Merge pull request #15 from infiniteloopcloud/limit-recoverer-result

Add DebugStackLengthLimit to the RecovererLogStack

middlewares/recoverer.go

@@ -265,14 +265,22 @@ func cW(w io.Writer, useColor bool, color []byte, s string, args ...interface{})
 	}
 }
 
-type RecovererLogStack struct{}
+type RecovererLogStack struct {
+	DebugStackLengthLimit int
+}
 
 func (l RecovererLogStack) Parse(ctx context.Context, debugStack []byte, rvr interface{}) ([]byte, error) {
+	debugStackMsgWrapped := strings.Join(strings.Split(string(debugStack), "\n"), "|")
+	if l.DebugStackLengthLimit > 0 {
+		if lenDebugStack := len(debugStackMsgWrapped); lenDebugStack > l.DebugStackLengthLimit {
+			debugStackMsgWrapped = debugStackMsgWrapped[:l.DebugStackLengthLimit]
+		}
+	}
 	parsedLog := log.Parse(ctx, log.ErrorLevelString, "panic happen",
 		fmt.Errorf("panic happen: %v", rvr),
 		log.Field{
 			Key:   "debug_stack",
-			Value: strings.Join(strings.Split(string(debugStack), "\n"), "|"),
+			Value: debugStackMsgWrapped,
 		})
 	return []byte(parsedLog), nil
 }

middlewares/recoverer_test.go

@@ -3,6 +3,8 @@ package middlewares
 import (
 	"bytes"
 	"context"
+	"encoding/json"
+	"errors"
 	"io"
 	"net/http"
 	"net/http/httptest"
@@ -11,6 +13,8 @@ import (
 	"testing"
 
 	"github.com/go-chi/chi/v5"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func panicingHandler(http.ResponseWriter, *http.Request) { panic("foo") }
@@ -98,6 +102,42 @@ func TestRecovererCustomParser(t *testing.T) {
 	t.Fatal("First func call line should be something like 'goroutine 18 [running]:'")
 }
 
+// TestRecovererLogStack_ParseDebugStackLimit is testing if the debug_stack string cut was successful
+// if the limit is less than the length of the debug_stack
+func TestRecovererLogStack_ParseDebugStackLimit(t *testing.T) {
+	ls := RecovererLogStack{DebugStackLengthLimit: 1024}
+	a1000 := strings.Repeat("a", 1000)
+	b1000 := strings.Repeat("b", 1000)
+	parse, err := ls.Parse(context.Background(), []byte(a1000+b1000), errors.New("some panic"))
+	require.NoError(t, err)
+	var labels map[string]interface{}
+	require.NoError(t, json.Unmarshal(parse, &labels))
+	debugStackI, ok := labels["debug_stack"]
+	require.True(t, ok, "missing debug stack field")
+	debugStackStr, ok := debugStackI.(string)
+	require.True(t, ok, "invalid debug stack type")
+	assert.Contains(t, debugStackStr, a1000)
+	assert.Contains(t, debugStackStr, strings.Repeat("b", 24))
+}
+
+// TestRecovererLogStack_ParseDebugStackLimit is testing if the debug_stack string cut was successful
+// if the limit is greater than the length of the debug_stack
+func TestRecovererLogStack_ParseDebugStackLimit2(t *testing.T) {
+	ls := RecovererLogStack{DebugStackLengthLimit: 1024}
+	a100 := strings.Repeat("a", 100)
+	b100 := strings.Repeat("b", 100)
+	parse, err := ls.Parse(context.Background(), []byte(a100+b100), errors.New("some panic"))
+	require.NoError(t, err)
+	var labels map[string]interface{}
+	require.NoError(t, json.Unmarshal(parse, &labels))
+	debugStackI, ok := labels["debug_stack"]
+	require.True(t, ok, "missing debug stack field")
+	debugStackStr, ok := debugStackI.(string)
+	require.True(t, ok, "invalid debug stack type")
+	assert.Contains(t, debugStackStr, a100)
+	assert.Contains(t, debugStackStr, b100)
+}
+
 type custom struct{}
 
 func (c custom) Parse(_ context.Context, debugStack []byte, rvr interface{}) ([]byte, error) {