formatter for logstash (http://logstash.net)

README.md

@@ -321,6 +321,7 @@ The built-in logging formatters are:
     field to `true`.  To force no colored output even if there is a TTY  set the
     `DisableColors` field to `true`
 * `logrus.JSONFormatter`. Logs fields as JSON.
+* `logrus.LogstashFormatter`. Logs fields as Logstash Events (http://logstash.net).
 
 Third party logging formatters:
 

logstash_formatter.go

@@ -0,0 +1,47 @@
+package logrus
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+// Formatter generates json in logstash format.
+// Logstash site: http://logstash.net/
+type LogstashFormatter struct {
+	Type string // if not empty use for logstash type field.
+}
+
+func (f *LogstashFormatter) Format(entry *Entry) ([]byte, error) {
+	entry.Data["@version"] = 1
+	entry.Data["@timestamp"] = entry.Time.Format(time.RFC3339)
+
+	// set message field
+	v, ok := entry.Data["message"]
+	if ok {
+		entry.Data["fields.message"] = v
+	}
+	entry.Data["message"] = entry.Message
+
+	// set level field
+	v, ok = entry.Data["level"]
+	if ok {
+		entry.Data["fields.level"] = v
+	}
+	entry.Data["level"] = entry.Level.String()
+
+	// set type field
+	if f.Type != "" {
+		v, ok = entry.Data["type"]
+		if ok {
+			entry.Data["fields.type"] = v
+		}
+		entry.Data["type"] = f.Type
+	}
+
+	serialized, err := json.Marshal(entry.Data)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to marshal fields to JSON, %v", err)
+	}
+	return append(serialized, '\n'), nil
+}