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gops/main.go
2016-11-13 20:38:17 -08:00

127 lines
2.5 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.
// Program gops is a tool to list currently running Go processes.
package main
import (
"flag"
"fmt"
"log"
"os"
"github.com/google/gops/internal/objfile"
ps "github.com/keybase/go-ps"
)
const helpText = `Usage: gops is a tool to list and diagnose Go processes.
gops Lists all Go processes currently running.
gops [cmd] -p=<pid> See the section below.
Commands:
stack Prints the stack trace.
gc Runs the garbage collector and blocks until successful.
memstats Prints the garbage collection stats.
version Prints the Go version used to build the program.
All commands require the agent running on the Go process.
`
// TODO(jbd): add link that explains the use of agent.
var (
heap = flag.Bool("heap", false, "enables heap profile")
cpu = flag.Bool("cpu", false, "enables CPU profile")
)
func main() {
if len(os.Args) < 2 {
processes()
return
}
cmd := os.Args[1]
if cmd == "help" {
usage("")
}
fn, ok := cmds[cmd]
if !ok {
usage("unknown subcommand")
}
var pid int
flag.IntVar(&pid, "p", -1, "")
flag.CommandLine.Parse(os.Args[2:])
if pid == -1 {
usage("missing -p=<pid> flag")
}
if err := fn(pid); err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
os.Exit(1)
}
}
func processes() {
pss, err := ps.Processes()
if err != nil {
log.Fatal(err)
}
var undetermined int
for _, pr := range pss {
if pr.Pid() == 0 {
// ignore system process
continue
}
name, err := pr.Path()
if err != nil {
undetermined++
continue
}
ok, err := isGo(name)
if err != nil {
// TODO(jbd): worth to report the number?
continue
}
if ok {
// TODO(jbd): List if the program is running the agent.
fmt.Printf("%d\t%v\t(%v)\n", pr.Pid(), pr.Executable(), name)
}
}
if undetermined > 0 {
fmt.Printf("\n%d processes left undetermined\n", undetermined)
}
}
func isGo(executable string) (ok bool, err error) {
obj, err := objfile.Open(executable)
if err != nil {
return false, err
}
defer obj.Close()
symbols, err := obj.Symbols()
if err != nil {
return false, err
}
// TODO(jbd): find a faster way to determine Go programs.
for _, s := range symbols {
if s.Name == "runtime.buildVersion" {
return true, nil
}
}
return false, nil
}
func usage(msg string) {
if msg != "" {
fmt.Printf("gops: %v\n", msg)
}
fmt.Fprintf(os.Stderr, "%v\n", helpText)
os.Exit(1)
}