Stop decoding unused Community and Raw fields of RIS messages (closes #9)

Community and Raw are decoded from every live message and read by no
handler; Raw is the hex of the whole BGP message. Each parsed message
sits in up to four handler queues, so retaining them is a large share of
queue memory. Tagging both json:"-" keeps them out of the decoded
message while the fields handlers use still decode. A decode test over
docs/message-examples.json confirms both stay empty and the used fields
(Path, Announcements) still populate.

Model: opus-4-8

internal/ristypes/ris.go

@@ -63,24 +63,28 @@ type RISLiveMessage struct {
 // the actual BGP update data including AS path, communities, announcements,
 // and withdrawals.
 type RISMessage struct {
-	Type            string            `json:"type"`
+	Type            string    `json:"type"`
-	Timestamp       float64           `json:"timestamp"`
+	Timestamp       float64   `json:"timestamp"`
-	ParsedTimestamp time.Time         `json:"-"` // Parsed from Timestamp field
+	ParsedTimestamp time.Time `json:"-"` // Parsed from Timestamp field
-	Peer            string            `json:"peer"`
+	Peer            string    `json:"peer"`
-	PeerASN         string            `json:"peer_asn"`
+	PeerASN         string    `json:"peer_asn"`
-	ID              string            `json:"id"`
+	ID              string    `json:"id"`
-	Host            string            `json:"host"`
+	Host            string    `json:"host"`
-	RRC             string            `json:"rrc,omitempty"`
+	RRC             string    `json:"rrc,omitempty"`
-	MrtTime         float64           `json:"mrt_time,omitempty"`
+	MrtTime         float64   `json:"mrt_time,omitempty"`
-	SocketTime      float64           `json:"socket_time,omitempty"`
+	SocketTime      float64   `json:"socket_time,omitempty"`
-	Path            ASPath            `json:"path,omitempty"`
+	Path            ASPath    `json:"path,omitempty"`
-	Community       [][]int           `json:"community,omitempty"`
+	// Community and Raw are present in the feed but read by no handler.
-	Origin          string            `json:"origin,omitempty"`
+	// They are the largest fields on a message that lives in up to four
-	MED             *int              `json:"med,omitempty"`
+	// handler queues, so json:"-" keeps them out of the decoded message
-	LocalPref       *int              `json:"local_pref,omitempty"`
+	// to save queue memory. Do not decode them without a consumer.
-	Announcements   []RISAnnouncement `json:"announcements,omitempty"`
+	Community     [][]int           `json:"-"`
-	Withdrawals     []string          `json:"withdrawals,omitempty"`
+	Origin        string            `json:"origin,omitempty"`
-	Raw             string            `json:"raw,omitempty"`
+	MED           *int              `json:"med,omitempty"`
+	LocalPref     *int              `json:"local_pref,omitempty"`
+	Announcements []RISAnnouncement `json:"announcements,omitempty"`
+	Withdrawals   []string          `json:"withdrawals,omitempty"`
+	Raw           string            `json:"-"`
 }
 
 // RISAnnouncement represents a BGP route announcement within a RIS message.

internal/ristypes/ris_test.go

@@ -0,0 +1,67 @@
+package ristypes
+
+import (
+	"bufio"
+	"encoding/json"
+	"os"
+	"testing"
+)
+
+// messageExamplesPath is the captured RIS Live feed used as decode fixtures,
+// one JSON message per line.
+const messageExamplesPath = "../../docs/message-examples.json"
+
+// TestDecodeDropsCommunityAndRaw decodes every captured message the way the
+// streamer does and checks that the fields no handler reads (Community, Raw)
+// stay empty while the fields handlers use (Path, Announcements) still decode.
+func TestDecodeDropsCommunityAndRaw(t *testing.T) {
+	f, err := os.Open(messageExamplesPath)
+	if err != nil {
+		t.Fatalf("open fixtures: %v", err)
+	}
+	defer f.Close()
+
+	var messages, withPath, withAnnouncements int
+
+	scanner := bufio.NewScanner(f)
+	scanner.Buffer(make([]byte, 0, 64*1024), 1024*1024)
+	for scanner.Scan() {
+		line := scanner.Bytes()
+		if len(line) == 0 {
+			continue
+		}
+
+		var wrapper RISLiveMessage
+		if err := json.Unmarshal(line, &wrapper); err != nil {
+			t.Fatalf("unmarshal message %d: %v", messages+1, err)
+		}
+		messages++
+
+		msg := wrapper.Data
+		if msg.Community != nil {
+			t.Errorf("message %d: Community decoded, want empty: %v", messages, msg.Community)
+		}
+		if msg.Raw != "" {
+			t.Errorf("message %d: Raw decoded, want empty", messages)
+		}
+
+		if len(msg.Path) > 0 {
+			withPath++
+		}
+		if len(msg.Announcements) > 0 {
+			withAnnouncements++
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		t.Fatalf("scan fixtures: %v", err)
+	}
+
+	if messages == 0 {
+		t.Fatal("no messages decoded from fixtures")
+	}
+	// The fixtures include announcement messages; a used field must still decode,
+	// otherwise an empty Community/Raw would prove nothing.
+	if withPath == 0 || withAnnouncements == 0 {
+		t.Fatalf("used fields did not decode: withPath=%d withAnnouncements=%d", withPath, withAnnouncements)
+	}
+}