refactor(errs): migrate from gperr.Error to standard Go error interface

This is a large-scale refactoring across the codebase that replaces the custom
`gperr.Error` type with Go's standard `error` interface. The changes include:

- Replacing `gperr.Error` return types with `error` in function signatures
- Using `errors.New()` and `fmt.Errorf()` instead of `gperr.New()` and `gperr.Errorf()`
- Using `%w` format verb for error wrapping instead of `.With()` method
- Replacing `gperr.Subject()` calls with `gperr.PrependSubject()`
- Converting error logging from `gperr.Log*()` functions to zerolog's `.Err().Msg()` pattern
- Update NewLogger to handle multiline error message
- Updating `goutils` submodule to latest commit

This refactoring aligns with Go idioms and removes the dependency on
custom error handling abstractions in favor of standard library patterns.

internal/route/rules/do.go

@@ -72,7 +72,7 @@ var commands = map[string]struct {
 			description: makeLines("Require HTTP authentication for incoming requests"),
 			args:        map[string]string{},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 0 {
 				return nil, ErrExpectNoArg
 			}
@@ -103,17 +103,17 @@ var commands = map[string]struct {
 				"to":   "the path to rewrite to, must start with /",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 2 {
 				return nil, ErrExpectTwoArgs
 			}
 			path1, err1 := validateURLPath(args[:1])
 			path2, err2 := validateURLPath(args[1:])
 			if err1 != nil {
-				err1 = gperr.Errorf("from: %w", err1)
+				err1 = gperr.PrependSubject(err1, "from")
 			}
 			if err2 != nil {
-				err2 = gperr.Errorf("to: %w", err2)
+				err2 = gperr.PrependSubject(err2, "to")
 			}
 			if err1 != nil || err2 != nil {
 				return nil, gperr.Join(err1, err2)
@@ -189,7 +189,7 @@ var commands = map[string]struct {
 				"route": "the route to route to",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 1 {
 				return nil, ErrExpectOneArg
 			}
@@ -227,7 +227,7 @@ var commands = map[string]struct {
 				"text": "the error message to return",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 2 {
 				return nil, ErrExpectTwoArgs
 			}
@@ -267,7 +267,7 @@ var commands = map[string]struct {
 				"realm": "the authentication realm",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) == 1 {
 				return args[0], nil
 			}
@@ -334,7 +334,7 @@ var commands = map[string]struct {
 				"value":  "the value to set",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			return validateModField(ModFieldSet, args)
 		},
 		build: func(args any) CommandHandler {
@@ -354,7 +354,7 @@ var commands = map[string]struct {
 				"value":  "the value to add",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			return validateModField(ModFieldAdd, args)
 		},
 		build: func(args any) CommandHandler {
@@ -373,7 +373,7 @@ var commands = map[string]struct {
 				"field":  "the field to remove",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			return validateModField(ModFieldRemove, args)
 		},
 		build: func(args any) CommandHandler {
@@ -398,7 +398,7 @@ var commands = map[string]struct {
 				"template": "the template to log",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 3 {
 				return nil, ErrExpectThreeArgs
 			}
@@ -455,7 +455,7 @@ var commands = map[string]struct {
 				"body":     "the body of the notification",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 4 {
 				return nil, ErrExpectFourArgs
 			}
@@ -543,7 +543,7 @@ func (cmd *Command) Parse(v string) error {
 		validArgs, err := builder.validate(args)
 		if err != nil {
 			// Only attach help for the directive that failed, avoid bringing in unrelated KV errors
-			return err.Subject(directive).With(builder.help.Error())
+			return gperr.PrependSubject(err, directive).With(builder.help.Error())
 		}
 
 		handler := builder.build(validArgs)

internal/route/rules/do_log_test.go

@@ -12,7 +12,6 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/yusing/godoxy/internal/serialization"
-	gperr "github.com/yusing/goutils/errs"
 )
 
 // mockUpstream creates a simple upstream handler for testing
@@ -32,7 +31,7 @@ func mockUpstreamWithHeaders(status int, body string, headers http.Header) http.
 	}
 }
 
-func parseRules(data string, target *Rules) gperr.Error {
+func parseRules(data string, target *Rules) error {
 	_, err := serialization.ConvertString(data, reflect.ValueOf(target))
 	return err
 }

internal/route/rules/do_set.go

@@ -6,7 +6,6 @@ import (
 	"net/url"
 	"strconv"
 
-	gperr "github.com/yusing/goutils/errs"
 	httputils "github.com/yusing/goutils/http"
 	ioutils "github.com/yusing/goutils/io"
 )
@@ -228,7 +227,7 @@ var modFields = map[string]struct {
 				"template": "the body template",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 1 {
 				return nil, ErrExpectOneArg
 			}
@@ -273,7 +272,7 @@ var modFields = map[string]struct {
 				"template": "the response body template",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 1 {
 				return nil, ErrExpectOneArg
 			}
@@ -301,7 +300,7 @@ var modFields = map[string]struct {
 				"code": "the status code",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 1 {
 				return nil, ErrExpectOneArg
 			}

internal/route/rules/error_format_test.go

@@ -3,7 +3,7 @@ package rules
 import (
 	"testing"
 
-	gperr "github.com/yusing/goutils/errs"
+	"github.com/rs/zerolog/log"
 )
 
 func TestErrorFormat(t *testing.T) {
@@ -19,5 +19,5 @@ func TestErrorFormat(t *testing.T) {
   do: set invalid_command
 - do: set resp_body "{{ .Request.Method {{ .Request.URL.Path }}"
 `, &rules)
-	gperr.LogError("error", err)
+	log.Err(err).Msg("error")
 }

internal/route/rules/help.go

@@ -131,7 +131,7 @@ Generate help string as error, e.g.
 		from: the path to rewrite, must start with /
 		to: the path to rewrite to, must start with /
 */
-func (h *Help) Error() gperr.Error {
+func (h *Help) Error() error {
 	var lines gperr.MultilineError
 
 	lines.Adds(ansi.WithANSI(h.command, ansi.HighlightGreen))

internal/route/rules/http_flow_test.go

@@ -17,7 +17,6 @@ import (
 	"github.com/yusing/godoxy/internal/route"
 	"github.com/yusing/godoxy/internal/route/routes"
 	"github.com/yusing/godoxy/internal/serialization"
-	gperr "github.com/yusing/goutils/errs"
 	"golang.org/x/crypto/bcrypt"
 
 	. "github.com/yusing/godoxy/internal/route/rules"
@@ -44,7 +43,7 @@ func mockRoute(alias string) *route.FileServer {
 	return &route.FileServer{Route: &route.Route{Alias: alias}}
 }
 
-func parseRules(data string, target *Rules) gperr.Error {
+func parseRules(data string, target *Rules) error {
 	_, err := serialization.ConvertString(strings.TrimSpace(data), reflect.ValueOf(target))
 	return err
 }

internal/route/rules/io.go

@@ -10,7 +10,6 @@ import (
 
 	"github.com/yusing/godoxy/internal/common"
 	"github.com/yusing/godoxy/internal/logging/accesslog"
-	gperr "github.com/yusing/goutils/errs"
 )
 
 type noopWriteCloser struct {
@@ -31,7 +30,7 @@ var (
 	testFilesLock sync.Mutex
 )
 
-func openFile(path string) (io.WriteCloser, gperr.Error) {
+func openFile(path string) (io.WriteCloser, error) {
 	switch path {
 	case "/dev/stdout":
 		return stdout, nil

internal/route/rules/on.go

@@ -59,7 +59,7 @@ var checkers = map[string]struct {
 			),
 			args: map[string]string{},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 0 {
 				return nil, ErrExpectNoArg
 			}
@@ -251,7 +251,7 @@ var checkers = map[string]struct {
 				"proto": "the http protocol (http, https, h3)",
 			},
 		},
-		validate: func(args []string) (any, gperr.Error) {
+		validate: func(args []string) (any, error) {
 			if len(args) != 1 {
 				return nil, ErrExpectOneArg
 			}
@@ -581,7 +581,7 @@ func (on *RuleOn) Parse(v string) error {
 		}
 		parsed, isResp, err := parseOn(rule)
 		if err != nil {
-			errs.Add(err.Subjectf("line %d", i+1))
+			errs.AddSubjectf(err, "line %d", i+1)
 			continue
 		}
 		if isResp {
@@ -603,7 +603,7 @@ func (on *RuleOn) MarshalText() ([]byte, error) {
 	return []byte(on.String()), nil
 }
 
-func parseOn(line string) (Checker, bool, gperr.Error) {
+func parseOn(line string) (Checker, bool, error) {
 	ors := splitPipe(line)
 
 	if len(ors) > 1 {
@@ -645,7 +645,7 @@ func parseOn(line string) (Checker, bool, gperr.Error) {
 
 	validArgs, err := checker.validate(args)
 	if err != nil {
-		return nil, false, err.With(checker.help.Error())
+		return nil, false, gperr.Wrap(err).With(checker.help.Error())
 	}
 
 	checkFunc := checker.builder(validArgs)

internal/route/rules/parser.go

@@ -31,7 +31,7 @@ var quoteChars = [256]bool{
 //	error 403 "Forbidden 'foo' 'bar'"
 //	error 403 Forbidden\ \"foo\"\ \"bar\".
 //	error 403 "Message: ${CLOUDFLARE_API_KEY}"
-func parse(v string) (subject string, args []string, err gperr.Error) {
+func parse(v string) (subject string, args []string, err error) {
 	buf := bytes.NewBuffer(make([]byte, 0, len(v)))
 
 	escaped := false

internal/route/rules/presets/embed.go

@@ -8,7 +8,6 @@ import (
 	"github.com/rs/zerolog/log"
 	"github.com/yusing/godoxy/internal/route/rules"
 	"github.com/yusing/godoxy/internal/serialization"
-	gperr "github.com/yusing/goutils/errs"
 )
 
 //go:embed *.yml
@@ -35,12 +34,12 @@ func initPresets() {
 		var rules rules.Rules
 		content, err := fs.ReadFile(file.Name())
 		if err != nil {
-			gperr.LogError("failed to read rule preset", err)
+			log.Err(err).Msg("failed to read rule preset")
 			continue
 		}
 		_, err = serialization.ConvertString(string(content), reflect.ValueOf(&rules))
 		if err != nil {
-			gperr.LogError("failed to unmarshal rule preset", err)
+			log.Err(err).Msg("failed to unmarshal rule preset")
 			continue
 		}
 		rulePresets[file.Name()] = rules

internal/route/rules/rules.go

@@ -7,7 +7,6 @@ import (
 
 	"github.com/quic-go/quic-go/http3"
 	"github.com/rs/zerolog/log"
-	gperr "github.com/yusing/goutils/errs"
 	httputils "github.com/yusing/goutils/http"
 	"golang.org/x/net/http2"
 
@@ -58,7 +57,7 @@ func (rule *Rule) IsResponseRule() bool {
 	return rule.On.IsResponseChecker() || rule.Do.IsResponseHandler()
 }
 
-func (rules Rules) Validate() gperr.Error {
+func (rules Rules) Validate() error {
 	var defaultRulesFound []int
 	for i, rule := range rules {
 		if rule.Name == "default" || rule.On.raw == OnDefault {

internal/route/rules/validate.go

@@ -16,7 +16,7 @@ import (
 )
 
 type (
-	ValidateFunc      func(args []string) (any, gperr.Error)
+	ValidateFunc      func(args []string) (any, error)
 	Tuple[T1, T2 any] struct {
 		First  T1
 		Second T2
@@ -62,7 +62,7 @@ func (t *Tuple4[T1, T2, T3, T4]) String() string {
 }
 
 // validateSingleMatcher returns Matcher with the matcher validated.
-func validateSingleMatcher(args []string) (any, gperr.Error) {
+func validateSingleMatcher(args []string) (any, error) {
 	if len(args) != 1 {
 		return nil, ErrExpectOneArg
 	}
@@ -70,7 +70,7 @@ func validateSingleMatcher(args []string) (any, gperr.Error) {
 }
 
 // toKVOptionalVMatcher returns *MapValueMatcher that value is optional.
-func toKVOptionalVMatcher(args []string) (any, gperr.Error) {
+func toKVOptionalVMatcher(args []string) (any, error) {
 	switch len(args) {
 	case 1:
 		return &MapValueMatcher{args[0], nil}, nil
@@ -85,7 +85,7 @@ func toKVOptionalVMatcher(args []string) (any, gperr.Error) {
 	}
 }
 
-func toKeyValueTemplate(args []string) (any, gperr.Error) {
+func toKeyValueTemplate(args []string) (any, error) {
 	if len(args) != 2 {
 		return nil, ErrExpectTwoArgs
 	}
@@ -98,7 +98,7 @@ func toKeyValueTemplate(args []string) (any, gperr.Error) {
 }
 
 // validateURL returns types.URL with the URL validated.
-func validateURL(args []string) (any, gperr.Error) {
+func validateURL(args []string) (any, error) {
 	if len(args) != 1 {
 		return nil, ErrExpectOneArg
 	}
@@ -116,7 +116,7 @@ func validateURL(args []string) (any, gperr.Error) {
 }
 
 // validateCIDR returns types.CIDR with the CIDR validated.
-func validateCIDR(args []string) (any, gperr.Error) {
+func validateCIDR(args []string) (any, error) {
 	if len(args) != 1 {
 		return nil, ErrExpectOneArg
 	}
@@ -131,7 +131,7 @@ func validateCIDR(args []string) (any, gperr.Error) {
 }
 
 // validateURLPath returns string with the path validated.
-func validateURLPath(args []string) (any, gperr.Error) {
+func validateURLPath(args []string) (any, error) {
 	if len(args) != 1 {
 		return nil, ErrExpectOneArg
 	}
@@ -148,7 +148,7 @@ func validateURLPath(args []string) (any, gperr.Error) {
 	return p, nil
 }
 
-func validateURLPathMatcher(args []string) (any, gperr.Error) {
+func validateURLPathMatcher(args []string) (any, error) {
 	path, err := validateURLPath(args)
 	if err != nil {
 		return nil, err
@@ -157,7 +157,7 @@ func validateURLPathMatcher(args []string) (any, gperr.Error) {
 }
 
 // validateFSPath returns string with the path validated.
-func validateFSPath(args []string) (any, gperr.Error) {
+func validateFSPath(args []string) (any, error) {
 	if len(args) != 1 {
 		return nil, ErrExpectOneArg
 	}
@@ -169,7 +169,7 @@ func validateFSPath(args []string) (any, gperr.Error) {
 }
 
 // validateMethod returns string with the method validated.
-func validateMethod(args []string) (any, gperr.Error) {
+func validateMethod(args []string) (any, error) {
 	if len(args) != 1 {
 		return nil, ErrExpectOneArg
 	}
@@ -200,7 +200,7 @@ func validateStatusCode(status string) (int, error) {
 //   - 3xx
 //   - 4xx
 //   - 5xx
-func validateStatusRange(args []string) (any, gperr.Error) {
+func validateStatusRange(args []string) (any, error) {
 	if len(args) != 1 {
 		return nil, ErrExpectOneArg
 	}
@@ -232,7 +232,7 @@ func validateStatusRange(args []string) (any, gperr.Error) {
 }
 
 // validateUserBCryptPassword returns *HashedCrendential with the password validated.
-func validateUserBCryptPassword(args []string) (any, gperr.Error) {
+func validateUserBCryptPassword(args []string) (any, error) {
 	if len(args) != 2 {
 		return nil, ErrExpectTwoArgs
 	}
@@ -240,7 +240,7 @@ func validateUserBCryptPassword(args []string) (any, gperr.Error) {
 }
 
 // validateModField returns CommandHandler with the field validated.
-func validateModField(mod FieldModifier, args []string) (CommandHandler, gperr.Error) {
+func validateModField(mod FieldModifier, args []string) (CommandHandler, error) {
 	if len(args) == 0 {
 		return nil, ErrExpectTwoOrThreeArgs
 	}
@@ -257,7 +257,7 @@ func validateModField(mod FieldModifier, args []string) (CommandHandler, gperr.E
 	}
 	validArgs, err := setField.validate(args[1:])
 	if err != nil {
-		return nil, err.With(setField.help.Error())
+		return nil, gperr.Wrap(err).With(setField.help.Error())
 	}
 	modder := setField.builder(validArgs)
 	switch mod {
@@ -281,7 +281,7 @@ func validateModField(mod FieldModifier, args []string) (CommandHandler, gperr.E
 	return set, nil
 }
 
-func validateTemplate(tmplStr string, newline bool) (templateString, gperr.Error) {
+func validateTemplate(tmplStr string, newline bool) (templateString, error) {
 	if newline && !strings.HasSuffix(tmplStr, "\n") {
 		tmplStr += "\n"
 	}
@@ -292,22 +292,15 @@ func validateTemplate(tmplStr string, newline bool) (templateString, gperr.Error
 
 	err := ValidateVars(tmplStr)
 	if err != nil {
-		return templateString{}, gperr.Wrap(err)
+		return templateString{}, err
 	}
 	return templateString{tmplStr, true}, nil
 }
 
-func validateLevel(level string) (zerolog.Level, gperr.Error) {
+func validateLevel(level string) (zerolog.Level, error) {
 	l, err := zerolog.ParseLevel(level)
 	if err != nil {
 		return zerolog.NoLevel, ErrInvalidArguments.With(err)
 	}
 	return l, nil
 }
-
-// func validateNotifProvider(provider string) gperr.Error {
-// 	if !notif.HasProvider(provider) {
-// 		return ErrInvalidArguments.Subject(provider)
-// 	}
-// 	return nil
-// }