Added a bunch more methods to Controller

Allows more granualar manipulation of levels, sinks, and middleware, as well as ways to get the current values, and to replace all of the values atomically.

Also increased test coverage.

Author: Russ Egan

v2/TODO.md

@@ -36,7 +36,7 @@
         *can* do this if they wish, by first setting a new default sink, then setting slog's default handler, but that there are caveats.
       - or should v2 act like v1 and not log anything until it has been configured?  Should there be an option to buffer until a configuration
         has been set, so logs won't be lost?
-- [ ] When using Config to set all the levels, does that clear any prior level settings?  Is there generally a way to clear/reset
+- [x] When using Config to set all the levels, does that clear any prior level settings?  Is there generally a way to clear/reset
       all confs?
 - [ ] Should there be a bridge from v1 to v2?  Add a way to direct all v1 calls to v2 calls?
   - Working on a slog handler -> zap core bridge, and a zap core -> slog handler bridge

v2/conf.go

@@ -17,8 +17,8 @@ type conf struct {
 	globalMiddleware []Middleware
 }
 
-func (c *conf) setSink(sink slog.Handler, isDefault bool) {
-	if c.customSink && isDefault {
+func (c *conf) setSink(sink slog.Handler, isDefault, replace bool) {
+	if !replace && c.customSink && isDefault {
 		return
 	}
 
@@ -50,27 +50,23 @@ func (c *conf) rebuildDelegate() {
 	c.delegatePtr.Store(&h)
 }
 
-func (c *conf) setLevel(l slog.Level, isDefault bool) {
-	// don't need a mutex here.  this is already protected
-	// by the Controller mutex, and the `lvl` pointer itself
-	// is immutable.
-	switch {
-	case isDefault && !c.customLvl:
-		c.lvl.Set(l)
-	case !isDefault:
-		c.customLvl = true
-		c.lvl.Set(l)
+func (c *conf) setLevel(l slog.Level, isDefault, replace bool) {
+	if !replace && c.customLvl && isDefault {
+		return
 	}
-}
 
-func (c *conf) use(middleware ...Middleware) {
-	c.middleware = append(c.middleware, middleware...)
+	c.customLvl = !isDefault
 
-	c.rebuildDelegate()
+	c.lvl.Set(l)
 }
 
-func (c *conf) setGlobalMiddleware(middleware []Middleware) {
-	c.globalMiddleware = middleware
+func (c *conf) use(global []Middleware, replace bool, local ...Middleware) {
+	c.globalMiddleware = global
+	if replace {
+		c.middleware = local
+	} else {
+		c.middleware = append(c.middleware, local...)
+	}
 
 	c.rebuildDelegate()
 }

v2/config.go

@@ -27,7 +27,12 @@ const (
 	TermColorSink = "term-color"
 )
 
-func init() {
+func init() { //nolint:gochecknoinits
+	resetBuiltInSinks()
+}
+
+func resetBuiltInSinks() {
+	sinkConstructors = sync.Map{}
 	RegisterSinkConstructor(TextSink, textSinkConstructor)
 	// for v1 compatibility, "console" is an alias for "text"
 	RegisterSinkConstructor(ConsoleSink, textSinkConstructor)
@@ -37,6 +42,12 @@ func init() {
 }
 
 func RegisterSinkConstructor(name string, constructor SinkConstructor) {
+	if constructor == nil {
+		panic(fmt.Sprintf("constructor for sink %q is nil", name))
+	}
+	if name == "" {
+		panic("constructor registered with empty name")
+	}
 	sinkConstructors.Store(name, constructor)
 }
 
@@ -144,16 +155,9 @@ type Config struct {
 	ReplaceAttrs []func([]string, slog.Attr) slog.Attr
 }
 
-const (
-	EncodingJSON      = "json"
-	EncodingText      = "text"
-	EncodingTerm      = "term"
-	EncodingTermColor = "term-color"
-)
-
 func DevDefaults() Config {
 	return Config{
-		DefaultSink: "term-color",
+		DefaultSink: TermColorSink,
 		AddSource:   true,
 	}
 }
@@ -181,9 +185,10 @@ func parseLevel(v any) (slog.Level, error) {
 	case string:
 		s = v
 	case float64:
-		// allow raw integer values for level
+		// allow numbers to be used as level values
 		return slog.Level(v), nil
 	case int:
+		// allow raw integer values for level
 		return slog.Level(v), nil
 	case bool:
 		if v {
@@ -290,7 +295,7 @@ func (c *Config) UnmarshalJSON(bytes []byte) error {
 			}
 		}
 	default:
-		return merry.Errorf("invalid level value: %v", s.Levels)
+		return merry.Errorf("invalid levels value: %v", s.Levels)
 	}
 
 	// for backward compat with v1, allow "addCaller" as
@@ -339,16 +344,27 @@ func (c Config) Handler() (slog.Handler, error) {
 	if !ok {
 		return nil, errors.New("unknown sink constructor: " + c.DefaultSink)
 	}
-	constructor := v.(SinkConstructor)
+	constructor, _ := v.(SinkConstructor)
 	return constructor(c)
 }
 
+// Controller returns a new controller configured with the given config.
+func (c Config) Controller() (*Controller, error) {
+	ctl := NewController(nil)
+	err := c.Configure(ctl)
+	if err != nil {
+		return nil, err
+	}
+	return ctl, nil
+}
+
+// Configure configures a controller with the given config.
+//
+// It sets the default level, levels, and sink.  Level settings
+// replace any current level settings.
 func (c Config) Configure(ctl *Controller) error {
 	ctl.SetDefaultLevel(c.DefaultLevel)
-
-	for name, level := range c.Levels {
-		ctl.SetLevel(name, level)
-	}
+	ctl.SetLevels(c.Levels, true)
 
 	h, err := c.Handler()
 	if err != nil {