Add pprof profiling endpoints to the agent

This adds a pprof server running on 6060 to aid in investigating memory
usage of the agents. This can be eneabled or disable through a flag
`profiling`

Signed-off-by: oluwole.fadeyi <oluwole.fadeyi@jetstack.io>

Author: oluwole.fadeyi

cmd/agent.go

@@ -117,4 +117,11 @@ func init() {
 		os.Getenv("API_TOKEN"),
 		"Token used for authentication when API tokens are in use on the backend",
 	)
+	agentCmd.PersistentFlags().BoolVarP(
+		&agent.Profiling,
+		"enable-pprof",
+		"",
+		false,
+		"Enables the pprof profiling server on the agent (port: 6060).",
+	)
 }

pkg/agent/run.go

@@ -4,9 +4,12 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"log"
+	"net/http"
+	_ "net/http/pprof"
 	"net/url"
 	"os"
 	"strings"
@@ -50,6 +53,9 @@ var StrictMode bool
 // APIToken is an authentication token used for the backend API as an alternative to oauth flows.
 var APIToken string
 
+// Profiling flag enabled pprof endpoints to run on the agent
+var Profiling bool
+
 // schema version of the data sent by the agent.
 // The new default version is v2.
 // In v2 the agent posts data readings using api.gathereredResources
@@ -64,6 +70,16 @@ func Run(cmd *cobra.Command, args []string) {
 	defer cancel()
 	config, preflightClient := getConfiguration()
 
+	if Profiling {
+		log.Printf("pprof profiling was enabled.\nRunning profiling on port :6060")
+		go func() {
+			err := http.ListenAndServe(":6060", nil)
+			if err != nil && errors.Is(err, http.ErrServerClosed) {
+				log.Fatalf("failed to run pprof profiler: %s", err)
+			}
+		}()
+	}
+
 	dataGatherers := map[string]datagatherer.DataGatherer{}
 	var wg sync.WaitGroup