refactor(s3api): move Lifecycle XML structs to leaf package lifecycle_xml (#9360)

* refactor(s3api): move Lifecycle XML structs to leaf package lifecycle_xml

The structs S3 PutBucketLifecycleConfiguration parses and the canonical
conversion to s3lifecycle.Rule lived in package s3api, which transitively
imports weed/server (which imports weed/shell). Any caller outside
weed/s3api — the shell, the future lifecycle worker — that wanted to
parse a bucket's lifecycle XML hit an import cycle.

Moves:
  weed/s3api/s3api_policy.go              -> lifecycle_xml/types.go
  weed/s3api/s3api_lifecycle_canonical.go -> lifecycle_xml/canonical.go
  s3api_lifecycle_canonical_test.go       -> lifecycle_xml/canonical_test.go
  s3api_policy_test.go                    -> lifecycle_xml/round_trip_test.go

Renames the public RuleStatus type (was unexported ruleStatus) and adds
small accessor methods (Set/Val/AndSet/TagSet) for fields the s3api
handler needs to read across the package boundary. Adds NewPrefix and
NewExpirationDays constructors so the GET handler can build response
rules without poking at unexported fields. Adds a Tag struct local to
the package so it has zero internal seaweed deps. Adds a one-shot
ParseCanonical(xml []byte) helper for non-server callers.

s3api_policy.go was misnamed — its content is lifecycle XML, not S3
bucket policy. The new package name reflects the actual scope.

* test(s3api/lifecycle_xml): exercise public API in tests

- canonical_test.go's parseLifecycle helper went through xml.Unmarshal
  directly; route it through the package's exported Parse so tests
  validate the public entrypoint.
- round_trip_test.go asserted internal flags (rule.Filter.tagSet,
  rule.Filter.andSet, Transition.set, NoncurrentVersionTransition.set);
  switch to TagSet(), AndSet(), Set() — exercises the public contract
  that downstream callers (s3api handler, future shell command) rely on.

weed/s3api/lifecycle_xml/canonical.go

@@ -1,9 +1,32 @@
-package s3api
+package lifecycle_xml
 
 import (
+	"bytes"
+	"encoding/xml"
+
 	"github.com/seaweedfs/seaweedfs/weed/s3api/s3lifecycle"
 )
 
+// Parse decodes a BucketLifecycleConfiguration XML body into the wire-form
+// Lifecycle struct.
+func Parse(xmlBytes []byte) (*Lifecycle, error) {
+	var lc Lifecycle
+	if err := xml.NewDecoder(bytes.NewReader(xmlBytes)).Decode(&lc); err != nil {
+		return nil, err
+	}
+	return &lc, nil
+}
+
+// ParseCanonical is the one-shot path most non-server callers want:
+// raw XML in, []*s3lifecycle.Rule out.
+func ParseCanonical(xmlBytes []byte) ([]*s3lifecycle.Rule, error) {
+	lc, err := Parse(xmlBytes)
+	if err != nil {
+		return nil, err
+	}
+	return LifecycleToCanonical(lc), nil
+}
+
 // LifecycleToCanonical flattens the XML-deserialized Lifecycle into the
 // engine's flat Rule shape. The optional <Filter> element may contain
 // <Prefix> | <Tag> | <And>, or be absent (in which case the older top-level

weed/s3api/lifecycle_xml/canonical_test.go

@@ -1,20 +1,19 @@
-package s3api
+package lifecycle_xml
 
 import (
-	"encoding/xml"
 	"reflect"
 	"testing"
 	"time"
 )
 
-// parseLifecycle is a thin helper for tests; production code reads XML via the
-// regular bucket-config decoder, this shortcut keeps the test focused on the
-// canonical conversion.
+// parseLifecycle is a thin helper for tests; production code reads XML via
+// the regular bucket-config decoder, this shortcut goes through the
+// package's public Parse so the tests exercise the exported entrypoint.
 func parseLifecycle(t *testing.T, xmlSrc string) *Lifecycle {
 	t.Helper()
-	lc := &Lifecycle{}
-	if err := xml.Unmarshal([]byte(xmlSrc), lc); err != nil {
-		t.Fatalf("unmarshal: %v", err)
+	lc, err := Parse([]byte(xmlSrc))
+	if err != nil {
+		t.Fatalf("parse: %v", err)
 	}
 	return lc
 }

weed/s3api/lifecycle_xml/round_trip_test.go

@@ -1,4 +1,4 @@
-package s3api
+package lifecycle_xml
 
 import (
 	"encoding/xml"
@@ -101,8 +101,8 @@ func TestLifecycleXMLRoundTrip_FilterWithTag(t *testing.T) {
 	}
 
 	rule := lc.Rules[0]
-	if !rule.Filter.tagSet {
-		t.Error("expected Filter.tagSet to be true")
+	if !rule.Filter.TagSet() {
+		t.Error("expected Filter.TagSet() to be true")
 	}
 	if rule.Filter.Tag.Key != "env" || rule.Filter.Tag.Value != "dev" {
 		t.Errorf("expected Tag{env:dev}, got Tag{%s:%s}", rule.Filter.Tag.Key, rule.Filter.Tag.Value)
@@ -133,8 +133,8 @@ func TestLifecycleXMLRoundTrip_FilterWithAnd(t *testing.T) {
 	}
 
 	rule := lc.Rules[0]
-	if !rule.Filter.andSet {
-		t.Error("expected Filter.andSet to be true")
+	if !rule.Filter.AndSet() {
+		t.Error("expected Filter.AndSet() to be true")
 	}
 	if rule.Filter.And.Prefix.String() != "logs/" {
 		t.Errorf("expected And.Prefix='logs/', got %q", rule.Filter.And.Prefix.String())
@@ -178,7 +178,7 @@ func TestLifecycleXMLRoundTrip_FilterWithSizeOnly(t *testing.T) {
 }
 
 func TestLifecycleXML_TransitionSetFlag(t *testing.T) {
-	// Verify that Transition.set is true after unmarshaling.
+	// Verify that Transition.Set() is true after unmarshaling.
 	input := `<LifecycleConfiguration>
   <Rule>
     <ID>transition</ID>
@@ -195,8 +195,8 @@ func TestLifecycleXML_TransitionSetFlag(t *testing.T) {
 	if err := xml.Unmarshal([]byte(input), &lc); err != nil {
 		t.Fatalf("unmarshal: %v", err)
 	}
-	if !lc.Rules[0].Transition.set {
-		t.Error("expected Transition.set=true after unmarshal")
+	if !lc.Rules[0].Transition.Set() {
+		t.Error("expected Transition.Set()=true after unmarshal")
 	}
 }
 
@@ -217,8 +217,8 @@ func TestLifecycleXML_NoncurrentVersionTransitionSetFlag(t *testing.T) {
 	if err := xml.Unmarshal([]byte(input), &lc); err != nil {
 		t.Fatalf("unmarshal: %v", err)
 	}
-	if !lc.Rules[0].NoncurrentVersionTransition.set {
-		t.Error("expected NoncurrentVersionTransition.set=true after unmarshal")
+	if !lc.Rules[0].NoncurrentVersionTransition.Set() {
+		t.Error("expected NoncurrentVersionTransition.Set()=true after unmarshal")
 	}
 }
 

weed/s3api/lifecycle_xml/types.go

@@ -1,19 +1,36 @@
-package s3api
+// Package lifecycle_xml is the XML wire-form for S3 BucketLifecycleConfiguration:
+// the structs S3 PutBucketLifecycleConfiguration accepts and
+// GetBucketLifecycleConfiguration returns. It lives outside weed/s3api so
+// callers outside that package (shell, lifecycle worker) can parse and
+// emit the same shape without pulling weed/s3api's full dependency graph
+// — weed/s3api transitively imports weed/server, which imports weed/shell.
+//
+// Conversion to the engine-friendly canonical form
+// (weed/s3api/s3lifecycle.Rule) lives next to the types here as
+// LifecycleToCanonical.
+package lifecycle_xml
 
 import (
 	"encoding/xml"
 	"time"
 )
 
-// Status represents lifecycle configuration status
-type ruleStatus string
+// RuleStatus represents lifecycle rule status.
+type RuleStatus string
 
-// Supported status types
+// Supported status types.
 const (
-	Enabled  ruleStatus = "Enabled"
-	Disabled ruleStatus = "Disabled"
+	Enabled  RuleStatus = "Enabled"
+	Disabled RuleStatus = "Disabled"
 )
 
+// Tag is the lifecycle filter tag pair. Defined locally so this package
+// has no dependency on weed/s3api.
+type Tag struct {
+	Key   string `xml:"Key"`
+	Value string `xml:"Value"`
+}
+
 // Lifecycle - Configuration for bucket lifecycle.
 type Lifecycle struct {
 	XMLName xml.Name `xml:"LifecycleConfiguration"`
@@ -24,7 +41,7 @@ type Lifecycle struct {
 type Rule struct {
 	XMLName                        xml.Name                       `xml:"Rule"`
 	ID                             string                         `xml:"ID,omitempty"`
-	Status                         ruleStatus                     `xml:"Status"`
+	Status                         RuleStatus                     `xml:"Status"`
 	Filter                         Filter                         `xml:"Filter,omitempty"`
 	Prefix                         Prefix                         `xml:"Prefix,omitempty"`
 	Expiration                     Expiration                     `xml:"Expiration,omitempty"`
@@ -63,6 +80,36 @@ func (p Prefix) String() string {
 	return p.val
 }
 
+// Set returns whether the Prefix carries a value (vs being absent).
+func (p Prefix) Set() bool { return p.set }
+
+// Val returns the prefix string. Empty when !Set.
+func (p Prefix) Val() string { return p.val }
+
+// NewPrefix builds a Prefix marked as set.
+func NewPrefix(val string) Prefix { return Prefix{val: val, set: true} }
+
+// NewExpirationDays builds an Expiration with Days set.
+func NewExpirationDays(days int) Expiration { return Expiration{Days: days, set: true} }
+
+// Set reports whether this Filter is present in the XML.
+func (f Filter) Set() bool { return f.set }
+
+// AndSet reports whether the Filter contains an <And> branch.
+func (f Filter) AndSet() bool { return f.andSet }
+
+// TagSet reports whether the Filter contains a single <Tag> branch.
+func (f Filter) TagSet() bool { return f.tagSet }
+
+// Set reports whether the Transition element was present.
+func (t Transition) Set() bool { return t.set }
+
+// Set reports whether the NoncurrentVersionTransition element was present.
+func (n NoncurrentVersionTransition) Set() bool { return n.set }
+
+// Set reports whether the Expiration element was present.
+func (e Expiration) Set() bool { return e.set }
+
 // MarshalXML encodes Prefix field into an XML form.
 func (p Prefix) MarshalXML(e *xml.Encoder, startElement xml.StartElement) error {
 	if !p.set {

weed/s3api/s3api_bucket_handlers.go

@@ -20,6 +20,7 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/s3api/s3bucket"
 
 	"github.com/seaweedfs/seaweedfs/weed/filer"
+	"github.com/seaweedfs/seaweedfs/weed/s3api/lifecycle_xml"
 	"github.com/seaweedfs/seaweedfs/weed/s3api/s3_constants"
 	stats_collect "github.com/seaweedfs/seaweedfs/weed/stats"
 	"github.com/seaweedfs/seaweedfs/weed/storage/needle"
@@ -840,7 +841,7 @@ func (s3a *S3ApiServer) GetBucketLifecycleConfigurationHandler(w http.ResponseWr
 		return
 	}
 
-	response := Lifecycle{}
+	response := lifecycle_xml.Lifecycle{}
 	// Sort locationPrefixes to ensure consistent ordering of lifecycle rules
 	var locationPrefixes []string
 	for locationPrefix := range ttls {
@@ -859,11 +860,11 @@ func (s3a *S3ApiServer) GetBucketLifecycleConfigurationHandler(w http.ResponseWr
 		if !found {
 			continue
 		}
-		response.Rules = append(response.Rules, Rule{
+		response.Rules = append(response.Rules, lifecycle_xml.Rule{
 			ID:         prefix,
-			Status:     Enabled,
-			Prefix:     Prefix{val: prefix, set: true},
-			Expiration: Expiration{Days: days, set: true},
+			Status:     lifecycle_xml.Enabled,
+			Prefix:     lifecycle_xml.NewPrefix(prefix),
+			Expiration: lifecycle_xml.NewExpirationDays(days),
 		})
 	}
 
@@ -920,7 +921,7 @@ func (s3a *S3ApiServer) PutBucketLifecycleConfigurationHandler(w http.ResponseWr
 		return
 	}
 
-	lifeCycleConfig := Lifecycle{}
+	lifeCycleConfig := lifecycle_xml.Lifecycle{}
 	if err := xmlDecoder(bytes.NewReader(lifecycleXML), &lifeCycleConfig, int64(len(lifecycleXML))); err != nil {
 		glog.Warningf("PutBucketLifecycleConfigurationHandler xml decode: %s", err)
 		s3err.WriteErrorResponse(w, r, s3err.ErrMalformedXML)
@@ -977,12 +978,12 @@ func (s3a *S3ApiServer) PutBucketLifecycleConfigurationHandler(w http.ResponseWr
 		bucketVersioning == s3_constants.VersioningSuspended
 
 	for _, rule := range lifeCycleConfig.Rules {
-		if rule.Status != Enabled {
+		if rule.Status != lifecycle_xml.Enabled {
 			continue
 		}
 		// Reject Transition rules — they require storage class migration
 		// infrastructure that does not exist yet.
-		if rule.Transition.set || rule.NoncurrentVersionTransition.set {
+		if rule.Transition.Set() || rule.NoncurrentVersionTransition.Set() {
 			s3err.WriteErrorResponse(w, r, s3err.ErrNotImplemented)
 			return
 		}
@@ -993,12 +994,12 @@ func (s3a *S3ApiServer) PutBucketLifecycleConfigurationHandler(w http.ResponseWr
 
 		var rulePrefix string
 		switch {
-		case rule.Filter.andSet:
-			rulePrefix = rule.Filter.And.Prefix.val
-		case rule.Filter.Prefix.set:
-			rulePrefix = rule.Filter.Prefix.val
-		case rule.Prefix.set:
-			rulePrefix = rule.Prefix.val
+		case rule.Filter.AndSet():
+			rulePrefix = rule.Filter.And.Prefix.Val()
+		case rule.Filter.Prefix.Set():
+			rulePrefix = rule.Filter.Prefix.Val()
+		case rule.Prefix.Set():
+			rulePrefix = rule.Prefix.Val()
 		}
 
 		// Only create filer.conf TTL entries for simple Expiration.Days rules
@@ -1009,9 +1010,9 @@ func (s3a *S3ApiServer) PutBucketLifecycleConfigurationHandler(w http.ResponseWr
 		if rule.Expiration.Days == 0 {
 			continue
 		}
-		hasTagOrSizeFilter := rule.Filter.tagSet ||
+		hasTagOrSizeFilter := rule.Filter.TagSet() ||
 			rule.Filter.ObjectSizeGreaterThan > 0 || rule.Filter.ObjectSizeLessThan > 0 ||
-			(rule.Filter.andSet && (len(rule.Filter.And.Tags) > 0 ||
+			(rule.Filter.AndSet() && (len(rule.Filter.And.Tags) > 0 ||
 				rule.Filter.And.ObjectSizeGreaterThan > 0 || rule.Filter.And.ObjectSizeLessThan > 0))
 		if hasTagOrSizeFilter {
 			continue // evaluated by lifecycle worker at scan time