♲ Refactor configuration to use viper with context propagation

- Replace global ConfigPath and Overrides with viper-based configuration
- Add viper.New() to create configurable viper instances
- Store viper and unmarshaled Config struct in context for testability
- Add RetrieveFromContext and AddToContext helper functions
- Update files.Append to accept context and retrieve config from it
- Update formatters.Preferred and formatters.New to accept context
- Add PersistentPreRunE in CLI to create and configure viper instance
- Support -c flag for custom config file path
- Support -v flag for config value overrides
- Update all test files to create viper and add to context
- Remove unused config types and load functions
- Add viper as dependency with automatic env var support (MYLOG_*)

formatters/new.go

@@ -1,12 +1,13 @@
 package formatters
 
 import (
+	"context"
 	"errors"
 
 	"codeberg.org/danjones000/my-log/config"
 )
 
-type formatMaker func(config.Formatters) (Formatter, error)
+type formatMaker func(config map[string]any) (Formatter, error)
 
 var formatterMap = map[string]formatMaker{
 	"plain": newPlain,
@@ -14,23 +15,22 @@ var formatterMap = map[string]formatMaker{
 	"zero":  newNull,
 }
 
-func Preferred() (f Formatter, err error) {
-	conf, err := config.Load()
-	if err != nil {
-		return
-	}
-	std, _ := conf.Outputs.Stdout()
-	return New(std.Format)
+func Preferred(ctx context.Context) (f Formatter, err error) {
+	v, _ := config.RetrieveFromContext(ctx)
+	format := v.GetString("output.stdout.config.format")
+	return New(ctx, format)
 }
 
-func New(kind string) (f Formatter, err error) {
-	conf, err := config.Load()
-	if err != nil {
-		return
-	}
+func New(ctx context.Context, kind string) (f Formatter, err error) {
+	_, c := config.RetrieveFromContext(ctx)
+	conf := c.Formatters
 
 	if make, ok := formatterMap[kind]; ok {
-		return make(conf.Formatters)
+		var formatterConf map[string]any
+		if cf, ok := conf[kind]; ok {
+			formatterConf = cf
+		}
+		return make(formatterConf)
 	}
 
 	return nil, errors.New("unimplemented")