Add --profile-{cpu,mem} flags

The flags allow debugging `crictl` with respect to CPU and memory
consumption.

Signed-off-by: Sascha Grunert <sgrunert@redhat.com>

Author: saschagrunert

.golangci.yml

@@ -122,6 +122,8 @@ linters-settings:
         disabled: true
   nestif:
     min-complexity: 17
+  maintidx:
+    under: 10
   godox:
     keywords:
       - BUG
@@ -132,7 +134,7 @@ linters-settings:
   cyclop:
     max-complexity: 37
   gocognit:
-    min-complexity: 53
+    min-complexity: 63
   gci:
     sections:
       - standard

cmd/crictl/main.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"os"
 	"runtime"
+	"runtime/pprof"
 	"slices"
 	"sort"
 	"strings"
@@ -270,12 +271,34 @@ func main() {
 			Usage: "Address to which the gRPC tracing collector will send spans to.",
 			Value: "127.0.0.1:4317",
 		},
+		&cli.StringFlag{
+			Name:  "profile-cpu",
+			Usage: "Write a pprof CPU profile to the provided path.",
+		},
+		&cli.StringFlag{
+			Name:  "profile-mem",
+			Usage: "Write a pprof memory profile to the provided path.",
+		},
 	}
 
 	app.Before = func(context *cli.Context) (err error) {
 		var config *common.ServerConfiguration
 		var exePath string
 
+		cpuProfilePath := context.String("profile-cpu")
+		if cpuProfilePath != "" {
+			logrus.Infof("Creating CPU profile in: %s", cpuProfilePath)
+
+			file, err := os.Create(cpuProfilePath)
+			if err != nil {
+				return fmt.Errorf("could not create CPU profile: %w", err)
+			}
+
+			if err := pprof.StartCPUProfile(file); err != nil {
+				return fmt.Errorf("could not start CPU profiling: %w", err)
+			}
+		}
+
 		if exePath, err = os.Executable(); err != nil {
 			logrus.Fatal(err)
 		}
@@ -355,6 +378,29 @@ func main() {
 
 		return nil
 	}
+
+	app.After = func(ctx *cli.Context) error {
+		memProfilePath := ctx.String("profile-mem")
+		if memProfilePath != "" {
+			logrus.Infof("Creating memory profile in: %s", memProfilePath)
+
+			file, err := os.Create(memProfilePath)
+			if err != nil {
+				return fmt.Errorf("could not create memory profile: %w", err)
+			}
+			defer file.Close()
+
+			// Ensure up to date data
+			runtime.GC()
+
+			if err := pprof.WriteHeapProfile(file); err != nil {
+				return fmt.Errorf("could not write memory profile: %w", err)
+			}
+		}
+
+		return nil
+	}
+
 	// sort all flags
 	for _, cmd := range app.Commands {
 		sort.Sort(cli.FlagsByName(cmd.Flags))
@@ -373,4 +419,7 @@ func main() {
 			logrus.Errorf("Unable to shutdown tracer provider: %v", err)
 		}
 	}
+
+	// noop when profiling is not enabled
+	pprof.StopCPUProfile()
 }