feat: unify generated configuration loading and extensible decoders

config/project.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	apierrors "git.yuntuo.hk/k2safe/go-omni/errors"
+	"git.yuntuo.hk/k2safe/go-omni/logx"
 	"math"
 	"os"
 	"reflect"
@@ -34,30 +35,114 @@ func ApplyDefaults[T any](base T) (T, error) { return projectOverlay(base, EnvOp
 // LoadProject applies code/tag defaults, a strict optional file, environment,
 // then the project's Validate method, before any logger or dependency is opened.
 // envDefault is only applied to zero-valued defaults before reading the file.
-func LoadProject[T any](path string, defaults T, options EnvOptions) (T, error) {
+func LoadProject[T any](path string, defaults T, options EnvOptions, loaders ...*Loader) (T, error) {
 	var zero T
+	loader, err := selectLoader(loaders)
+	if err != nil {
+		return zero, err
+	}
 	cfg, err := projectOverlay(defaults, options, true)
 	if err != nil {
 		return zero, err
 	}
+	var doc Document
 	if path != "" {
-		cfg, err = DecodeFile(path, cfg)
+		doc, err = loader.read(path)
 		if err != nil {
-			return zero, errors.New("config: cannot decode file; check its path, format, field names and value types")
+			return zero, err
 		}
+		cfg, err = bindDocument(doc, cfg)
+		if err != nil {
+			return zero, locateError(err, path, doc, nil)
+		}
+	} else {
+		value, e := cloneConfiguration(reflect.ValueOf(&cfg).Elem(), 0)
+		if e != nil {
+			return zero, &Error{Reason: "cannot clone defaults", cause: e}
+		}
+		cfg = value.Interface().(T)
 	}
-	cfg, err = OverlayEnv(cfg, options)
+	origins := map[string]string{}
+	cfg, err = projectOverlay(cfg, options, false, origins)
 	if err != nil {
 		return zero, err
 	}
+	normalizeProject(reflect.ValueOf(&cfg).Elem(), "", origins, 0)
 	if valid, ok := any(&cfg).(interface{ Validate() error }); ok {
 		if err = valid.Validate(); err != nil {
-			return zero, err
+			return zero, locateError(err, path, doc, origins)
 		}
 	}
 	return cfg, nil
 }
 
+func locateError(err error, path string, doc Document, origins map[string]string) *Error {
+	d := validationError(err)
+	field := d.Field
+	for field != "" && origins[field] == "" {
+		index := strings.LastIndexAny(field, ".[")
+		if index < 0 {
+			field = ""
+		} else {
+			field = field[:index]
+		}
+	}
+	if env := origins[field]; env != "" {
+		d.Env = env
+		d.File = ""
+		d.Line = 0
+		d.Column = 0
+		return d
+	}
+	d.File = path
+	if d.Line == 0 {
+		p := doc.Positions[d.Field]
+		d.Line = p.Line
+		d.Column = p.Column
+	}
+	return d
+}
+
+// Framework-owned normalization stays inside the common pipeline. Explicit
+// environment stream selection clears a file profile unless a file override
+// was also provided; project code never needs to repeat this rule.
+func normalizeProject(v reflect.Value, path string, origins map[string]string, depth int) {
+	if depth > 32 {
+		return
+	}
+	if v.Kind() == reflect.Pointer {
+		if v.IsNil() {
+			return
+		}
+		v = v.Elem()
+	}
+	if v.Kind() != reflect.Struct {
+		return
+	}
+	if v.Type() == reflect.TypeOf(Config{}) && v.CanAddr() {
+		c := v.Addr().Interface().(*Config)
+		if origins[joinField(path, "log.output")] != "" && c.Log.Output != "" && (origins[joinField(path, "log.file")] == "" || c.Log.File == "") {
+			c.Log.File = ""
+			c.Log.Rotation = logx.RotationConfig{}
+		}
+		return
+	}
+	for i := 0; i < v.NumField(); i++ {
+		f := v.Type().Field(i)
+		if f.PkgPath != "" {
+			continue
+		}
+		name := strings.Split(f.Tag.Get("json"), ",")[0]
+		if name == "-" {
+			continue
+		}
+		if name == "" {
+			name = f.Name
+		}
+		normalizeProject(v.Field(i), joinField(path, name), origins, depth+1)
+	}
+}
+
 // OverlayEnv overlays the entire project struct without mutating the input.
 // Tags: env:"CUSTOM_NAME,required,secret,empty=reject"; env:"-" excludes a
 // subtree. required means nonempty string/non-nil pointer or collection; false
@@ -70,7 +155,7 @@ func OverlayEnv[T any](base T, options EnvOptions) (T, error) {
 var textType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
 var durationType = reflect.TypeOf(time.Duration(0))
 
-func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error) {
+func projectOverlay[T any](base T, options EnvOptions, defaults bool, sourceMaps ...map[string]string) (T, error) {
 	var zero T
 	if options.Lookup == nil {
 		options.Lookup = os.LookupEnv
@@ -88,8 +173,8 @@ func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error)
 	result := reflect.New(v.Type()).Elem()
 	result.Set(v)
 	seen := map[string]bool{}
-	var walk func(reflect.Value, string, int) error
-	walk = func(value reflect.Value, prefix string, depth int) error {
+	var walk func(reflect.Value, string, string, int) error
+	walk = func(value reflect.Value, prefix, path string, depth int) error {
 		if depth > 32 {
 			return errors.New("config: nesting exceeds 32")
 		}
@@ -110,6 +195,7 @@ func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error)
 			if jsonName == "" {
 				jsonName = field.Name
 			}
+			fieldPath := joinField(path, jsonName)
 			key := prefix + envName(jsonName)
 			if tag[0] != "" {
 				key = tag[0]
@@ -131,7 +217,7 @@ func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error)
 				}
 			}
 			if dst.Kind() == reflect.Struct && !dst.Addr().Type().Implements(textType) {
-				if err := walk(dst, key+"_", depth+1); err != nil {
+				if err := walk(dst, key+"_", fieldPath, depth+1); err != nil {
 					return err
 				}
 				continue
@@ -142,14 +228,14 @@ func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error)
 				if !dst.IsNil() {
 					child.Elem().Set(dst.Elem())
 				}
-				if err := walk(child.Elem(), key+"_", depth+1); err != nil {
+				if err := walk(child.Elem(), key+"_", fieldPath, depth+1); err != nil {
 					return err
 				}
 				if !dst.IsNil() || !child.Elem().IsZero() {
 					dst.Set(child)
 				}
 				if required && !defaults && dst.IsNil() {
-					return fmt.Errorf("config: %s is required", key)
+					return &Error{Env: key, Field: fieldPath, Reason: "is required"}
 				}
 				continue
 			}
@@ -164,7 +250,11 @@ func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error)
 				return fmt.Errorf("config: duplicate environment key %s", key)
 			}
 			seen[key] = true
-			raw, present := options.Lookup(key)
+			var raw string
+			var present bool
+			if !defaults {
+				raw, present = options.Lookup(key)
+			}
 			selectedKey := key
 			if !present && !defaults {
 				for _, alias := range options.Aliases[key] {
@@ -180,7 +270,7 @@ func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error)
 			}
 			if present && raw == "" && !defaults {
 				if empty == "reject" {
-					return fmt.Errorf("config: %s must not be empty", selectedKey)
+					return &Error{Env: selectedKey, Field: fieldPath, Reason: "must not be empty"}
 				}
 				if empty == "ignore" {
 					present = false
@@ -189,17 +279,24 @@ func projectOverlay[T any](base T, options EnvOptions, defaults bool) (T, error)
 			if present {
 				parsed := reflect.New(dst.Type()).Elem()
 				if err := parseEnvValue(parsed, raw); err != nil {
-					return fmt.Errorf("config: %s must be a valid %s", selectedKey, dst.Type())
+					origin := selectedKey
+					if defaults {
+						origin = ""
+					}
+					return &Error{Env: origin, Field: fieldPath, Reason: "expected a valid " + dst.Type().String(), cause: err}
 				}
 				dst.Set(parsed)
+				if !defaults && len(sourceMaps) > 0 {
+					sourceMaps[0][fieldPath] = selectedKey
+				}
 			}
 			if required && !defaults && emptyRequired(dst) {
-				return fmt.Errorf("config: %s is required", key)
+				return &Error{Env: key, Field: fieldPath, Reason: "is required"}
 			}
 		}
 		return nil
 	}
-	if err := walk(result, options.Prefix, 0); err != nil {
+	if err := walk(result, options.Prefix, "", 0); err != nil {
 		return zero, err
 	}
 	return result.Interface().(T), nil