fix for body field writer exhaustion

core/logger/attrs.go

@@ -96,6 +96,11 @@ func Body(val any) zap.Field {
 		if err != nil {
 			return zap.String(BodyAttr, fmt.Sprintf("%#v", val))
 		}
+		if seeker, ok := item.(io.Seeker); ok {
+			_, _ = seeker.Seek(0, 0)
+		} else if writer, ok := item.(io.Writer); ok {
+			_, _ = writer.Write(data)
+		}
 		var m interface{}
 		if err := json.Unmarshal(data, &m); err == nil {
 			return zap.Any(BodyAttr, m)

core/logger/attrs_test.go

@@ -4,6 +4,8 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
+	"github.com/stretchr/testify/require"
+	"go.uber.org/zap"
 	"io"
 	"net/http"
 	"testing"
@@ -62,94 +64,133 @@ func TestHTTPStatusName(t *testing.T) {
 
 func TestStreamID(t *testing.T) {
 	var cases = []struct {
+		name   string
 		input  interface{}
 		result interface{}
 	}{
 		{
+			name:   "empty",
 			input:  "",
 			result: "",
 		},
 		{
+			name:   "string",
 			input:  "test body",
 			result: "test body",
 		},
 	}
 	for _, c := range cases {
-		val := StreamID(c.input)
+		t.Run(c.name, func(t *testing.T) {
-		assert.Equal(t, StreamIDAttr, val.Key)
+			val := StreamID(c.input)
-		assert.Equal(t, c.result, val.String)
+			assert.Equal(t, StreamIDAttr, val.Key)
+			assert.Equal(t, c.result, val.String)
+		})
 	}
 }
 
 func TestBody(t *testing.T) {
 	var cases = []struct {
-		input  interface{}
+		name    string
-		result interface{}
+		input   interface{}
+		result  interface{}
+		asserts func(t *testing.T, field zap.Field, input, result interface{})
 	}{
 		{
+			name:   "empty string input",
 			input:  "",
 			result: nil,
 		},
 		{
+			name:   "nil input",
 			input:  nil,
 			result: nil,
 		},
 		{
+			name:   "string input",
 			input:  "test body",
 			result: "test body",
 		},
 		{
+			name:   "json input",
 			input:  `{"success":true}`,
 			result: map[string]interface{}{"success": true},
 		},
 		{
+			name:   "empty byte slice input",
 			input:  []byte{},
 			result: nil,
 		},
 		{
-			input:  nil,
+			name:   "byte slice input",
-			result: nil,
-		},
-		{
 			input:  []byte("test body"),
 			result: "test body",
 		},
 		{
+			name:   "json byte slice input",
 			input:  []byte(`{"success":true}`),
 			result: map[string]interface{}{"success": true},
 		},
 		{
+			name: "eof reader input",
 			input: newReaderMock(func(p []byte) (n int, err error) {
 				return 0, io.EOF
 			}),
 			result: nil,
 		},
 		{
+			name:   "empty reader input",
 			input:  newReaderMockData([]byte{}),
 			result: nil,
 		},
 		{
+			name:   "data reader input",
 			input:  newReaderMockData([]byte("ooga booga")),
 			result: "ooga booga",
 		},
-
 		{
+			name:   "json data reader input",
 			input:  newReaderMockData([]byte(`{"success":true}`)),
 			result: map[string]interface{}{"success": true},
 		},
+		{
+			name:   "check that seeker is rewound",
+			input:  bytes.NewReader([]byte(`{"success":true}`)),
+			result: map[string]interface{}{"success": true},
+			asserts: func(t *testing.T, val zap.Field, input, result interface{}) {
+				data, err := io.ReadAll(input.(io.Reader))
+				require.NoError(t, err)
+				assert.Equal(t, []byte(`{"success":true}`), data)
+			},
+		},
+		{
+			name:   "check that writer is rebuilt",
+			input:  bytes.NewBuffer([]byte(`{"success":true}`)),
+			result: map[string]interface{}{"success": true},
+			asserts: func(t *testing.T, val zap.Field, input, result interface{}) {
+				data, err := io.ReadAll(input.(io.Reader))
+				require.NoError(t, err)
+				assert.Equal(t, []byte(`{"success":true}`), data)
+			},
+		},
 	}
 	for _, c := range cases {
-		val := Body(c.input)
+		t.Run(c.name, func(t *testing.T) {
-		assert.Equal(t, BodyAttr, val.Key)
+			val := Body(c.input)
+			assert.Equal(t, BodyAttr, val.Key)
 
-		switch assertion := c.result.(type) {
+			switch assertion := c.result.(type) {
-		case string:
+			case string:
-			assert.Equal(t, assertion, val.String)
+				assert.Equal(t, assertion, val.String)
-		case int:
+			case int:
-			assert.Equal(t, assertion, int(val.Integer))
+				assert.Equal(t, assertion, int(val.Integer))
-		default:
+			default:
-			assert.Equal(t, c.result, val.Interface)
+				assert.Equal(t, c.result, val.Interface)
-		}
+			}
+
+			if c.asserts != nil {
+				c.asserts(t, val, c.input, c.result)
+			}
+		})
 	}
 }