feat(logger): fallback to slog levels if no levels are specified (#10)

.slog.example.yml

@@ -32,7 +32,7 @@ attrs:
   - err: error
 
 # if present, a wrapper for slog.Logger is generated with a method for each level.
-# TODO: if no levels are specified, the builtin slog levels are used.
+# if no levels are specified, the builtin slog levels are used.
 logger:
   # the API style for methods.
   # possible values: [any, attr]

sloggen.go

@@ -17,28 +17,28 @@ import (
 var tmpl = template.Must(template.New("").Funcs(funcs).Parse(
 	`// Code generated by go-simpler.org/sloggen. DO NOT EDIT.
 
-package {{.Pkg}}
+package {{$.Pkg}}
 
-{{range .Imports -}}
+{{range $.Imports -}}
 import "{{.}}"
 {{end}}
 
-{{range .Levels -}}
+{{range $.Levels -}}
 const Level{{title .Name}} = slog.Level({{.Severity}})
 {{end}}
 
-{{range .Consts -}}
+{{range $.Consts -}}
 const {{snakeToCamel .}} = "{{.}}"
 {{end}}
 
-{{range .Attrs -}}
+{{range $.Attrs -}}
 func {{snakeToCamel .Key}}(value {{.Type}}) slog.Attr { return slog.{{slogFunc .Type}}("{{.Key}}", value) }
 {{end}}
 
-{{if .HasCustomLevels}}
+{{if $.HasCustomLevels}}
 func ParseLevel(s string) (slog.Level, error) {
 	switch strings.ToUpper(s) {
-	{{range .Levels -}}
+	{{range $.Levels -}}
 	case "{{upper .Name}}":
 		return Level{{title .Name}}, nil
 	{{end -}}
@@ -52,7 +52,7 @@ func ReplaceAttr(_ []string, attr slog.Attr) slog.Attr {
 		return attr
 	}
 	switch attr.Value.Any().(slog.Level) {
-	{{range .Levels -}}
+	{{range $.Levels -}}
 	case Level{{title .Name}}:
 		attr.Value = slog.StringValue("{{upper .Name}}")
 	{{end -}}
@@ -61,21 +61,21 @@ func ReplaceAttr(_ []string, attr slog.Attr) slog.Attr {
 }
 {{end}}
 
-{{if .Logger}}
+{{if $l := $.Logger}}
 type Logger struct{ Logger *slog.Logger }
-{{range .Levels}}
-func (l *Logger) {{title .Name}}({{if $.Logger.Context}}ctx context.Context, {{end}}msg string, {{if $.Logger.AttrAPI}}attrs ...slog.Attr{{else}}args ...any{{end}}) {
-	l.log({{if $.Logger.Context}}ctx{{else}}context.Background(){{end}}, Level{{title .Name}}, msg, {{if $.Logger.AttrAPI}}attrs{{else}}args{{end}})
+{{range $l.Levels}}
+func (l *Logger) {{title .Name}}({{if $l.Context}}ctx context.Context, {{end}}msg string, {{if $l.AttrAPI}}attrs ...slog.Attr{{else}}args ...any{{end}}) {
+	l.log({{if $l.Context}}ctx{{else}}context.Background(){{end}}, {{if not $.HasCustomLevels}}slog.{{end}}Level{{title .Name}}, msg, {{if $l.AttrAPI}}attrs{{else}}args{{end}})
 }
 {{end}}
-func (l *Logger) log(ctx context.Context, level slog.Level, msg string, {{if $.Logger.AttrAPI}}attrs []slog.Attr{{else}}args []any{{end}}) {
+func (l *Logger) log(ctx context.Context, level slog.Level, msg string, {{if $l.AttrAPI}}attrs []slog.Attr{{else}}args []any{{end}}) {
 	if !l.Logger.Enabled(ctx, level) {
 		return
 	}
 	var pcs [1]uintptr
 	runtime.Callers(3, pcs[:])
 	r := slog.NewRecord(time.Now(), level, msg, pcs[0])
-	r.Add{{if $.Logger.AttrAPI}}Attrs(attrs...){{else}}(args...){{end}}
+	r.Add{{if $l.AttrAPI}}Attrs(attrs...){{else}}(args...){{end}}
 	_ = l.Logger.Handler().Handle(ctx, r)
 }
 {{end}}`,
@@ -121,6 +121,7 @@ type (
 		Type string
 	}
 	logger struct {
+		Levels  []level
 		AttrAPI bool
 		Context bool
 	}
@@ -165,18 +166,34 @@ func readConfig(r io.Reader) (*config, error) {
 			cfg.HasCustomLevels = true
 		}
 	}
+	slices.SortFunc(cfg.Levels, func(l1, l2 level) int {
+		return cmp.Compare(l1.Severity, l2.Severity)
+	})
 
 	for i, m := range data.Attrs {
 		key, typ := getKV(m)
 		cfg.Attrs[i] = attr{key, typ}
 	}
+	slices.SortFunc(cfg.Attrs, func(a1, a2 attr) int {
+		return cmp.Compare(a1.Key, a2.Key)
+	})
 
 	if data.Logger != nil {
 		cfg.Logger = &logger{
+			Levels:  cfg.Levels,
 			AttrAPI: false,
 			Context: data.Logger.Context,
 		}
 
+		if len(cfg.Levels) == 0 {
+			cfg.Logger.Levels = []level{
+				{"debug", int(slog.LevelDebug)},
+				{"info", int(slog.LevelInfo)},
+				{"warn", int(slog.LevelWarn)},
+				{"error", int(slog.LevelError)},
+			}
+		}
+
 		switch data.Logger.API {
 		case "any":
 		case "attr":
@@ -196,16 +213,10 @@ func readConfig(r io.Reader) (*config, error) {
 		cfg.Imports = append(cfg.Imports, "context", "runtime")
 	}
 
-	slices.Sort(cfg.Imports)
 	slices.Sort(cfg.Consts)
-	slices.SortFunc(cfg.Levels, func(l1, l2 level) int {
-		return cmp.Compare(l1.Severity, l2.Severity)
-	})
-	slices.SortFunc(cfg.Attrs, func(a1, a2 attr) int {
-		return cmp.Compare(a1.Key, a2.Key)
-	})
-
+	slices.Sort(cfg.Imports)
 	cfg.Imports = slices.Compact(cfg.Imports)
+
 	return &cfg, nil
 }