Refactor docs; Add 'ipng_source_tag', add udp listener for nginx-ipng-stats plugin

internal/store/store.go

@@ -21,14 +21,16 @@ const (
 	CoarseEvery    = 5      // fine ticks between coarse writes
 )
 
-// Tuple6 is the aggregation key (website, prefix, URI, status, is_tor, asn).
+// Tuple6 is the aggregation key (website, prefix, URI, status, is_tor, asn, source_tag).
+// The name is kept for source-compat with older call sites; it now carries seven fields.
 type Tuple6 struct {
-	Website string
-	Prefix  string
-	URI     string
-	Status  string
-	IsTor   bool
-	ASN     int32
+	Website   string
+	Prefix    string
+	URI       string
+	Status    string
+	IsTor     bool
+	ASN       int32
+	SourceTag string
 }
 
 // Entry is a labelled count used in snapshots and query results.
@@ -85,12 +87,13 @@ func EncodeTuple(t Tuple6) string {
 	if t.IsTor {
 		tor = "1"
 	}
-	return t.Website + "\x00" + t.Prefix + "\x00" + t.URI + "\x00" + t.Status + "\x00" + tor + "\x00" + strconv.Itoa(int(t.ASN))
+	return t.Website + "\x00" + t.Prefix + "\x00" + t.URI + "\x00" + t.Status + "\x00" + tor + "\x00" + strconv.Itoa(int(t.ASN)) + "\x00" + t.SourceTag
 }
 
 // LabelTuple decodes a NUL-separated snapshot label back into a Tuple6.
+// Labels from older snapshots (6 fields) round-trip with SourceTag=="".
 func LabelTuple(label string) Tuple6 {
-	parts := splitN(label, '\x00', 6)
+	parts := splitN(label, '\x00', 7)
 	if len(parts) < 4 {
 		return Tuple6{}
 	}
@@ -98,11 +101,14 @@ func LabelTuple(label string) Tuple6 {
 	if len(parts) >= 5 {
 		t.IsTor = parts[4] == "1"
 	}
-	if len(parts) == 6 {
+	if len(parts) >= 6 {
 		if n, err := strconv.Atoi(parts[5]); err == nil {
 			t.ASN = int32(n)
 		}
 	}
+	if len(parts) == 7 {
+		t.SourceTag = parts[6]
+	}
 	return t
 }
 
@@ -239,6 +245,9 @@ func MatchesFilter(t Tuple6, f *CompiledFilter) bool {
 	if p.AsnNumber != nil && !matchesAsnOp(t.ASN, p.GetAsnNumber(), p.AsnOp) {
 		return false
 	}
+	if p.IpngSourceTag != nil && t.SourceTag != p.GetIpngSourceTag() {
+		return false
+	}
 	return true
 }
 
@@ -299,6 +308,8 @@ func DimensionLabel(t Tuple6, g pb.GroupBy) string {
 		return t.Status
 	case pb.GroupBy_ASN_NUMBER:
 		return strconv.Itoa(int(t.ASN))
+	case pb.GroupBy_SOURCE_TAG:
+		return t.SourceTag
 	default:
 		return t.Website
 	}

internal/store/store_test.go

@@ -335,3 +335,45 @@ func TestDimensionLabelASN(t *testing.T) {
 		t.Errorf("DimensionLabel ASN: got %q, want %q", got, "12345")
 	}
 }
+
+// --- SourceTag label encoding, filtering, and DimensionLabel ---
+
+func TestEncodeLabelTupleRoundtripWithSourceTag(t *testing.T) {
+	for _, tag := range []string{"", "direct", "cdn", "tag with spaces"} {
+		orig := Tuple6{Website: "a.com", Prefix: "1.2.3.0/24", URI: "/x", Status: "200", SourceTag: tag}
+		got := LabelTuple(EncodeTuple(orig))
+		if got != orig {
+			t.Errorf("roundtrip mismatch for tag=%q: got %+v, want %+v", tag, got, orig)
+		}
+	}
+}
+
+func TestLabelTupleBackwardCompatNoSourceTag(t *testing.T) {
+	// 6-field label (pre-source_tag snapshot) decodes with SourceTag="".
+	label := "a.com\x001.2.3.0/24\x00/x\x00200\x000\x0012345"
+	got := LabelTuple(label)
+	if got.SourceTag != "" {
+		t.Errorf("expected empty SourceTag for 6-field label, got %q", got.SourceTag)
+	}
+	if got.ASN != 12345 {
+		t.Errorf("expected ASN=12345, got %d", got.ASN)
+	}
+}
+
+func TestMatchesFilterSourceTag(t *testing.T) {
+	tag := "cdn"
+	cf := CompileFilter(&pb.Filter{IpngSourceTag: &tag})
+	if !MatchesFilter(Tuple6{SourceTag: "cdn"}, cf) {
+		t.Fatal("should match equal source_tag")
+	}
+	if MatchesFilter(Tuple6{SourceTag: "direct"}, cf) {
+		t.Fatal("should not match different source_tag")
+	}
+}
+
+func TestDimensionLabelSourceTag(t *testing.T) {
+	got := DimensionLabel(Tuple6{SourceTag: "cdn"}, pb.GroupBy_SOURCE_TAG)
+	if got != "cdn" {
+		t.Errorf("DimensionLabel SOURCE_TAG: got %q, want %q", got, "cdn")
+	}
+}