cmd: split newlines in logrus stderr output to new entry

Currently the logrus hook runs formatter once for each entry, which causes newlines to be escaped see sirupsen/logrus#608
Because of this multiline messages end up looking like

```go
logrus.Info(`some message
same mesage multiline 1`)
logrus.Info("next meesage")
```

```
LEVEL some message
same message multiline 1
LEVEL next messsage
```

With this change the hook will format each entry's message split on newlines so that,

```go
logrus.Info(`some message
same mesage multiline 1`)
logrus.Info("next meesage")
```

```
LEVEL some message
LEVEL same message multiline 1
LEVEL next messsage
```

This will help 2 cases,
- openshift@af9b49c like informational messages that are require multiple lines to be more user-friendly.
- meesages from cluster operators on install-complete failure see openshift#4242

cmd/openshift-install/log.go

@@ -4,6 +4,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"strings"
 
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -15,6 +16,8 @@ type fileHook struct {
 	file      io.Writer
 	formatter logrus.Formatter
 	level     logrus.Level
+
+	truncateAtNewLine bool
 }
 
 func newFileHook(file io.Writer, level logrus.Level, formatter logrus.Formatter) *fileHook {
@@ -25,6 +28,12 @@ func newFileHook(file io.Writer, level logrus.Level, formatter logrus.Formatter)
 	}
 }
 
+func newFileHookWithNewlineTruncate(file io.Writer, level logrus.Level, formatter logrus.Formatter) *fileHook {
+	f := newFileHook(file, level, formatter)
+	f.truncateAtNewLine = true
+	return f
+}
+
 func (h fileHook) Levels() []logrus.Level {
 	var levels []logrus.Level
 	for _, level := range logrus.AllLevels {
@@ -37,13 +46,31 @@ func (h fileHook) Levels() []logrus.Level {
 }
 
 func (h *fileHook) Fire(entry *logrus.Entry) error {
-	line, err := h.formatter.Format(entry)
-	if err != nil {
-		return err
+	// logrus reuses the same entry for each invocation of hooks.
+	// so we need to make sure we leave them message field as we received.
+	orig := entry.Message
+	defer func() { entry.Message = orig }()
+
+	msgs := []string{orig}
+	if h.truncateAtNewLine {
+		msgs = strings.Split(orig, "\n")
+	}
+
+	for _, msg := range msgs {
+		// this makes it easier to call format on entry
+		// easy without creating a new one for each split message.
+		entry.Message = msg
+		line, err := h.formatter.Format(entry)
+		if err != nil {
+			return err
+		}
+
+		if _, err := h.file.Write(line); err != nil {
+			return err
+		}
 	}
 
-	_, err = h.file.Write(line)
-	return err
+	return nil
 }
 
 func setupFileHook(baseDir string) func() {

cmd/openshift-install/main.go

@@ -95,7 +95,7 @@ func runRootCmd(cmd *cobra.Command, args []string) {
 		level = logrus.InfoLevel
 	}
 
-	logrus.AddHook(newFileHook(os.Stderr, level, &logrus.TextFormatter{
+	logrus.AddHook(newFileHookWithNewlineTruncate(os.Stderr, level, &logrus.TextFormatter{
 		// Setting ForceColors is necessary because logrus.TextFormatter determines
 		// whether or not to enable colors by looking at the output of the logger.
 		// In this case, the output is ioutil.Discard, which is not a terminal.
@@ -104,6 +104,7 @@ func runRootCmd(cmd *cobra.Command, args []string) {
 		ForceColors:            terminal.IsTerminal(int(os.Stderr.Fd())),
 		DisableTimestamp:       true,
 		DisableLevelTruncation: true,
+		DisableQuote:           true,
 	}))
 
 	if err != nil {