refactor: move accesslog to logging/accesslog

internal/logging/accesslog/fields.go

@@ -0,0 +1,204 @@
+package accesslog
+
+import (
+	"iter"
+	"net/http"
+	"net/url"
+
+	"github.com/rs/zerolog"
+)
+
+type (
+	FieldConfig struct {
+		Default FieldMode            `json:"default" validate:"oneof=keep drop redact"`
+		Config  map[string]FieldMode `json:"config" validate:"dive,oneof=keep drop redact"`
+	}
+	FieldMode string
+)
+
+const (
+	FieldModeKeep   FieldMode = "keep"
+	FieldModeDrop   FieldMode = "drop"
+	FieldModeRedact FieldMode = "redact"
+
+	RedactedValue = "REDACTED"
+)
+
+type mapStringStringIter interface {
+	Iter(yield func(k string, v []string) bool)
+	MarshalZerologObject(e *zerolog.Event)
+}
+
+type mapStringStringSlice struct {
+	m map[string][]string
+}
+
+func (m mapStringStringSlice) Iter(yield func(k string, v []string) bool) {
+	for k, v := range m.m {
+		if !yield(k, v) {
+			return
+		}
+	}
+}
+
+func (m mapStringStringSlice) MarshalZerologObject(e *zerolog.Event) {
+	for k, v := range m.m {
+		e.Strs(k, v)
+	}
+}
+
+type mapStringStringRedacted struct {
+	m map[string][]string
+}
+
+func (m mapStringStringRedacted) Iter(yield func(k string, v []string) bool) {
+	for k := range m.m {
+		if !yield(k, []string{RedactedValue}) {
+			return
+		}
+	}
+}
+
+func (m mapStringStringRedacted) MarshalZerologObject(e *zerolog.Event) {
+	for k, v := range m.Iter {
+		e.Strs(k, v)
+	}
+}
+
+type mapStringStringSliceWithConfig struct {
+	m   map[string][]string
+	cfg *FieldConfig
+}
+
+func (m mapStringStringSliceWithConfig) Iter(yield func(k string, v []string) bool) {
+	var mode FieldMode
+	var ok bool
+	for k, v := range m.m {
+		if mode, ok = m.cfg.Config[k]; !ok {
+			mode = m.cfg.Default
+		}
+		switch mode {
+		case FieldModeKeep:
+			if !yield(k, v) {
+				return
+			}
+		case FieldModeRedact:
+			if !yield(k, []string{RedactedValue}) {
+				return
+			}
+		}
+	}
+}
+
+func (m mapStringStringSliceWithConfig) MarshalZerologObject(e *zerolog.Event) {
+	for k, v := range m.Iter {
+		e.Strs(k, v)
+	}
+}
+
+type mapStringStringDrop struct{}
+
+func (m mapStringStringDrop) Iter(yield func(k string, v []string) bool) {}
+func (m mapStringStringDrop) MarshalZerologObject(e *zerolog.Event)      {}
+
+var mapStringStringDropIter mapStringStringIter = mapStringStringDrop{}
+
+func mapIter[Map http.Header | url.Values](cfg *FieldConfig, m Map) mapStringStringIter {
+	if len(cfg.Config) == 0 {
+		switch cfg.Default {
+		case FieldModeKeep:
+			return mapStringStringSlice{m: m}
+		case FieldModeDrop:
+			return mapStringStringDropIter
+		case FieldModeRedact:
+			return mapStringStringRedacted{m: m}
+		}
+	}
+	return mapStringStringSliceWithConfig{m: m, cfg: cfg}
+}
+
+type slice[V any] struct {
+	s      []V
+	getKey func(V) string
+	getVal func(V) string
+	cfg    *FieldConfig
+}
+
+type sliceIter interface {
+	Iter(yield func(k string, v string) bool)
+	MarshalZerologObject(e *zerolog.Event)
+}
+
+func (s *slice[V]) Iter(yield func(k string, v string) bool) {
+	for _, v := range s.s {
+		k := s.getKey(v)
+		var mode FieldMode
+		var ok bool
+		if mode, ok = s.cfg.Config[k]; !ok {
+			mode = s.cfg.Default
+		}
+		switch mode {
+		case FieldModeKeep:
+			if !yield(k, s.getVal(v)) {
+				return
+			}
+		case FieldModeRedact:
+			if !yield(k, RedactedValue) {
+				return
+			}
+		}
+	}
+}
+
+type sliceDrop struct{}
+
+func (s sliceDrop) Iter(yield func(k string, v string) bool) {}
+func (s sliceDrop) MarshalZerologObject(e *zerolog.Event)    {}
+
+var sliceDropIter sliceIter = sliceDrop{}
+
+func (s *slice[V]) MarshalZerologObject(e *zerolog.Event) {
+	for k, v := range s.Iter {
+		e.Str(k, v)
+	}
+}
+
+func iterSlice[V any](cfg *FieldConfig, s []V, getKey func(V) string, getVal func(V) string) sliceIter {
+	if len(s) == 0 ||
+		len(cfg.Config) == 0 && cfg.Default == FieldModeDrop {
+		return sliceDropIter
+	}
+	return &slice[V]{s: s, getKey: getKey, getVal: getVal, cfg: cfg}
+}
+
+func (cfg *FieldConfig) IterHeaders(headers http.Header) iter.Seq2[string, []string] {
+	return mapIter(cfg, headers).Iter
+}
+
+func (cfg *FieldConfig) ZerologHeaders(headers http.Header) zerolog.LogObjectMarshaler {
+	return mapIter(cfg, headers)
+}
+
+func (cfg *FieldConfig) IterQuery(q url.Values) iter.Seq2[string, []string] {
+	return mapIter(cfg, q).Iter
+}
+
+func (cfg *FieldConfig) ZerologQuery(q url.Values) zerolog.LogObjectMarshaler {
+	return mapIter(cfg, q)
+}
+
+func cookieGetKey(c *http.Cookie) string {
+	return c.Name
+}
+
+func cookieGetValue(c *http.Cookie) string {
+	return c.Value
+}
+
+func (cfg *FieldConfig) IterCookies(cookies []*http.Cookie) iter.Seq2[string, string] {
+	return iterSlice(cfg, cookies, cookieGetKey, cookieGetValue).Iter
+}
+
+func (cfg *FieldConfig) ZerologCookies(cookies []*http.Cookie) zerolog.LogObjectMarshaler {
+	return iterSlice(cfg, cookies, cookieGetKey, cookieGetValue)
+}