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gops/agent/agent.go
Tobias Klauser 55729d43c2 agent: use filepath.Join to construct portfile path
If gopsdir contains a trailing slash, the resulting portfile path will
contain a trailing double slash which might lead to problems in some
circumstances. Moreover iut could also be problematic on platforms where
other path separators are used (e.g. Windows).

Fix this by using filepath.Join to construct the path.
2021-03-09 12:42:07 +01:00

286 lines
7.7 KiB
Go

// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package agent provides hooks programs can register to retrieve
// diagnostics data by using gops.
package agent
import (
"bufio"
"context"
"encoding/binary"
"fmt"
"io"
"io/ioutil"
"net"
"os"
gosignal "os/signal"
"path/filepath"
"runtime"
"runtime/debug"
"runtime/pprof"
"runtime/trace"
"strconv"
"strings"
"sync"
"syscall"
"time"
"github.com/google/gops/internal"
"github.com/google/gops/signal"
)
const defaultAddr = "127.0.0.1:0"
var (
mu sync.Mutex
portfile string
listener net.Listener
units = []string{" bytes", "KB", "MB", "GB", "TB", "PB"}
)
// Options allows configuring the started agent.
type Options struct {
// Addr is the host:port the agent will be listening at.
// Optional.
Addr string
// ConfigDir is the directory to store the configuration file,
// PID of the gops process, filename, port as well as content.
// Optional.
ConfigDir string
// ShutdownCleanup automatically cleans up resources if the
// running process receives an interrupt. Otherwise, users
// can call Close before shutting down.
// Optional.
ShutdownCleanup bool
// ReuseSocketAddrAndPort determines whether the SO_REUSEADDR and
// SO_REUSEADDR socket options should be set on the listening socket of
// the agent. This option is only effective on unix-like OSes and if
// Addr is set to a fixed host:port.
// Optional.
ReuseSocketAddrAndPort bool
}
// Listen starts the gops agent on a host process. Once agent started, users
// can use the advanced gops features. The agent will listen to Interrupt
// signals and exit the process, if you need to perform further work on the
// Interrupt signal use the options parameter to configure the agent
// accordingly.
//
// Note: The agent exposes an endpoint via a TCP connection that can be used by
// any program on the system. Review your security requirements before starting
// the agent.
func Listen(opts Options) error {
mu.Lock()
defer mu.Unlock()
if portfile != "" {
return fmt.Errorf("gops: agent already listening at: %v", listener.Addr())
}
// new
gopsdir := opts.ConfigDir
if gopsdir == "" {
cfgDir, err := internal.ConfigDir()
if err != nil {
return err
}
gopsdir = cfgDir
}
err := os.MkdirAll(gopsdir, os.ModePerm)
if err != nil {
return err
}
if opts.ShutdownCleanup {
gracefulShutdown()
}
addr := opts.Addr
if addr == "" {
addr = defaultAddr
}
var lc net.ListenConfig
if opts.ReuseSocketAddrAndPort {
lc.Control = setsockoptReuseAddrAndPort
}
listener, err = lc.Listen(context.Background(), "tcp", addr)
if err != nil {
return err
}
port := listener.Addr().(*net.TCPAddr).Port
portfile = filepath.Join(gopsdir, strconv.Itoa(os.Getpid()))
err = ioutil.WriteFile(portfile, []byte(strconv.Itoa(port)), os.ModePerm)
if err != nil {
return err
}
go listen()
return nil
}
func listen() {
buf := make([]byte, 1)
for {
fd, err := listener.Accept()
if err != nil {
// No great way to check for this, see https://golang.org/issues/4373.
if !strings.Contains(err.Error(), "use of closed network connection") {
fmt.Fprintf(os.Stderr, "gops: %v\n", err)
}
if netErr, ok := err.(net.Error); ok && !netErr.Temporary() {
break
}
continue
}
if _, err := fd.Read(buf); err != nil {
fmt.Fprintf(os.Stderr, "gops: %v\n", err)
continue
}
if err := handle(fd, buf); err != nil {
fmt.Fprintf(os.Stderr, "gops: %v\n", err)
continue
}
fd.Close()
}
}
func gracefulShutdown() {
c := make(chan os.Signal, 1)
gosignal.Notify(c, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
go func() {
// cleanup the socket on shutdown.
sig := <-c
Close()
ret := 1
if sig == syscall.SIGTERM {
ret = 0
}
os.Exit(ret)
}()
}
// Close closes the agent, removing temporary files and closing the TCP listener.
// If no agent is listening, Close does nothing.
func Close() {
mu.Lock()
defer mu.Unlock()
if portfile != "" {
os.Remove(portfile)
portfile = ""
}
if listener != nil {
listener.Close()
}
}
func formatBytes(val uint64) string {
var i int
var target uint64
for i = range units {
target = 1 << uint(10*(i+1))
if val < target {
break
}
}
if i > 0 {
return fmt.Sprintf("%0.2f%s (%d bytes)", float64(val)/(float64(target)/1024), units[i], val)
}
return fmt.Sprintf("%d bytes", val)
}
func handle(conn io.ReadWriter, msg []byte) error {
switch msg[0] {
case signal.StackTrace:
return pprof.Lookup("goroutine").WriteTo(conn, 2)
case signal.GC:
runtime.GC()
_, err := conn.Write([]byte("ok"))
return err
case signal.MemStats:
var s runtime.MemStats
runtime.ReadMemStats(&s)
fmt.Fprintf(conn, "alloc: %v\n", formatBytes(s.Alloc))
fmt.Fprintf(conn, "total-alloc: %v\n", formatBytes(s.TotalAlloc))
fmt.Fprintf(conn, "sys: %v\n", formatBytes(s.Sys))
fmt.Fprintf(conn, "lookups: %v\n", s.Lookups)
fmt.Fprintf(conn, "mallocs: %v\n", s.Mallocs)
fmt.Fprintf(conn, "frees: %v\n", s.Frees)
fmt.Fprintf(conn, "heap-alloc: %v\n", formatBytes(s.HeapAlloc))
fmt.Fprintf(conn, "heap-sys: %v\n", formatBytes(s.HeapSys))
fmt.Fprintf(conn, "heap-idle: %v\n", formatBytes(s.HeapIdle))
fmt.Fprintf(conn, "heap-in-use: %v\n", formatBytes(s.HeapInuse))
fmt.Fprintf(conn, "heap-released: %v\n", formatBytes(s.HeapReleased))
fmt.Fprintf(conn, "heap-objects: %v\n", s.HeapObjects)
fmt.Fprintf(conn, "stack-in-use: %v\n", formatBytes(s.StackInuse))
fmt.Fprintf(conn, "stack-sys: %v\n", formatBytes(s.StackSys))
fmt.Fprintf(conn, "stack-mspan-inuse: %v\n", formatBytes(s.MSpanInuse))
fmt.Fprintf(conn, "stack-mspan-sys: %v\n", formatBytes(s.MSpanSys))
fmt.Fprintf(conn, "stack-mcache-inuse: %v\n", formatBytes(s.MCacheInuse))
fmt.Fprintf(conn, "stack-mcache-sys: %v\n", formatBytes(s.MCacheSys))
fmt.Fprintf(conn, "other-sys: %v\n", formatBytes(s.OtherSys))
fmt.Fprintf(conn, "gc-sys: %v\n", formatBytes(s.GCSys))
fmt.Fprintf(conn, "next-gc: when heap-alloc >= %v\n", formatBytes(s.NextGC))
lastGC := "-"
if s.LastGC != 0 {
lastGC = fmt.Sprint(time.Unix(0, int64(s.LastGC)))
}
fmt.Fprintf(conn, "last-gc: %v\n", lastGC)
fmt.Fprintf(conn, "gc-pause-total: %v\n", time.Duration(s.PauseTotalNs))
fmt.Fprintf(conn, "gc-pause: %v\n", s.PauseNs[(s.NumGC+255)%256])
fmt.Fprintf(conn, "gc-pause-end: %v\n", s.PauseEnd[(s.NumGC+255)%256])
fmt.Fprintf(conn, "num-gc: %v\n", s.NumGC)
fmt.Fprintf(conn, "num-forced-gc: %v\n", s.NumForcedGC)
fmt.Fprintf(conn, "gc-cpu-fraction: %v\n", s.GCCPUFraction)
fmt.Fprintf(conn, "enable-gc: %v\n", s.EnableGC)
fmt.Fprintf(conn, "debug-gc: %v\n", s.DebugGC)
case signal.Version:
fmt.Fprintf(conn, "%v\n", runtime.Version())
case signal.HeapProfile:
return pprof.WriteHeapProfile(conn)
case signal.CPUProfile:
if err := pprof.StartCPUProfile(conn); err != nil {
return err
}
time.Sleep(30 * time.Second)
pprof.StopCPUProfile()
case signal.Stats:
fmt.Fprintf(conn, "goroutines: %v\n", runtime.NumGoroutine())
fmt.Fprintf(conn, "OS threads: %v\n", pprof.Lookup("threadcreate").Count())
fmt.Fprintf(conn, "GOMAXPROCS: %v\n", runtime.GOMAXPROCS(0))
fmt.Fprintf(conn, "num CPU: %v\n", runtime.NumCPU())
case signal.BinaryDump:
path, err := os.Executable()
if err != nil {
return err
}
f, err := os.Open(path)
if err != nil {
return err
}
defer f.Close()
_, err = bufio.NewReader(f).WriteTo(conn)
return err
case signal.Trace:
if err := trace.Start(conn); err != nil {
return err
}
time.Sleep(5 * time.Second)
trace.Stop()
case signal.SetGCPercent:
perc, err := binary.ReadVarint(bufio.NewReader(conn))
if err != nil {
return err
}
fmt.Fprintf(conn, "New GC percent set to %v. Previous value was %v.\n", perc, debug.SetGCPercent(int(perc)))
}
return nil
}