Cleanup stdout/stderr log initialization

Signed-off-by: Jean-Laurent de Morlhon <jeanlaurent@morlhon.net>

commands/config.go

@@ -2,7 +2,6 @@ package commands
 
 import (
 	"fmt"
-	"os"
 
 	"github.com/docker/machine/libmachine"
 	"github.com/docker/machine/libmachine/check"
@@ -12,7 +11,7 @@ import (
 func cmdConfig(c CommandLine, api libmachine.API) error {
 	// Ensure that log messages always go to stderr when this command is
 	// being run (it is intended to be run in a subshell)
-	log.SetOutWriter(os.Stderr)
+	log.RedirectStdOutToStdErr()
 
 	if len(c.Args()) != 1 {
 		return ErrExpectedOneMachine

commands/env.go

@@ -50,7 +50,7 @@ func cmdEnv(c CommandLine, api libmachine.API) error {
 
 	// Ensure that log messages always go to stderr when this command is
 	// being run (it is intended to be run in a subshell)
-	log.SetOutWriter(os.Stderr)
+	log.RedirectStdOutToStdErr()
 
 	if c.Bool("unset") {
 		shellCfg, err = shellCfgUnset(c, api)

libmachine/drivers/plugin/localbinary/plugin_test.go

@@ -82,13 +82,13 @@ func TestExecServer(t *testing.T) {
 
 	logReader, logWriter := io.Pipe()
 
-	log.SetOutWriter(logWriter)
-	log.SetErrWriter(logWriter)
+	log.GetStandardLogger().OutWriter = logWriter
+	log.GetStandardLogger().ErrWriter = logWriter
 
 	defer func() {
 		log.IsDebug = false
-		log.SetOutWriter(os.Stdout)
-		log.SetErrWriter(os.Stderr)
+		log.GetStandardLogger().OutWriter = os.Stdout
+		log.GetStandardLogger().ErrWriter = os.Stderr
 	}()
 
 	stdoutReader, stdoutWriter := io.Pipe()

libmachine/examples/vbox_create.go

@@ -4,17 +4,17 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"os"
 
 	"github.com/docker/machine/drivers/virtualbox"
 	"github.com/docker/machine/libmachine"
 	"github.com/docker/machine/libmachine/log"
+	"os"
 )
 
 func main() {
 	log.IsDebug = true
-	log.SetOutWriter(os.Stdout)
-	log.SetErrWriter(os.Stderr)
+	log.GetStandardLogger().OutWriter = os.Stdout
+	log.GetStandardLogger().ErrWriter = os.Stderr
 
 	client := libmachine.NewClient("/tmp/automatic")
 

libmachine/log/log.go

@@ -1,33 +1,24 @@
 package log
 
 import (
-	"io"
 	"os"
 	"sync"
 )
 
 var (
 	l = StandardLogger{
-		mu: &sync.Mutex{},
+		OutWriter: os.Stdout,
+		ErrWriter: os.Stderr,
+		mu:        &sync.Mutex{},
 	}
 	IsDebug = false
 )
 
 type Fields map[string]interface{}
 
-func init() {
-	// TODO: Is this really the best approach?  I worry that it will create
-	// implicit behavior which may be problmatic for users of the lib.
-	SetOutWriter(os.Stdout)
-	SetErrWriter(os.Stderr)
-}
-
-func SetOutWriter(w io.Writer) {
-	l.OutWriter = w
-}
-
-func SetErrWriter(w io.Writer) {
-	l.ErrWriter = w
+// RedirectStdOutToStdErr prevents any log from corrupting the output
+func RedirectStdOutToStdErr() {
+	l.OutWriter = l.ErrWriter
 }
 
 func Debug(args ...interface{}) {
@@ -54,7 +45,6 @@ func Infof(fmtString string, args ...interface{}) {
 	l.Infof(fmtString, args...)
 }
 
-
 func Fatal(args ...interface{}) {
 	l.Fatal(args...)
 }
@@ -79,4 +69,6 @@ func WithField(fieldName string, field interface{}) Logger {
 
 func WithFields(fields Fields) Logger {
 	return l.WithFields(fields)
+func GetStandardLogger() *StandardLogger {
+	return &l
 }