Added WithError(err).

entry.go

@@ -8,6 +8,9 @@ import (
 	"time"
 )
 
+// Defines the key when adding error using WithError.
+var ErrorKey = "error"
+
 // An entry is the final or intermediate Logrus logging entry. It contains all
 // the fields passed with WithField{,s}. It's finally logged when Debug, Info,
 // Warn, Error, Fatal or Panic is called on it. These objects can be reused and
@@ -53,6 +56,11 @@ func (entry *Entry) String() (string, error) {
 	return reader.String(), err
 }
 
+// Add an error as single field (with key "error") to the Entry.
+func (entry *Entry) WithError(err error) *Entry {
+	return entry.WithField(ErrorKey, err)
+}
+
 // Add a single field to the Entry.
 func (entry *Entry) WithField(key string, value interface{}) *Entry {
 	return entry.WithFields(Fields{key: value})

entry_test.go

@@ -8,6 +8,21 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+func TestEntryWithError(t *testing.T) {
+
+	err := fmt.Errorf("kaboom at layer %d", 4711)
+
+	logger := New()
+	logger.Out = &bytes.Buffer{}
+	entry := NewEntry(logger)
+
+	assert.Equal(t, err, entry.WithError(err).Data["error"])
+
+	ErrorKey = "err"
+	assert.Equal(t, err, entry.WithError(err).Data["err"])
+
+}
+
 func TestEntryPanicln(t *testing.T) {
 	errBoom := fmt.Errorf("boom time")