@@ -7,15 +7,22 @@ import (

 	"os/signal"

 	"syscall"

-	psignal "github.com/docker/docker/pkg/signal"

+	stackdump "github.com/docker/docker/pkg/signal"

+

+	"github.com/Sirupsen/logrus"

 )

-func setupDumpStackTrap(_ string) {

+func setupDumpStackTrap(root string) {

 	c := make(chan os.Signal, 1)

 	signal.Notify(c, syscall.SIGUSR1)

 	go func() {

 		for range c {

-			psignal.DumpStacks("")

+			path, err := stackdump.DumpStacks(root)

+			if err != nil {

+				logrus.WithError(err).Error("failed to write goroutines dump")

+				continue

+			}

+			logrus.Infof("goroutine stacks written to %s", path)

 		}

 	}()

 }

@@ -35,7 +35,12 @@ func setupDumpStackTrap(root string) {

 		logrus.Debugf("Stackdump - waiting signal at %s", ev)

 		for {

 			syscall.WaitForSingleObject(h, syscall.INFINITE)

-			signal.DumpStacks(root)

+			path, err := signal.DumpStacks(root)

+			if err != nil {

+				logrus.WithError(err).Error("failed to write goroutines dump")

+				continue

+			}

+			logrus.Infof("goroutine stacks written to %s", path)

 		}

 	}()

 }

@@ -1,6 +1,7 @@

 package signal

 import (

+	"fmt"

 	"os"

 	gosignal "os/signal"

 	"path/filepath"

@@ -10,6 +11,7 @@ import (

 	"time"

 	"github.com/Sirupsen/logrus"

+	"github.com/pkg/errors"

 )

 // Trap sets up a simplified signal "trap", appropriate for common

@@ -64,8 +66,11 @@ func Trap(cleanup func()) {

 	}()

 }

-// DumpStacks dumps the runtime stack.

-func DumpStacks(root string) {

+const stacksLogNameTemplate = "goroutine-stacks-%s.log"

+

+// DumpStacks appends the runtime stack into file in dir and returns full path

+// to that file.

+func DumpStacks(dir string) (string, error) {

 	var (

 		buf       []byte

 		stackSize int

@@ -77,32 +82,15 @@ func DumpStacks(root string) {

 		bufferLen *= 2

 	}

 	buf = buf[:stackSize]

-	// Note that if the daemon is started with a less-verbose log-level than "info" (the default), the goroutine

-	// traces won't show up in the log.

-	if root == "" {

-		logrus.Infof("=== BEGIN goroutine stack dump ===\n%s\n=== END goroutine stack dump ===", buf)

-	} else {

-		// Dumps the stacks to a file in the root directory of the daemon

-		// On Windows, this overcomes two issues - one being that if the stack is too big, it doesn't

-		// get written to the event log when the Windows daemon is running as a service.

-		// Second, using logrus, the tabs and new-lines end up getting written as literal

-		// \t and \n's, meaning you need to use something like notepad++ to convert the

-		// output into something readable using 'type' from a command line or notepad/notepad++ etc.

-		path := filepath.Join(root, "goroutine-stacks.log")

-		f, err := os.OpenFile(path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0666)

-		if err != nil {

-			logrus.Warnf("Could not open %s to write the goroutine stacks: %v", path, err)

-			return

-		}

-		defer f.Close()

-		f.WriteString("=== BEGIN goroutine stack dump ===\n")

-		f.WriteString(time.Now().String() + "\n")

-		if _, err := f.Write(buf); err != nil {

-			logrus.Warnf("Could not write goroutine stacks to %s: %v", path, err)

-			return

-		}

-		f.WriteString("=== END goroutine stack dump ===\n")

-		f.Sync()

-		logrus.Infof("goroutine stacks written to %s", path)

+	path := filepath.Join(dir, fmt.Sprintf(stacksLogNameTemplate, time.Now().Format(time.RFC3339)))

+	f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0666)

+	if err != nil {

+		return "", errors.Wrap(err, "failed to open file to write the goroutine stacks")

+	}

+	defer f.Close()

+	if _, err := f.Write(buf); err != nil {

+		return "", errors.Wrap(err, "failed to write goroutine stacks")

 	}

+	f.Sync()

+	return path, nil

 }