From f9cac8fbe028511c73c4eddb5fe8aad25dd2557a Mon Sep 17 00:00:00 2001
From: Masayoshi Mizutani <masayoshi.mizutani@dr-ubie.com>
Date: Sat, 12 Aug 2023 12:50:50 +0900
Subject: [PATCH] Add slog.LogValuer interface

---
 errors.go                | 28 ++++++++++++++++++++++++++++
 examples/logging/main.go | 25 +++++++++++++++++++++++++
 go.mod                   |  7 +++++--
 go.sum                   |  2 ++
 go.work                  |  2 +-
 test/go.mod              |  2 +-
 6 files changed, 62 insertions(+), 4 deletions(-)
 create mode 100644 examples/logging/main.go

diff --git a/errors.go b/errors.go
index 21e542c..bdcc788 100644
--- a/errors.go
+++ b/errors.go
@@ -6,6 +6,8 @@ import (
 	"io"
 	"strings"
 
+	"log/slog"
+
 	"github.com/google/uuid"
 )
 
@@ -182,3 +184,29 @@ func (x *Error) Values() map[string]any {
 
 	return values
 }
+
+func (x *Error) LogValue() slog.Value {
+	attrs := []slog.Attr{
+		slog.String("message", x.msg),
+	}
+	var values []any
+	for k, v := range x.values {
+		values = append(values, slog.Any(k, v))
+	}
+	attrs = append(attrs, slog.Group("values", values...))
+
+	var stacktrace any
+	var traces []string
+	for _, st := range x.StackTrace() {
+		traces = append(traces, fmt.Sprintf("%s:%d %s", st.file(), st.line(), st.name()))
+	}
+	stacktrace = traces
+
+	attrs = append(attrs, slog.Any("stacktrace", stacktrace))
+
+	if x.cause != nil {
+		attrs = append(attrs, slog.Any("cause", x.cause))
+	}
+
+	return slog.GroupValue(attrs...)
+}
diff --git a/examples/logging/main.go b/examples/logging/main.go
new file mode 100644
index 0000000..9470c3c
--- /dev/null
+++ b/examples/logging/main.go
@@ -0,0 +1,25 @@
+package main
+
+import (
+	"os"
+
+	"log/slog"
+
+	"github.com/m-mizutani/goerr"
+)
+
+var runtimeError = goerr.New("runtime error")
+
+func someAction(input string) error {
+	if input != "OK" {
+		return goerr.Wrap(runtimeError, "input is not OK").With("input", input)
+	}
+	return nil
+}
+
+func main() {
+	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
+	if err := someAction("ng"); err != nil {
+		logger.Error("fail someAction", slog.Any("error", err))
+	}
+}
diff --git a/go.mod b/go.mod
index a61b381..6717d70 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,8 @@
 module github.com/m-mizutani/goerr
 
-go 1.18
+go 1.21
 
-require github.com/google/uuid v1.3.0
+require (
+	github.com/google/uuid v1.3.0
+	golang.org/x/exp v0.0.0-20230810033253-352e893a4cad
+)
diff --git a/go.sum b/go.sum
index 3dfe1c9..9e1e4ba 100644
--- a/go.sum
+++ b/go.sum
@@ -1,2 +1,4 @@
 github.com/google/uuid v1.3.0 h1:t6JiXgmwXMjEs8VusXIJk2BXHsn+wx8BZdTaoZ5fu7I=
 github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+golang.org/x/exp v0.0.0-20230810033253-352e893a4cad h1:g0bG7Z4uG+OgH2QDODnjp6ggkk1bJDsINcuWmJN1iJU=
+golang.org/x/exp v0.0.0-20230810033253-352e893a4cad/go.mod h1:FXUEEKJgO7OQYeo8N01OfiKP8RXMtf6e8aTskBGqWdc=
diff --git a/go.work b/go.work
index c3d2fb0..dc94c8f 100644
--- a/go.work
+++ b/go.work
@@ -1,4 +1,4 @@
-go 1.18
+go 1.21
 
 use (
 	.
diff --git a/test/go.mod b/test/go.mod
index f9eae03..5bd59ce 100644
--- a/test/go.mod
+++ b/test/go.mod
@@ -1,6 +1,6 @@
 module github.com/m-mizutani/goerr/test
 
-go 1.18
+go 1.21
 
 require (
 	github.com/m-mizutani/goerr v0.1.5