FIX #2746 Improve shell detection in bugsnag reports

Signed-off-by: David Gageot <david@gageot.net>

libmachine/crashreport/crash_report.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/bugsnag/bugsnag-go"
 	"github.com/docker/machine/libmachine/log"
+	"github.com/docker/machine/libmachine/shell"
 	"github.com/docker/machine/version"
 )
 
@@ -125,12 +126,8 @@ func addFile(path string, metaData *bugsnag.MetaData) {
 }
 
 func detectRunningShell(metaData *bugsnag.MetaData) {
-	shell := os.Getenv("SHELL")
-	if shell != "" {
-		metaData.Add("device", "shell", shell)
-	}
-	shell = os.Getenv("__fish_bin_dir")
-	if shell != "" {
+	shell, err := shell.Detect()
+	if err == nil {
 		metaData.Add("device", "shell", shell)
 	}
 }

libmachine/shell/shell.go

@@ -0,0 +1,30 @@
+// +build !windows
+
+package shell
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+var (
+	ErrUnknownShell = errors.New("Error: Unknown shell")
+)
+
+// Detect detects user's current shell.
+func Detect() (string, error) {
+	shell := os.Getenv("SHELL")
+
+	if shell == "" {
+		fmt.Printf("The default lines below are for a sh/bash shell, you can specify the shell you're using, with the --shell flag.\n\n")
+		return "", ErrUnknownShell
+	}
+
+	if os.Getenv("__fish_bin_dir") != "" {
+		return "fish", nil
+	}
+
+	return filepath.Base(shell), nil
+}

libmachine/shell/shell_test.go

@@ -0,0 +1,31 @@
+package shell
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDetectBash(t *testing.T) {
+	defer func(shell string) { os.Setenv("SHELL", shell) }(os.Getenv("SHELL"))
+	os.Setenv("SHELL", "/bin/bash")
+
+	shell, err := Detect()
+
+	assert.Equal(t, "bash", shell)
+	assert.NoError(t, err)
+}
+
+func TestDetectFish(t *testing.T) {
+	defer func(shell string) { os.Setenv("SHELL", shell) }(os.Getenv("SHELL"))
+	os.Setenv("SHELL", "/bin/bash")
+
+	defer func(fishDir string) { os.Setenv("__fish_bin_dir", fishDir) }(os.Getenv("__fish_bin_dir"))
+	os.Setenv("__fish_bin_dir", "/usr/local/Cellar/fish/2.2.0/bin")
+
+	shell, err := Detect()
+
+	assert.Equal(t, "fish", shell)
+	assert.NoError(t, err)
+}

libmachine/shell/shell_unix_test.go

@@ -0,0 +1,20 @@
+// +build !windows
+
+package shell
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUnknownShell(t *testing.T) {
+	defer func(shell string) { os.Setenv("SHELL", shell) }(os.Getenv("SHELL"))
+	os.Setenv("SHELL", "")
+
+	shell, err := Detect()
+
+	assert.Equal(t, err, ErrUnknownShell)
+	assert.Empty(t, shell)
+}

libmachine/shell/shell_windows.go

@@ -0,0 +1,76 @@
+package shell
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"syscall"
+	"unsafe"
+)
+
+// re-implementation of private function in https://github.com/golang/go/blob/master/src/syscall/syscall_windows.go#L945
+func getProcessEntry(pid int) (pe *syscall.ProcessEntry32, err error) {
+	snapshot, err := syscall.CreateToolhelp32Snapshot(syscall.TH32CS_SNAPPROCESS, 0)
+	if err != nil {
+		return nil, err
+	}
+	defer syscall.CloseHandle(syscall.Handle(snapshot))
+
+	var processEntry syscall.ProcessEntry32
+	processEntry.Size = uint32(unsafe.Sizeof(processEntry))
+	err = syscall.Process32First(snapshot, &processEntry)
+	if err != nil {
+		return nil, err
+	}
+
+	for {
+		if processEntry.ProcessID == uint32(pid) {
+			pe = &processEntry
+			return
+		}
+
+		err = syscall.Process32Next(snapshot, &processEntry)
+		if err != nil {
+			return nil, err
+		}
+	}
+}
+
+// startedBy returns the exe file name of the parent process.
+func startedBy() (exefile string, err error) {
+	ppid := os.Getppid()
+
+	pe, err := getProcessEntry(ppid)
+	if err != nil {
+		return "", err
+	}
+
+	name := syscall.UTF16ToString(pe.ExeFile[:])
+	return name, nil
+}
+
+func Detect() (string, error) {
+	shell := os.Getenv("SHELL")
+
+	if shell == "" {
+		shell, err := startedBy()
+		if err != nil {
+			return "cmd", err // defaulting to cmd
+		}
+		if strings.Contains(strings.ToLower(shell), "powershell") {
+			return "powershell", nil
+		} else if strings.Contains(strings.ToLower(shell), "cmd") {
+			return "cmd", nil
+		} else {
+			fmt.Printf("You can further specify your shell with either 'cmd' or 'powershell' with the --shell flag.\n\n")
+			return "cmd", nil // this could be either powershell or cmd, defaulting to cmd
+		}
+	}
+
+	if os.Getenv("__fish_bin_dir") != "" {
+		return "fish", nil
+	}
+
+	return filepath.Base(shell), nil
+}

libmachine/shell/shell_windows_test.go

@@ -0,0 +1,25 @@
+package shell
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDetect(t *testing.T) {
+	defer func(shell string) { os.Setenv("SHELL", shell) }(os.Getenv("SHELL"))
+	os.Setenv("SHELL", "")
+
+	shell, err := Detect()
+
+	assert.Equal(t, "cmd", shell)
+	assert.NoError(t, err)
+}
+
+func TestStartedBy(t *testing.T) {
+	shell, err := startedBy()
+
+	assert.Equal(t, "go.exe", shell)
+	assert.NoError(t, err)
+}