Added multistack logging

go.mod

@@ -1 +1,11 @@
 module github.com/rs/zerolog
+
+go 1.12
+
+require (
+	github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e
+	github.com/pkg/errors v0.8.1
+	github.com/rs/xid v1.2.1
+	github.com/zenazn/goji v0.9.0
+	golang.org/x/tools v0.0.0-20190321154406-ae772f11d294
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e h1:Wf6HqHfScWJN9/ZjdUKyjop4mf3Qdd+1TvvltAvM3m8=
+github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/rs/xid v1.2.1 h1:mhH9Nq+C1fY2l1XIpgxIiUOfNpRBYH1kKcr+qfKgjRc=
+github.com/rs/xid v1.2.1/go.mod h1:+uKXf+4Djp6Md1KODXJxgGQPKngRmWyn10oCKFzNHOQ=
+github.com/zenazn/goji v0.9.0 h1:RSQQAbXGArQ0dIDEq+PI6WqN6if+5KHu6x2Cx/GXLTQ=
+github.com/zenazn/goji v0.9.0/go.mod h1:7S9M489iMyHBNxwZnk9/EHS098H4/F6TATF2mIxtB1Q=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20190321154406-ae772f11d294 h1:gMPF/7U3xs3RNmp7bh9BoJnRg81e5uKSYpyaGoAmadw=
+golang.org/x/tools v0.0.0-20190321154406-ae772f11d294/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=

pkgerrors/stacktrace.go

@@ -40,13 +40,14 @@ func frameField(f errors.Frame, s *state, c rune) string {
 	return string(s.b)
 }
 
+type stackTracer interface {
+	StackTrace() errors.StackTrace
+}
+
 // MarshalStack implements pkg/errors stack trace marshaling.
 //
 //   zerolog.ErrorStackMarshaler = MarshalStack
 func MarshalStack(err error) interface{} {
-	type stackTracer interface {
-		StackTrace() errors.StackTrace
-	}
 	sterr, ok := err.(stackTracer)
 	if !ok {
 		return nil
@@ -63,3 +64,60 @@ func MarshalStack(err error) interface{} {
 	}
 	return out
 }
+
+type stackTrace struct {
+	Frames []frame `json:"stacktrace"`
+}
+
+type frame struct {
+	StackSourceFileName string `json:"source"`
+	StackSourceLineName string `json:"line"`
+	StackSourceFuncName string `json:"func"`
+}
+
+// MarshalMultiStack properly implements pkg/errors stack trace marshaling by unwrapping the error stack.
+//
+//   zerolog.ErrorStackMarshaler = MarshalMultiStack
+func MarshalMultiStack(err error) interface{} {
+	stackTraces := []stackTrace{}
+	currentErr := err
+	for currentErr != nil {
+		stack, ok := currentErr.(stackTracer)
+		if !ok {
+			// Unwrap again because errors.Wrap actually adds two
+			// layers of wrapping.
+			currentErr = unwrapErr(currentErr)
+			continue
+		}
+		st := stack.StackTrace()
+		s := &state{}
+		stackTrace := stackTrace{}
+		for _, f := range st {
+			frame := frame{
+				StackSourceFileName: frameField(f, s, 's'),
+				StackSourceLineName: frameField(f, s, 'd'),
+				StackSourceFuncName: frameField(f, s, 'n'),
+			}
+			stackTrace.Frames = append(stackTrace.Frames, frame)
+		}
+		stackTraces = append(stackTraces, stackTrace)
+
+		currentErr = unwrapErr(currentErr)
+	}
+	return stackTraces
+}
+
+type causer interface {
+	Cause() error
+}
+
+// Some methods of wrapping cause more layers of wrapping than other layers,
+// e.g. errors.New, errors.WithStack and errors.WithMessage add one layer of
+// wrapping, whereas errors.Wrap adds two layers of wrapping.
+func unwrapErr(err error) error {
+	cause, ok := err.(causer)
+	if !ok {
+		return nil
+	}
+	return cause.Cause()
+}

pkgerrors/stacktrace_test.go

@@ -27,6 +27,24 @@ func TestLogStack(t *testing.T) {
 	}
 }
 
+func TestLogMultiStack(t *testing.T) {
+	zerolog.ErrorStackMarshaler = MarshalMultiStack
+
+	out := &bytes.Buffer{}
+	log := zerolog.New(out)
+
+	err := errors.New("error message")
+	err = errors.Wrap(err, "from error")
+	log.Log().Stack().Err(err).Msg("")
+
+	got := out.String()
+	want := `\{"stack":\[\{"stacktrace":\[\{"source":"stacktrace_test.go","line":"37","func":"TestLogMultiStack"\},.*\{"stacktrace":\[\{"source":"stacktrace_test.go","line":"36","func":"TestLogMultiStack"\}.*\],"error":"from error: error message"\}`
+	if ok, _ := regexp.MatchString(want, got); !ok {
+		t.Errorf("invalid log output:\ngot:  %v\nwant: %v", got, want)
+	}
+
+}
+
 func BenchmarkLogStack(b *testing.B) {
 	zerolog.ErrorStackMarshaler = MarshalStack
 	out := &bytes.Buffer{}