implement expose service, add tests, fix #140

Implements a kompose specific docker compose label "kompose.service.expose" which can be used to expose the specified services externally. The accepted values are of type string.
If the value is set to "true", the provider sets the endpoint automatically, and for any other value, the value is set as the hostname. If multiple ports are defined in a service, the first one is chosen to be the exposed.

Unit tests, functional tests, glide updates and docs have also been added in this commit for the related feature.

vendor/github.com/Sirupsen/logrus/entry.go

@@ -3,21 +3,11 @@ package logrus
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"os"
-	"sync"
 	"time"
 )
 
-var bufferPool *sync.Pool
-
-func init() {
-	bufferPool = &sync.Pool{
-		New: func() interface{} {
-			return new(bytes.Buffer)
-		},
-	}
-}
-
 // Defines the key when adding errors using WithError.
 var ErrorKey = "error"
 
@@ -39,9 +29,6 @@ type Entry struct {
 
 	// Message passed to Debug, Info, Warn, Error, Fatal or Panic
 	Message string
-
-	// When formatter is called in entry.log(), an Buffer may be set to entry
-	Buffer *bytes.Buffer
 }
 
 func NewEntry(logger *Logger) *Entry {
@@ -52,15 +39,21 @@ func NewEntry(logger *Logger) *Entry {
 	}
 }
 
+// Returns a reader for the entry, which is a proxy to the formatter.
+func (entry *Entry) Reader() (*bytes.Buffer, error) {
+	serialized, err := entry.Logger.Formatter.Format(entry)
+	return bytes.NewBuffer(serialized), err
+}
+
 // Returns the string representation from the reader and ultimately the
 // formatter.
 func (entry *Entry) String() (string, error) {
-	serialized, err := entry.Logger.Formatter.Format(entry)
+	reader, err := entry.Reader()
 	if err != nil {
 		return "", err
 	}
-	str := string(serialized)
-	return str, nil
+
+	return reader.String(), err
 }
 
 // Add an error as single field (using the key defined in ErrorKey) to the Entry.
@@ -88,7 +81,6 @@ func (entry *Entry) WithFields(fields Fields) *Entry {
 // This function is not declared with a pointer value because otherwise
 // race conditions will occur when using multiple goroutines
 func (entry Entry) log(level Level, msg string) {
-	var buffer *bytes.Buffer
 	entry.Time = time.Now()
 	entry.Level = level
 	entry.Message = msg
@@ -98,23 +90,20 @@ func (entry Entry) log(level Level, msg string) {
 		fmt.Fprintf(os.Stderr, "Failed to fire hook: %v\n", err)
 		entry.Logger.mu.Unlock()
 	}
-	buffer = bufferPool.Get().(*bytes.Buffer)
-	buffer.Reset()
-	defer bufferPool.Put(buffer)
-	entry.Buffer = buffer
-	serialized, err := entry.Logger.Formatter.Format(&entry)
-	entry.Buffer = nil
+
+	reader, err := entry.Reader()
 	if err != nil {
 		entry.Logger.mu.Lock()
 		fmt.Fprintf(os.Stderr, "Failed to obtain reader, %v\n", err)
 		entry.Logger.mu.Unlock()
-	} else {
-		entry.Logger.mu.Lock()
-		_, err = entry.Logger.Out.Write(serialized)
-		if err != nil {
-			fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
-		}
-		entry.Logger.mu.Unlock()
+	}
+
+	entry.Logger.mu.Lock()
+	defer entry.Logger.mu.Unlock()
+
+	_, err = io.Copy(entry.Logger.Out, reader)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
 	}
 
 	// To avoid Entry#log() returning a value that only would make sense for
@@ -161,7 +150,7 @@ func (entry *Entry) Fatal(args ...interface{}) {
 	if entry.Logger.Level >= FatalLevel {
 		entry.log(FatalLevel, fmt.Sprint(args...))
 	}
-	Exit(1)
+	os.Exit(1)
 }
 
 func (entry *Entry) Panic(args ...interface{}) {
@@ -209,7 +198,7 @@ func (entry *Entry) Fatalf(format string, args ...interface{}) {
 	if entry.Logger.Level >= FatalLevel {
 		entry.Fatal(fmt.Sprintf(format, args...))
 	}
-	Exit(1)
+	os.Exit(1)
 }
 
 func (entry *Entry) Panicf(format string, args ...interface{}) {
@@ -256,7 +245,7 @@ func (entry *Entry) Fatalln(args ...interface{}) {
 	if entry.Logger.Level >= FatalLevel {
 		entry.Fatal(entry.sprintlnn(args...))
 	}
-	Exit(1)
+	os.Exit(1)
 }
 
 func (entry *Entry) Panicln(args ...interface{}) {