Add collectd parser (#2654)

logger/logger.go

@@ -4,11 +4,14 @@ import (
 	"io"
 	"log"
 	"os"
+	"regexp"
 	"time"
 
 	"github.com/influxdata/wlog"
 )
 
+var prefixRegex = regexp.MustCompile("^[DIWE]!")
+
 // newTelegrafWriter returns a logging-wrapped writer.
 func newTelegrafWriter(w io.Writer) io.Writer {
 	return &telegrafLog{
@@ -21,7 +24,13 @@ type telegrafLog struct {
 }
 
 func (t *telegrafLog) Write(b []byte) (n int, err error) {
-	return t.writer.Write(append([]byte(time.Now().UTC().Format(time.RFC3339)+" "), b...))
+	var line []byte
+	if !prefixRegex.Match(b) {
+		line = append([]byte(time.Now().UTC().Format(time.RFC3339)+" I! "), b...)
+	} else {
+		line = append([]byte(time.Now().UTC().Format(time.RFC3339)+" "), b...)
+	}
+	return t.writer.Write(line)
 }
 
 // SetupLogging configures the logging output.

logger/logger_test.go

@@ -51,6 +51,19 @@ func TestErrorWriteLogToFile(t *testing.T) {
 	assert.Equal(t, f[19:], []byte("Z E! TEST\n"))
 }
 
+func TestAddDefaultLogLevel(t *testing.T) {
+	tmpfile, err := ioutil.TempFile("", "")
+	assert.NoError(t, err)
+	defer func() { os.Remove(tmpfile.Name()) }()
+
+	SetupLogging(true, false, tmpfile.Name())
+	log.Printf("TEST")
+
+	f, err := ioutil.ReadFile(tmpfile.Name())
+	assert.NoError(t, err)
+	assert.Equal(t, f[19:], []byte("Z I! TEST\n"))
+}
+
 func BenchmarkTelegrafLogWrite(b *testing.B) {
 	var msg = []byte("test")
 	var buf bytes.Buffer