Merge pull request #1187 from smallstep/herman/fix-stack-trace-error-logging

Fix `StackTracedError` logging

api/log/log.go

@@ -7,8 +7,6 @@ import (
 	"os"
 
 	"github.com/pkg/errors"
-
-	"github.com/smallstep/certificates/logging"
 )
 
 // StackTracedError is the set of errors implementing the StackTrace function.
@@ -21,16 +19,21 @@ type StackTracedError interface {
 	StackTrace() errors.StackTrace
 }
 
+type fieldCarrier interface {
+	WithFields(map[string]any)
+	Fields() map[string]any
+}
+
 // Error adds to the response writer the given error if it implements
 // logging.ResponseLogger. If it does not implement it, then writes the error
 // using the log package.
 func Error(rw http.ResponseWriter, err error) {
-	rl, ok := rw.(logging.ResponseLogger)
+	fc, ok := rw.(fieldCarrier)
 	if !ok {
 		return
 	}
 
-	rl.WithFields(map[string]interface{}{
+	fc.WithFields(map[string]any{
 		"error": err,
 	})
 
@@ -39,8 +42,8 @@ func Error(rw http.ResponseWriter, err error) {
 	}
 
 	var st StackTracedError
-	if !errors.As(err, &st) {
+	if errors.As(err, &st) {
-		rl.WithFields(map[string]interface{}{
+		fc.WithFields(map[string]any{
 			"stack-trace": fmt.Sprintf("%+v", st.StackTrace()),
 		})
 	}
@@ -48,9 +51,9 @@ func Error(rw http.ResponseWriter, err error) {
 
 // EnabledResponse log the response object if it implements the EnableLogger
 // interface.
-func EnabledResponse(rw http.ResponseWriter, v interface{}) {
+func EnabledResponse(rw http.ResponseWriter, v any) {
 	type enableLogger interface {
-		ToLog() (interface{}, error)
+		ToLog() (any, error)
 	}
 
 	if el, ok := v.(enableLogger); ok {
@@ -61,8 +64,8 @@ func EnabledResponse(rw http.ResponseWriter, v interface{}) {
 			return
 		}
 
-		if rl, ok := rw.(logging.ResponseLogger); ok {
+		if rl, ok := rw.(fieldCarrier); ok {
-			rl.WithFields(map[string]interface{}{
+			rl.WithFields(map[string]any{
 				"response": out,
 			})
 		}

api/log/log_test.go

@@ -1,43 +1,78 @@
 package log
 
 import (
-	"errors"
 	"net/http"
 	"net/http/httptest"
-	"reflect"
 	"testing"
+	"unsafe"
+
+	pkgerrors "github.com/pkg/errors"
+	"github.com/stretchr/testify/assert"
 
 	"github.com/smallstep/certificates/logging"
 )
 
-func TestError(t *testing.T) {
+type stackTracedError struct{}
-	theError := errors.New("the error")
 
-	type args struct {
+func (stackTracedError) Error() string {
-		rw  http.ResponseWriter
+	return "a stacktraced error"
-		err error
+}
+
+func (stackTracedError) StackTrace() pkgerrors.StackTrace {
+	f := struct{}{}
+	return pkgerrors.StackTrace{ // fake stacktrace
+		pkgerrors.Frame(unsafe.Pointer(&f)),
+		pkgerrors.Frame(unsafe.Pointer(&f)),
 	}
+}
+
+func TestError(t *testing.T) {
 	tests := []struct {
 		name string
-		args       args
+		error
-		withFields bool
+		rw               http.ResponseWriter
+		isFieldCarrier   bool
+		stepDebug        bool
+		expectStackTrace bool
 	}{
-		{"normalLogger", args{httptest.NewRecorder(), theError}, false},
+		{"noLogger", nil, nil, false, false, false},
-		{"responseLogger", args{logging.NewResponseLogger(httptest.NewRecorder()), theError}, true},
+		{"noError", nil, logging.NewResponseLogger(httptest.NewRecorder()), true, false, false},
+		{"noErrorDebug", nil, logging.NewResponseLogger(httptest.NewRecorder()), true, true, false},
+		{"anError", assert.AnError, logging.NewResponseLogger(httptest.NewRecorder()), true, false, false},
+		{"anErrorDebug", assert.AnError, logging.NewResponseLogger(httptest.NewRecorder()), true, true, false},
+		{"stackTracedError", new(stackTracedError), logging.NewResponseLogger(httptest.NewRecorder()), true, true, true},
+		{"stackTracedErrorDebug", new(stackTracedError), logging.NewResponseLogger(httptest.NewRecorder()), true, true, true},
 	}
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			Error(tt.args.rw, tt.args.err)
+			if tt.stepDebug {
-			if tt.withFields {
+				t.Setenv("STEPDEBUG", "1")
-				if rl, ok := tt.args.rw.(logging.ResponseLogger); ok {
-					fields := rl.Fields()
-					if !reflect.DeepEqual(fields["error"], theError) {
-						t.Errorf("ResponseLogger[\"error\"] = %s, wants %s", fields["error"], theError)
-					}
 			} else {
-					t.Error("ResponseWriter does not implement logging.ResponseLogger")
+				t.Setenv("STEPDEBUG", "0")
 			}
+
+			Error(tt.rw, tt.error)
+
+			// return early if test case doesn't use logger
+			if !tt.isFieldCarrier {
+				return
+			}
+
+			fields := tt.rw.(logging.ResponseLogger).Fields()
+
+			// expect the error field to be (not) set and to be the same error that was fed to Error
+			if tt.error == nil {
+				assert.Nil(t, fields["error"])
+			} else {
+				assert.Same(t, tt.error, fields["error"])
+			}
+
+			// check if stack-trace is set when expected
+			if _, hasStackTrace := fields["stack-trace"]; tt.expectStackTrace && !hasStackTrace {
+				t.Error(`ResponseLogger["stack-trace"] not set`)
+			} else if !tt.expectStackTrace && hasStackTrace {
+				t.Error(`ResponseLogger["stack-trace"] was set`)
 			}
 		})
 	}