pkg/metrics: move profiles into the metrics server

This change:
- renames pkg/prometheus into pkg/metrics
- renames the prometheus_addr config to metrics_addr
- adds pprof endpoints to the metrics server
- removes profile/trace cli flags
- adds endpoints for profiling to the metrics server

pkg/metrics/server.go

@@ -1,10 +1,11 @@
-// Package prometheus implements a standalone HTTP server for serving a
-// Prometheus metrics endpoint.
-package prometheus
+// Package metrics implements a standalone HTTP server for serving pprof
+// profiles and Prometheus metrics.
+package metrics
 
 import (
 	"context"
 	"net/http"
+	"net/http/pprof"
 
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 
@@ -31,10 +32,19 @@ func (s *Server) Stop() stop.Result {
 // NewServer creates a new instance of a Prometheus server that asynchronously
 // serves requests.
 func NewServer(addr string) *Server {
+	mux := http.NewServeMux()
+
+	mux.Handle("/metrics", promhttp.Handler())
+	mux.HandleFunc("/debug/pprof/", pprof.Index)
+	mux.HandleFunc("/debug/pprof/cmdline", pprof.Cmdline)
+	mux.HandleFunc("/debug/pprof/profile", pprof.Profile)
+	mux.HandleFunc("/debug/pprof/symbol", pprof.Symbol)
+	mux.HandleFunc("/debug/pprof/trace", pprof.Trace)
+
 	s := &Server{
 		srv: &http.Server{
 			Addr:    addr,
-			Handler: promhttp.Handler(),
+			Handler: mux,
 		},
 	}