dumpstack.go

/*
Copyright 2023 The OpenYurt Authors.

Licensed under the Apache License, Version 2.0 (the License);
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an AS IS BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package util

import (
	"fmt"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"syscall"

	"k8s.io/klog/v2"
)

func SetupDumpStackTrap(logDir string, stopCh <-chan struct{}) {
	c := make(chan os.Signal, 1)
	signal.Notify(c, syscall.SIGUSR1)

	go func() {
		for {
			select {
			case <-c:
				dumpStacks(true, logDir)
			case <-stopCh:
				return
			}
		}
	}()
}

func dumpStacks(writeToFile bool, logDir string) {
	var (
		buf       []byte
		stackSize int
	)
	bufferLen := 16384
	for stackSize == len(buf) {
		buf = make([]byte, bufferLen)
		stackSize = runtime.Stack(buf, true)
		bufferLen *= 2
	}
	buf = buf[:stackSize]
	klog.Infof("=== BEGIN goroutine stack dump ===\n%s\n=== END goroutine stack dump ===", buf)

	if writeToFile {
		// Also write to file to aid gathering diagnostics
		name := filepath.Join(logDir, fmt.Sprintf("yurthub.%d.stacks.log", os.Getpid()))
		f, err := os.Create(name)
		if err != nil {
			return
		}
		defer f.Close()
		f.WriteString(string(buf))
		klog.Infof("goroutine stack dump written to %s", name)
	}
}