diff --git a/vendor/github.com/sirupsen/logrus/json_formatter.go b/vendor/github.com/sirupsen/logrus/json_formatter.go
new file mode 100644
index 0000000..2605753
--- /dev/null
+++ b/vendor/github.com/sirupsen/logrus/json_formatter.go
@@ -0,0 +1,105 @@
+package logrus
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+)
+
+type fieldKey string
+
+// FieldMap allows customization of the key names for default fields.
+type FieldMap map[fieldKey]string
+
+func (f FieldMap) resolve(key fieldKey) string {
+	if k, ok := f[key]; ok {
+		return k
+	}
+
+	return string(key)
+}
+
+// JSONFormatter formats logs into parsable json
+type JSONFormatter struct {
+	// TimestampFormat sets the format used for marshaling timestamps.
+	TimestampFormat string
+
+	// DisableTimestamp allows disabling automatic timestamps in output
+	DisableTimestamp bool
+
+	// DataKey allows users to put all the log entry parameters into a nested dictionary at a given key.
+	DataKey string
+
+	// FieldMap allows users to customize the names of keys for default fields.
+	// As an example:
+	// formatter := &JSONFormatter{
+	//   	FieldMap: FieldMap{
+	// 		 FieldKeyTime:  "@timestamp",
+	// 		 FieldKeyLevel: "@level",
+	// 		 FieldKeyMsg:   "@message",
+	// 		 FieldKeyFunc:  "@caller",
+	//    },
+	// }
+	FieldMap FieldMap
+
+	// PrettyPrint will indent all json logs
+	PrettyPrint bool
+}
+
+// Format renders a single log entry
+func (f *JSONFormatter) Format(entry *Entry) ([]byte, error) {
+	data := make(Fields, len(entry.Data)+4)
+	for k, v := range entry.Data {
+		switch v := v.(type) {
+		case error:
+			// Otherwise errors are ignored by `encoding/json`
+			// https://github.com/sirupsen/logrus/issues/137
+			data[k] = v.Error()
+		default:
+			data[k] = v
+		}
+	}
+
+	if f.DataKey != "" {
+		newData := make(Fields, 4)
+		newData[f.DataKey] = data
+		data = newData
+	}
+
+	prefixFieldClashes(data, f.FieldMap, entry.HasCaller())
+
+	timestampFormat := f.TimestampFormat
+	if timestampFormat == "" {
+		timestampFormat = defaultTimestampFormat
+	}
+
+	if entry.err != "" {
+		data[f.FieldMap.resolve(FieldKeyLogrusError)] = entry.err
+	}
+	if !f.DisableTimestamp {
+		data[f.FieldMap.resolve(FieldKeyTime)] = entry.Time.Format(timestampFormat)
+	}
+	data[f.FieldMap.resolve(FieldKeyMsg)] = entry.Message
+	data[f.FieldMap.resolve(FieldKeyLevel)] = entry.Level.String()
+	if entry.HasCaller() {
+		data[f.FieldMap.resolve(FieldKeyFunc)] = entry.Caller.Function
+		data[f.FieldMap.resolve(FieldKeyFile)] = fmt.Sprintf("%s:%d", entry.Caller.File, entry.Caller.Line)
+	}
+
+	var b *bytes.Buffer
+	if entry.Buffer != nil {
+		b = entry.Buffer
+	} else {
+		b = &bytes.Buffer{}
+	}
+
+	encoder := json.NewEncoder(b)
+	if f.PrettyPrint {
+		encoder.SetIndent("", "  ")
+	}
+	if err := encoder.Encode(data); err != nil {
+		return nil, fmt.Errorf("Failed to marshal fields to JSON, %v", err)
+	}
+
+	return b.Bytes(), nil
+}