core: metrics v2 (#1370)

* outposts: add ldap metrics, move ping to 9100

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* outpost: add flow_executor metrics

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* use port 9300 for metrics, add core metrics port

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

* outposts/controllers/k8s: add service monitor creation support

Signed-off-by: Jens Langhammer <jens.langhammer@beryju.org>

internal/web/metrics.go

@@ -0,0 +1,58 @@
+package web
+
+import (
+	"io/ioutil"
+	"net/http"
+
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	log "github.com/sirupsen/logrus"
+	"goauthentik.io/internal/config"
+)
+
+var (
+	Requests = promauto.NewHistogramVec(prometheus.HistogramOpts{
+		Name: "authentik_main_requests",
+		Help: "The total number of configured providers",
+	}, []string{"dest"})
+)
+
+func RunMetricsServer() {
+	m := mux.NewRouter()
+	m.Path("/metrics").HandlerFunc(func(rw http.ResponseWriter, r *http.Request) {
+		defer promhttp.InstrumentMetricHandler(
+			prometheus.DefaultRegisterer, promhttp.HandlerFor(prometheus.DefaultGatherer, promhttp.HandlerOpts{
+				DisableCompression: true,
+			}),
+		).ServeHTTP(rw, r)
+
+		// Get upstream metrics
+		re, err := http.NewRequest("GET", "http://localhost:8000/metrics/", nil)
+		if err != nil {
+			log.WithError(err).Warning("failed to get upstream metrics")
+			return
+		}
+		re.SetBasicAuth("monitor", config.G.SecretKey)
+		res, err := http.DefaultClient.Do(re)
+		if err != nil {
+			log.WithError(err).Warning("failed to get upstream metrics")
+			return
+		}
+		bm, err := ioutil.ReadAll(res.Body)
+		if err != nil {
+			log.WithError(err).Warning("failed to get upstream metrics")
+			return
+		}
+		_, err = rw.Write(bm)
+		if err != nil {
+			log.WithError(err).Warning("failed to get upstream metrics")
+			return
+		}
+	})
+	err := http.ListenAndServe(config.G.Web.ListenMetrics, m)
+	if err != nil {
+		panic(err)
+	}
+}