运行时/CGO:pthread_create失败:资源暂时不可用

Question

我目前有这个函数，它通过ffmpeg管道传输多个youtubedl命令，然后将ffmpeg的输出通过管道传输到HTTP客户端。

func pipeThruFfmpegToMp4(vi *VideoInfo, rw web.ResponseWriter) error {
var ffmpeg *exec.Cmd
ffmpeg = exec.Command(
"ffmpeg",
"-i", "-",
"-i", "pipe:3",
"-c:v", "copy", "-c:a", "copy",
"-preset", "veryfast",
"-metadata", fmt.Sprintf(`title=%s`, vi.GetTitle()),
"-movflags", "frag_keyframe+empty_moov",
"-f", "mp4",
"-")

youtubevideo := exec.Command(YoutubeDLPath, "-c", "-f", fmt.Sprintf("%s/bestvideo[ext=mp4]/bestvideo/best", vi.GetFormat()), "--no-cache-dir", "--restrict-filenames", "--hls-prefer-native", "-o", "-", fmt.Sprintf("%s", vi.GetVideoUrl()))
fmt.Println(youtubevideo)
youtube := exec.Command(YoutubeDLPath, "-c", "-f", "bestaudio[ext=m4a]/bestaudio/best", "--no-cache-dir", "--restrict-filenames", "--hls-prefer-native", "-o", "-", fmt.Sprintf("%s", vi.GetVideoUrl()))
fmt.Println(youtube)
var ytvbuf, ytbuf, ffbuf bytes.Buffer
youtubevideo.Stderr = &ytvbuf
youtube.Stderr = &ytbuf
ffmpeg.Stderr = &ffbuf
video, err := youtubevideo.StdoutPipe()
if err != nil {
log.Printf("pipeThruFfmpegToMp4: %vn", err)
return err
}
pipe3, err := youtube.StdoutPipe()
if err != nil {
log.Printf("pipeThruFfmpegToMp4: %vn", err)
return err
}
ffmpeg.Stdin = video
ffmpeg.ExtraFiles = []*os.File{pipe3.(*os.File)}
ffmpeg.Stdout = rw
// Headers sent, no turning back now
rw.Header().Set("Content-Type", "video/mp4")
rw.Header().Set("Content-Disposition", fmt.Sprintf("attachment;filename="%s.mp4"", vi.GetSlug()))
rw.Flush()
ffmpeg.Start()
youtubevideo.Start()
youtube.Start()
ffmpeg.Wait()
youtubevideo.Wait()
youtube.Wait()
// check ytvbuf, ytbuf, ffbuf for stderr errors
if ffbuf.Len() != 0 {
rollbar.Error(rollbar.ERR, err, &rollbar.Field{"stderr", ffbuf.String()})
log.Printf("pipeThruFfmpegToMp4: %vn", ffbuf.String())
}
if ytvbuf.Len() != 0 {
rollbar.Error(rollbar.ERR, err, &rollbar.Field{"stderr", ytvbuf.String()})
log.Printf("pipeThruYouTubevDLToMp4: %vn", ytvbuf.String())
}
if ytbuf.Len() != 0 {
rollbar.Error(rollbar.ERR, err, &rollbar.Field{"stderr", ytbuf.String()})
log.Printf("pipeThruYouTubeDLToMp4: %vn", ytbuf.String())
}
return nil
}

问题是一切运行良好，但是过了一段时间，服务器上的 ram 开始填满，直到它出现错误runtime/cgo: pthread_create failed: Resource temporarily unavailable

我不确定这是否是内存泄漏，或者 youtube-dl 的任何一个实例都没有正确关闭，或者 ffmpeg 是否没有正确关闭，只是随着程序运行更多而消耗越来越多的 ram，直到程序崩溃并出现此错误

runtime/cgo: pthread_create failed: Resource temporarily unavailable
SIGABRT: abort
PC=0x7f083501fe97 m=128 sigcode=18446744073709551610
goroutine 0 [idle]:
runtime: unknown pc 0x7f083501fe97
stack: frame={sp:0x7f05ff7fd7d0, fp:0x0} stack=[0x7f05feffe288,0x7f05ff7fde88)
00007f05ff7fd6d0:  00007f05ff7fd700  0000ffff00001fa0
00007f05ff7fd6e0:  00007f05ff7fdbe0  00007f05f8000da0
00007f05ff7fd6f0:  0000000000000000  000000000093032c
00007f05ff7fd700:  0000000000000000  00007f0835600ec3
00007f05ff7fd710:  0000000000000005  0000000000000000
00007f05ff7fd720:  000000c0000ce120  00007f0834ff1ce0
00007f05ff7fd730:  00007f05ff7fdaf0  00007f083560870a
00007f05ff7fd740:  0000000000000000  0000000000000000
00007f05ff7fd750:  0000000000000000  00007f05ff7fdbe0
00007f05ff7fd760:  2525252525252525  2525252525252525
00007f05ff7fd770:  000000ffffffffff  0000000000000000
00007f05ff7fd780:  000000ffffffffff  0000000000000000
00007f05ff7fd790:  000000c00010d1a0  000000c000953740
00007f05ff7fd7a0:  000000c0000ce120  000000c000cf2300
00007f05ff7fd7b0:  000000c00010d260  000000c001f4e180
00007f05ff7fd7c0:  000000c001f4e000  000000c00169f680
00007f05ff7fd7d0: <0000000000000000  000000c001f34180
00007f05ff7fd7e0:  6e75720000000000  6f67632f656d6974
00007f05ff7fd7f0:  0000000000000000  0000000000000000
00007f05ff7fd800:  000000c000cf2300  000000c00010d260
00007f05ff7fd810:  000000c001f4e180  000000c001f4e000
00007f05ff7fd820:  000000c00169f680  000000c00169f500
00007f05ff7fd830:  000000c001f34180  000000c001f34000
00007f05ff7fd840:  000000c000c92780  000000c001ec2600
00007f05ff7fd850:  fffffffe7fffffff  ffffffffffffffff
00007f05ff7fd860:  ffffffffffffffff  ffffffffffffffff
00007f05ff7fd870:  ffffffffffffffff  ffffffffffffffff
00007f05ff7fd880:  ffffffffffffffff  ffffffffffffffff
00007f05ff7fd890:  ffffffffffffffff  ffffffffffffffff
00007f05ff7fd8a0:  ffffffffffffffff  ffffffffffffffff
00007f05ff7fd8b0:  ffffffffffffffff  ffffffffffffffff
00007f05ff7fd8c0:  ffffffffffffffff  ffffffffffffffff
runtime: unknown pc 0x7f083501fe97
stack: frame={sp:0x7f05ff7fd7d0, fp:0x0} stack=[0x7f05feffe288,0x7f05ff7fde88)
00007f05ff7fd6d0:  00007f05ff7fd700  0000ffff00001fa0
00007f05ff7fd6e0:  00007f05ff7fdbe0  00007f05f8000da0
00007f05ff7fd6f0:  0000000000000000  000000000093032c
00007f05ff7fd700:  0000000000000000  00007f0835600ec3
00007f05ff7fd710:  0000000000000005  0000000000000000

我也尝试过用CGO_ENABLED=0构建二进制文件，即使我什至没有import "c"，但这最终也

出错了

runtime: failed to create new OS thread (have 21 already; errno=11)
runtime: may need to increase max user processes (ulimit -u)
fatal error: newosproc

我的极限已经很慷慨了，这也许也是一个问题？还是我可能需要增加管道尺寸？

$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 192907
max locked memory       (kbytes, -l) 16384
max memory size         (kbytes, -m) unlimited
open files                      (-n) 100000
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 65536
cpu time               (seconds, -t) unlimited
max user processes              (-u) 63883
virtual memory          (kbytes, -v) unlimited

无论哪种方式，我都希望得到任何和所有帮助。 这是整个程序的链接，这是golang-nuts论坛中关于此问题的帖子

Answer 1

我有时会遇到问题，您的代码不会杀死youtube-dl进程。视频已转换，但保留了该过程。作为第一个指标，观察进程计数，如下所示：

ps | grep youtube-dl | wc -l

可以让子进程超时，对于一个子进程，这将如下所示：

package main
import (
"bytes"
"fmt"
"os/exec"
"time"
)
func main() {
// Sleep is used, so we can control how long it runs.
cmd := exec.Command("sleep", "2")
// Use a bytes.Buffer to get the output
var buf bytes.Buffer
cmd.Stdout = &buf
cmd.Start()
// Use a channel to signal completion so we can use a select statement
done := make(chan error)
go func() { done <- cmd.Wait() }()
// Start a timer, should be higher for your video conversion, 
// I suggest you use a value that fits both your videos and server capabilities
timeout := time.After(2 * time.Second)
// The select statement allows us to execute based on which channel
// we get a message from first.
select {
case <-timeout:
// Timeout happened first, kill the process and print a message.
cmd.Process.Kill()
fmt.Println("Command timed out")
case err := <-done:
// Command completed before timeout. Print output and error if it exists.
fmt.Println("Output:", buf.String())
if err != nil {
fmt.Println("Non-zero exit code:", err)
}
}
}

在您的情况下，您可以更换

ffmpeg.Start()
youtubevideo.Start()
youtube.Start()
ffmpeg.Wait()
youtubevideo.Wait()
youtube.Wait()

跟

ffmpeg.Start()
youtubevideo.Start()
youtube.Start()
commands := 3
done := make(chan error)
go func() { done <- ffmpeg.Wait() }()
go func() { done <- youtubevideo.Wait() }()
go func() { done <- youtube.Wait() }()
timeout := time.After(1 * time.Hour)
Loop:
for {
select {
case <-timeout:
ffmpeg.Process.Kill()
youtubevideo.Process.Kill()
youtube.Process.Kill()
log.Println("Conversion timed out")
break Loop
case err := <-done:
if err != nil {
log.Println("Non-zero exit code:", err)
}
commands = commands - 1
if commands == 0 {
break Loop
}
}
}

Answer 2

所以经过一些调试，在凯文的回答的帮助下。 似乎youtube-dl在成功后并没有关闭。

鉴于如果ffmpeg完成，那么运行youtube-dl实例没有任何意义，并且由于Wait()函数正在等待youtube-dl完成，但它似乎从未发送它的完成信号，我继续并不得不添加一个 kill 来也杀死子子进程。

所以我不得不添加更改

ffmpeg.Start()
youtubevideo.Start()
youtube.Start()
ffmpeg.Wait()
youtubevideo.Wait()
youtube.Wait()

对此

youtube.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
youtubevideo.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
ffmpeg.Start()
youtubevideo.Start()
youtube.Start()
ffmpeg.Wait()
syscall.Kill(-youtube.Process.Pid, syscall.SIGKILL)
syscall.Kill(-youtubevideo.Process.Pid, syscall.SIGKILL)
youtubevideo.Wait()
youtube.Wait()

请注意，由于它似乎制作了某种子进程，youtube.Process.Kill()实际上并没有杀死该进程，这就是为什么我不得不使用syscall，并且Setpgid: true