetrics() *IDPMetrics {
+	if mock.IDPMetricsFunc != nil {
+		return mock.IDPMetricsFunc()
+	}
+	return nil
+}
+
+// HTTPMiddleware mocks the HTTPMiddleware function of the IDPMetrics interface
+func (mock *MockAppMetrics) HTTPMiddleware() *HTTPMiddleware {
+	if mock.HTTPMiddlewareFunc != nil {
+		return mock.HTTPMiddlewareFunc()
+	}
+	return nil
+}
+
+// AppMetrics is metrics interface
+type AppMetrics interface {
+	GetMeter() metric2.Meter
+	Close() error
+	Expose(port int, endpoint string) error
+	IDPMetrics() *IDPMetrics
+	HTTPMiddleware() *HTTPMiddleware
+}
+
+// defaultAppMetrics are core application metrics based on OpenTelemetry https://opentelemetry.io/
+type defaultAppMetrics struct {
+	// Meter can be used by different application parts to create counters and measure things
+	Meter          metric2.Meter
+	listener       net.Listener
+	ctx            context.Context
+	idpMetrics     *IDPMetrics
+	httpMiddleware *HTTPMiddleware
+}
+
+// IDPMetrics returns metrics for the idp package
+func (appMetrics *defaultAppMetrics) IDPMetrics() *IDPMetrics {
+	return appMetrics.idpMetrics
+}
+
+// HTTPMiddleware returns metrics for the http api package
+func (appMetrics *defaultAppMetrics) HTTPMiddleware() *HTTPMiddleware {
+	return appMetrics.httpMiddleware
+}
+
+// Close stop application metrics HTTP handler and closes listener.
+func (appMetrics *defaultAppMetrics) Close() error {
+	if appMetrics.listener == nil {
+		return nil
+	}
+	return appMetrics.listener.Close()
+}
+
+// Expose metrics on a given port and endpoint. If endpoint is empty a defaultEndpoint one will be used.
+// Exposes metrics in the Prometheus format https://prometheus.io/
+func (appMetrics *defaultAppMetrics) Expose(port int, endpoint string) error {
+	if endpoint == "" {
+		endpoint = defaultEndpoint
+	}
+	rootRouter := mux.NewRouter()
+	rootRouter.Handle(endpoint, promhttp.HandlerFor(
+		prometheus2.DefaultGatherer,
+		promhttp.HandlerOpts{EnableOpenMetrics: true}))
+	listener, err := net.Listen("tcp4", fmt.Sprintf(":%d", port))
+	if err != nil {
+		return err
+	}
+	appMetrics.listener = listener
+	go func() {
+		err := http.Serve(listener, rootRouter)
+		if err != nil {
+			return
+		}
+	}()
+
+	log.Infof("enabled application metrics and exposing on http://%s", listener.Addr().String())
+
+	return nil
+}
+
+// GetMeter returns metrics meter that can be used to add various counters
+func (appMetrics *defaultAppMetrics) GetMeter() metric2.Meter {
+	return appMetrics.Meter
+}
+
+// NewDefaultAppMetrics and expose them via defaultEndpoint on a given HTTP port
+func NewDefaultAppMetrics(ctx context.Context) (AppMetrics, error) {
+	exporter, err := prometheus.New()
+	if err != nil {
+		return nil, err
+	}
+
+	provider := metric.NewMeterProvider(metric.WithReader(exporter))
+	pkg := reflect.TypeOf(defaultEndpoint).PkgPath()
+	meter := provider.Meter(pkg)
+
+	idpMetrics, err := NewIDPMetrics(ctx, meter)
+	if err != nil {
+		return nil, err
+	}
+
+	middleware, err := NewMetricsMiddleware(ctx, meter)
+	if err != nil {
+		return nil, err
+	}
+
+	return &defaultAppMetrics{Meter: meter, ctx: ctx, idpMetrics: idpMetrics, httpMiddleware: middleware}, nil
+}