♲ 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_*)

cli/drop.go

@@ -42,8 +42,9 @@ var DropCmd = &cobra.Command{
 	Args:         cobra.ExactArgs(2),
 	SilenceUsage: true,
 	RunE: func(cmd *cobra.Command, args []string) error {
+		v, _ := config.RetrieveFromContext(cmd.Context())
 		if outJson {
-			config.Overrides["output.stdout.config.format"] = "json"
+			v.Set("output.stdout.config.format", "json")
 		}
 
 		log := args[0]
@@ -60,12 +61,12 @@ var DropCmd = &cobra.Command{
 		}
 		e := models.Entry{Title: title, Date: d.Time(), Fields: *ms}
 		l := models.Log{Name: log, Entries: []models.Entry{e}}
-		err := files.Append(l)
+		err := files.Append(cmd.Context(), l)
 		if err != nil {
 			return err
 		}
 
-		form, err := formatters.Preferred()
+		form, err := formatters.Preferred(cmd.Context())
 		if err != nil {
 			return err
 		}