feat: unify generated configuration loading and extensible decoders

config/file.go

@@ -1,100 +1,16 @@
 package config
 
 import (
-	"bytes"
 	"context"
-	"encoding/json"
 	"errors"
-	"io"
-	"os"
-	"path/filepath"
 	"reflect"
 	"strings"
 	"sync"
 	"time"
 
-	apierrors "git.yuntuo.hk/k2safe/go-omni/errors"
 	"git.yuntuo.hk/k2safe/go-omni/logx"
-	"gopkg.in/yaml.v3"
 )
 
-// DecodeFile merges a bounded JSON/YAML document into defaults. It uses JSON
-// field names for both formats, rejects unknown fields and accepts durations
-// such as "3s". Application-specific validation remains with the caller.
-func DecodeFile[T any](path string, defaults T) (T, error) {
-	result, err := decodeFile(path, defaults)
-	if err != nil {
-		var zero T
-		return zero, &DecodeError{cause: err}
-	}
-	return result, nil
-}
-
-// DecodeError keeps input values out of public diagnostics while preserving
-// errors.Is/As for explicitly handled underlying I/O and syntax errors.
-type DecodeError struct{ cause error }
-
-func (e *DecodeError) Error() string {
-	return "config: cannot decode file; check its path, format, field names and value types"
-}
-func (e *DecodeError) Unwrap() error { return e.cause }
-func decodeFile[T any](path string, defaults T) (T, error) {
-	var zero T
-	f, err := os.Open(path)
-	if err != nil {
-		return zero, err
-	}
-	defer f.Close()
-	data, err := io.ReadAll(io.LimitReader(f, (1<<20)+1))
-	if err != nil {
-		return zero, err
-	}
-	if len(data) > 1<<20 {
-		return zero, errors.New("config: file exceeds 1 MiB")
-	}
-	var value any
-	switch strings.ToLower(filepath.Ext(path)) {
-	case ".yaml", ".yml":
-		dec := yaml.NewDecoder(bytes.NewReader(data))
-		if err := dec.Decode(&value); err != nil {
-			return zero, err
-		}
-		var extra any
-		if err := dec.Decode(&extra); err != io.EOF {
-			return zero, errors.New("config: one YAML document required")
-		}
-	case ".json":
-		if err := apierrors.DecodeCatalogJSON(data, &value); err != nil {
-			return zero, err
-		}
-	default:
-		return zero, errors.New("config: expected .json, .yaml or .yml")
-	}
-	if _, ok := value.(map[string]any); !ok {
-		return zero, errors.New("config: root must be an object")
-	}
-	value, err = durations(value, reflect.TypeOf(defaults))
-	if err != nil {
-		return zero, err
-	}
-	encoded, err := json.Marshal(value)
-	if err != nil {
-		return zero, err
-	}
-	// Clone configuration without serializing borrowed json:"-" capabilities.
-	var result T
-	original, err := cloneConfiguration(reflect.ValueOf(&defaults).Elem(), 0)
-	if err != nil {
-		return zero, err
-	}
-	reflect.ValueOf(&result).Elem().Set(original)
-	dec := json.NewDecoder(bytes.NewReader(encoded))
-	dec.DisallowUnknownFields()
-	if err = dec.Decode(&result); err != nil {
-		return zero, err
-	}
-	return result, nil
-}
 func durations(v any, t reflect.Type) (any, error) {
 	if t == nil {
 		return v, nil