diff --git a/core/logx/writer.go b/core/logx/writer.go
index e494df609e79..70182a70a9fc 100644
--- a/core/logx/writer.go
+++ b/core/logx/writer.go
@@ -241,7 +241,6 @@ func output(writer io.Writer, level string, val interface{}, fields ...LogField)
 
 	switch atomic.LoadUint32(&encoding) {
 	case plainEncodingType:
-		level = wrapLevelWithColor(level)
 		writePlainAny(writer, level, val, buildFields(fields...)...)
 	default:
 		entry := make(logEntryWithFields)
@@ -290,6 +289,8 @@ func writeJson(writer io.Writer, info interface{}) {
 }
 
 func writePlainAny(writer io.Writer, level string, val interface{}, fields ...string) {
+	level = wrapLevelWithColor(level)
+
 	switch v := val.(type) {
 	case string:
 		writePlainText(writer, level, v, fields...)
diff --git a/core/logx/writer_test.go b/core/logx/writer_test.go
index 6d96808cfe08..edc4ff9804e5 100644
--- a/core/logx/writer_test.go
+++ b/core/logx/writer_test.go
@@ -124,18 +124,27 @@ func TestWritePlainAny(t *testing.T) {
 	assert.Contains(t, buf.String(), "foo")
 
 	buf.Reset()
-	writePlainAny(nil, levelInfo, make(chan int))
+	writePlainAny(nil, levelError, make(chan int))
 	assert.Contains(t, buf.String(), "unsupported type")
-	writePlainAny(nil, levelInfo, 100)
+	writePlainAny(nil, levelSlow, 100)
 	assert.Contains(t, buf.String(), "100")
 
 	buf.Reset()
-	writePlainAny(hardToWriteWriter{}, levelInfo, 100)
+	writePlainAny(hardToWriteWriter{}, levelStat, 100)
 	assert.Contains(t, buf.String(), "write error")
 
 	buf.Reset()
-	writePlainAny(hardToWriteWriter{}, levelInfo, "foo")
+	writePlainAny(hardToWriteWriter{}, levelSevere, "foo")
 	assert.Contains(t, buf.String(), "write error")
+
+	buf.Reset()
+	writePlainAny(hardToWriteWriter{}, levelAlert, "foo")
+	assert.Contains(t, buf.String(), "write error")
+
+	buf.Reset()
+	writePlainAny(hardToWriteWriter{}, levelFatal, "foo")
+	assert.Contains(t, buf.String(), "write error")
+
 }
 
 type mockedEntry struct {
diff --git a/rest/handler/loghandler_test.go b/rest/handler/loghandler_test.go
index aa96d5a42781..25019dbf2f9a 100644
--- a/rest/handler/loghandler_test.go
+++ b/rest/handler/loghandler_test.go
@@ -1,6 +1,8 @@
 package handler
 
 import (
+	"bytes"
+	"io"
 	"io/ioutil"
 	"log"
 	"net/http"
@@ -44,6 +46,33 @@ func TestLogHandler(t *testing.T) {
 	}
 }
 
+func TestLogHandlerVeryLong(t *testing.T) {
+	var buf bytes.Buffer
+	for i := 0; i < limitBodyBytes<<1; i++ {
+		buf.WriteByte('a')
+	}
+
+	req := httptest.NewRequest(http.MethodPost, "http://localhost", &buf)
+	handler := LogHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		r.Context().Value(internal.LogContext).(*internal.LogCollector).Append("anything")
+		io.Copy(ioutil.Discard, r.Body)
+		w.Header().Set("X-Test", "test")
+		w.WriteHeader(http.StatusServiceUnavailable)
+		_, err := w.Write([]byte("content"))
+		assert.Nil(t, err)
+
+		flusher, ok := w.(http.Flusher)
+		assert.True(t, ok)
+		flusher.Flush()
+	}))
+
+	resp := httptest.NewRecorder()
+	handler.ServeHTTP(resp, req)
+	assert.Equal(t, http.StatusServiceUnavailable, resp.Code)
+	assert.Equal(t, "test", resp.Header().Get("X-Test"))
+	assert.Equal(t, "content", resp.Body.String())
+}
+
 func TestLogHandlerSlow(t *testing.T) {
 	handlers := []func(handler http.Handler) http.Handler{
 		LogHandler,
@@ -106,6 +135,28 @@ func TestSetSlowThreshold(t *testing.T) {
 	assert.Equal(t, time.Second, slowThreshold.Load())
 }
 
+func TestWrapMethodWithColor(t *testing.T) {
+	// no tty
+	assert.Equal(t, http.MethodGet, wrapMethod(http.MethodGet))
+	assert.Equal(t, http.MethodPost, wrapMethod(http.MethodPost))
+	assert.Equal(t, http.MethodPut, wrapMethod(http.MethodPut))
+	assert.Equal(t, http.MethodDelete, wrapMethod(http.MethodDelete))
+	assert.Equal(t, http.MethodPatch, wrapMethod(http.MethodPatch))
+	assert.Equal(t, http.MethodHead, wrapMethod(http.MethodHead))
+	assert.Equal(t, http.MethodOptions, wrapMethod(http.MethodOptions))
+	assert.Equal(t, http.MethodConnect, wrapMethod(http.MethodConnect))
+	assert.Equal(t, http.MethodTrace, wrapMethod(http.MethodTrace))
+}
+
+func TestWrapStatusCodeWithColor(t *testing.T) {
+	// no tty
+	assert.Equal(t, "200", wrapStatusCode(http.StatusOK))
+	assert.Equal(t, "302", wrapStatusCode(http.StatusFound))
+	assert.Equal(t, "404", wrapStatusCode(http.StatusNotFound))
+	assert.Equal(t, "500", wrapStatusCode(http.StatusInternalServerError))
+	assert.Equal(t, "503", wrapStatusCode(http.StatusServiceUnavailable))
+}
+
 func BenchmarkLogHandler(b *testing.B) {
 	b.ReportAllocs()