From 55d28fb124dc4caa9047c5ca9150c82f073e70b2 Mon Sep 17 00:00:00 2001 From: Nicolas Lacasse Date: Wed, 3 Oct 2018 10:32:35 -0700 Subject: [PATCH] runsc: Dup debug log file to stderr, so sentry panics don't get lost. Docker and containerd do not expose runsc's stderr, so tracking down sentry panics can be painful. If we have a debug log file, we should send panics (and all stderr data) to the log file. PiperOrigin-RevId: 215585559 Change-Id: I3844259ed0cd26e26422bcdb40dded302740b8b6 --- runsc/main.go | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/runsc/main.go b/runsc/main.go index 2a18c4b9e..7e704a127 100644 --- a/runsc/main.go +++ b/runsc/main.go @@ -177,6 +177,10 @@ func main() { if *debugLogFD > -1 { f := os.NewFile(uintptr(*debugLogFD), "debug log file") + // Dup f to stderr so we capture stack traces on panic. + if err := syscall.Dup2(int(f.Fd()), int(os.Stderr.Fd())); err != nil { + cmd.Fatalf("error dup'ing fd %d to stderr: %v", f.Fd(), err) + } e = log.MultiEmitter{e, log.GoogleEmitter{&log.Writer{Next: f}}} } else if *debugLogDir != "" { if err := os.MkdirAll(*debugLogDir, 0775); err != nil { @@ -187,6 +191,10 @@ func main() { if err != nil { cmd.Fatalf("error opening debug log file in %q: %v", *debugLogDir, err) } + // Dup f to stderr so we capture stack traces on panic. + if err := syscall.Dup2(int(f.Fd()), int(os.Stderr.Fd())); err != nil { + cmd.Fatalf("error dup'ing fd %d to stderr: %v", f.Fd(), err) + } e = log.MultiEmitter{e, log.GoogleEmitter{&log.Writer{Next: f}}} }