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
 	}