feat(model): нейтральная модель Record с нормализацией и Equal

Makefile

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+.PHONY: test
+test:
+	go test ./...
+
+.PHONY: build
+build:
+	go build ./...

go.mod

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+module github.com/vasyakrg/dns-autoresolver
+
+go 1.26.4

internal/model/record.go

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+package model
+
+import (
+	"sort"
+	"strings"
+)
+
+type RecordType string
+
+const (
+	A     RecordType = "A"
+	AAAA  RecordType = "AAAA"
+	CNAME RecordType = "CNAME"
+	MX    RecordType = "MX"
+	TXT   RecordType = "TXT"
+	SRV   RecordType = "SRV"
+	NS    RecordType = "NS"
+	SOA   RecordType = "SOA"
+)
+
+// Managed reports whether the type participates in diff+apply.
+// NS and SOA are read-only.
+func (t RecordType) Managed() bool {
+	switch t {
+	case A, AAAA, CNAME, MX, TXT, SRV:
+		return true
+	default:
+		return false
+	}
+}
+
+// Record is the provider-neutral representation of a DNS RRset.
+// For MX the value is "<priority> <target>"; for SRV it is
+// "<priority> <weight> <port> <target>". Values is an unordered set.
+type Record struct {
+	Type   RecordType
+	Name   string
+	TTL    int
+	Values []string
+}
+
+// Key uniquely identifies an RRset within a zone.
+func (r Record) Key() string {
+	return string(r.Type) + " " + normalizeName(r.Name)
+}
+
+func normalizeName(name string) string {
+	n := strings.ToLower(strings.TrimSpace(name))
+	if n != "" && !strings.HasSuffix(n, ".") {
+		n += "."
+	}
+	return n
+}
+
+// normalizeValue canonicalizes a single RR value for comparison.
+func normalizeValue(t RecordType, content string) string {
+	c := strings.Join(strings.Fields(content), " ") // collapse whitespace
+	switch t {
+	case TXT:
+		return c // case-sensitive — keep as is
+	case MX:
+		parts := strings.SplitN(c, " ", 2)
+		if len(parts) == 2 {
+			return parts[0] + " " + normalizeName(parts[1])
+		}
+		return c
+	case SRV:
+		f := strings.Fields(c)
+		if len(f) == 4 {
+			return f[0] + " " + f[1] + " " + f[2] + " " + normalizeName(f[3])
+		}
+		return c
+	case CNAME, NS:
+		return normalizeName(c)
+	default: // A, AAAA, SOA
+		return strings.ToLower(c)
+	}
+}
+
+// NormalizedValues returns sorted, normalized values.
+func (r Record) NormalizedValues() []string {
+	out := make([]string, len(r.Values))
+	for i, v := range r.Values {
+		out[i] = normalizeValue(r.Type, v)
+	}
+	sort.Strings(out)
+	return out
+}
+
+// Equal reports whether two records have the same TTL and value set.
+func (r Record) Equal(o Record) bool {
+	if r.TTL != o.TTL {
+		return false
+	}
+	a, b := r.NormalizedValues(), o.NormalizedValues()
+	if len(a) != len(b) {
+		return false
+	}
+	for i := range a {
+		if a[i] != b[i] {
+			return false
+		}
+	}
+	return true
+}

internal/model/record_test.go

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+package model
+
+import "testing"
+
+func TestManaged(t *testing.T) {
+	managed := []RecordType{A, AAAA, CNAME, MX, TXT, SRV}
+	for _, rt := range managed {
+		if !rt.Managed() {
+			t.Errorf("%s should be managed", rt)
+		}
+	}
+	for _, rt := range []RecordType{NS, SOA} {
+		if rt.Managed() {
+			t.Errorf("%s should be read-only", rt)
+		}
+	}
+}
+
+func TestKeyNormalizesName(t *testing.T) {
+	r1 := Record{Type: A, Name: "www.Example.com"}
+	r2 := Record{Type: A, Name: "www.example.com."}
+	if r1.Key() != r2.Key() {
+		t.Fatalf("keys differ: %q vs %q", r1.Key(), r2.Key())
+	}
+	if r1.Key() != "A www.example.com." {
+		t.Fatalf("unexpected key %q", r1.Key())
+	}
+}
+
+func TestEqualMXPriorityAndOrder(t *testing.T) {
+	a := Record{Type: MX, Name: "example.com.", TTL: 3600, Values: []string{"10 mx1.example.com.", "20 mx2.Example.com."}}
+	b := Record{Type: MX, Name: "example.com.", TTL: 3600, Values: []string{"20 mx2.example.com.", "10 mx1.example.com."}}
+	if !a.Equal(b) {
+		t.Fatal("MX records equal regardless of order and target case")
+	}
+	c := Record{Type: MX, Name: "example.com.", TTL: 3600, Values: []string{"30 mx1.example.com."}}
+	if a.Equal(c) {
+		t.Fatal("different priority must not be equal")
+	}
+}
+
+func TestEqualTXTCaseSensitive(t *testing.T) {
+	a := Record{Type: TXT, Name: "example.com.", TTL: 60, Values: []string{"v=DKIM1; p=AbC"}}
+	b := Record{Type: TXT, Name: "example.com.", TTL: 60, Values: []string{"v=DKIM1; p=abc"}}
+	if a.Equal(b) {
+		t.Fatal("TXT is case-sensitive")
+	}
+}
+
+func TestEqualTTLMatters(t *testing.T) {
+	a := Record{Type: A, Name: "example.com.", TTL: 300, Values: []string{"1.2.3.4"}}
+	b := Record{Type: A, Name: "example.com.", TTL: 600, Values: []string{"1.2.3.4"}}
+	if a.Equal(b) {
+		t.Fatal("different TTL must not be equal")
+	}
+}