Removed the use of function types.

Function types are a little weird in that you need to cast functions to them *sometimes*.  Simpler to just leave them as raw function signatures.

Author: Russ Egan

v2/config_from_env.go

@@ -78,39 +78,43 @@ func UnmarshalEnv(o *HandlerOptions, envvars ...string) error {
 
 var handlerFns sync.Map
 
-func init() { //nolint:gochecknoinits
-	resetBuiltInHandlerFns()
-}
+var initHandlerFnsOnce sync.Once
 
 func resetBuiltInHandlerFns() {
 	handlerFns = sync.Map{}
 	textHandlerFn := func(_ string, w io.Writer, opts *slog.HandlerOptions) slog.Handler {
 		return slog.NewTextHandler(w, opts)
 	}
-	RegisterHandlerFn(TextHandler, textHandlerFn)
+	handlerFns.Store(TextHandler, textHandlerFn)
 	// for v1 compatibility, "console" is an alias for "text"
-	RegisterHandlerFn(ConsoleHandler, textHandlerFn)
-	RegisterHandlerFn(JSONHandler, func(_ string, w io.Writer, opts *slog.HandlerOptions) slog.Handler {
+	handlerFns.Store(ConsoleHandler, textHandlerFn)
+	handlerFns.Store(JSONHandler, func(_ string, w io.Writer, opts *slog.HandlerOptions) slog.Handler {
 		return slog.NewJSONHandler(w, opts)
 	})
-	RegisterHandlerFn(TermHandler, termHandlerFn(false))
-	RegisterHandlerFn(TermColorHandler, termHandlerFn(true))
-	RegisterHandlerFn(NoopHandler, func(_ string, _ io.Writer, _ *slog.HandlerOptions) slog.Handler {
+	handlerFns.Store(TermHandler, termHandlerFn(false))
+	handlerFns.Store(TermColorHandler, termHandlerFn(true))
+	handlerFns.Store(NoopHandler, func(_ string, _ io.Writer, _ *slog.HandlerOptions) slog.Handler {
 		return noop
 	})
 }
 
-func LookupHandlerFn(name string) HandlerFn {
+func initHandlerFns() {
+	initHandlerFnsOnce.Do(func() {
+		resetBuiltInHandlerFns()
+	})
+}
+
+func LookupHandlerFn(name string) func(string, io.Writer, *slog.HandlerOptions) slog.Handler {
+	initHandlerFns()
 	v, ok := handlerFns.Load(name)
 	if !ok {
 		return nil
 	}
-	return v.(HandlerFn) //nolint:forcetypeassert // if it's not a HandlerFn, we should panic
+	return v.(func(string, io.Writer, *slog.HandlerOptions) slog.Handler) //nolint:forcetypeassert // if it's not a HandlerFn, we should panic
 }
 
-type HandlerFn func(string, io.Writer, *slog.HandlerOptions) slog.Handler
-
-func RegisterHandlerFn(name string, fn HandlerFn) {
+func RegisterHandlerFn(name string, fn func(string, io.Writer, *slog.HandlerOptions) slog.Handler) {
+	initHandlerFns()
 	if fn == nil {
 		panic(fmt.Sprintf("constructor for sink %q is nil", name))
 	}
@@ -120,7 +124,7 @@ func RegisterHandlerFn(name string, fn HandlerFn) {
 	handlerFns.Store(name, fn)
 }
 
-func termHandlerFn(color bool) HandlerFn {
+func termHandlerFn(color bool) func(string, io.Writer, *slog.HandlerOptions) slog.Handler {
 	return func(_ string, w io.Writer, opts *slog.HandlerOptions) slog.Handler {
 		if opts == nil {
 			opts = &slog.HandlerOptions{}
@@ -131,7 +135,7 @@ func termHandlerFn(color bool) HandlerFn {
 			Theme:              console.NewDefaultTheme(),
 			ReplaceAttr:        opts.ReplaceAttr,
 			TimeFormat:         "15:04:05.000",
-			HeaderFormat:       "%t %[logger]12h %l | %m",
+			HeaderFormat:       "%t %[" + LoggerKey + "]8h %l | %m",
 			TruncateSourcePath: 2,
 		})
 	}

v2/config_from_env_test.go

@@ -200,7 +200,7 @@ func TestRegisterHandlerFn(t *testing.T) {
 	tests := []struct {
 		name        string
 		handlerName string
-		handlerFn   HandlerFn
+		handlerFn   func(string, io.Writer, *slog.HandlerOptions) slog.Handler
 		want        string
 		wantPanic   bool
 	}{
@@ -259,8 +259,8 @@ func TestRegisterHandlerFn(t *testing.T) {
 	}
 
 	builtIns := map[string]string{
-		TermHandler:      "blue         INF | hi\n",
-		TermColorHandler: "\x1b[1;90mblue        \x1b[0m \x1b[32mINF\x1b[0m \x1b[1;90m|\x1b[0m \x1b[1mhi\x1b[0m\n",
+		TermHandler:      "blue     INF | hi\n",
+		TermColorHandler: "\x1b[1;90mblue    \x1b[0m \x1b[32mINF\x1b[0m \x1b[1;90m|\x1b[0m \x1b[1mhi\x1b[0m\n",
 		TextHandler:      "level=INFO msg=hi logger=blue\n",
 		JSONHandler:      `{"level":"INFO","msg":"hi","logger":"blue"}` + "\n",
 		ConsoleHandler:   "level=INFO msg=hi logger=blue\n",

v2/default.go

@@ -3,6 +3,7 @@ package flume
 import (
 	"log/slog"
 	"math"
+	"sync"
 )
 
 const (
@@ -29,14 +30,19 @@ func New(name string) *slog.Logger {
 	return slog.New(Default().Named(name))
 }
 
-var defaultHandler = NewHandler(nil, &HandlerOptions{
-	HandlerFn: LookupHandlerFn(NoopHandler),
-})
+var defaultHandler *Handler
+
+var initDefaultHandlerOnce sync.Once
 
 // Default returns the default Handler.  It will never be
 // nil.  By default, it is a noop handler that discards all log messages.
 //
 // The simplest way to enable logging is to call Default().SetHandlerOptions(nil)
 func Default() *Handler {
+	initDefaultHandlerOnce.Do(func() {
+		defaultHandler = NewHandler(nil, &HandlerOptions{
+			HandlerFn: LookupHandlerFn(NoopHandler),
+		})
+	})
 	return defaultHandler
 }

v2/default_test.go

@@ -8,6 +8,16 @@ import (
 
 func TestNew(t *testing.T) {
 	tests := []handlerTest{
+		{
+			// this is a bit of a hack to test that the default handler is a noop handler
+			// for the very first test, the test loop will not configure the default handler,
+			// so it should be a noop handler
+			name: "default noop",
+			handlerFn: func(_ *bytes.Buffer) slog.Handler {
+				return Default()
+			},
+			want: "",
+		},
 		{
 			name: "New",
 			handlerFn: func(_ *bytes.Buffer) slog.Handler {
@@ -20,15 +30,24 @@ func TestNew(t *testing.T) {
 			handlerFn: func(_ *bytes.Buffer) slog.Handler {
 				h := Default()
 				// need something to trigger rebuilding the handlers
-				// so the captured stdout is correct
+				// the test is will have replaced os.Stdout, but the default handler
+				// is still writing to the old os.Stdout
 				h.SetOut(nil)
 				return h
 			},
 			want: "level=INFO msg=hi\n",
 		},
 	}
-	for _, tt := range tests {
-		tt.stdout = true
-		tt.Run(t)
+	for i, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if i != 0 {
+				ogOpts := Default().HandlerOptions()
+				defer Default().SetHandlerOptions(ogOpts)
+
+				Default().SetHandlerOptions(nil)
+			}
+			tt.stdout = true
+			tt.Run(t)
+		})
 	}
 }