Initial commit: RouteWatch BGP stream monitor

- Connects to RIPE RIS Live stream to receive real-time BGP updates
- Stores BGP data in SQLite database:
  - ASNs with first/last seen timestamps
  - Prefixes with IPv4/IPv6 classification
  - BGP announcements and withdrawals
  - AS-to-AS peering relationships from AS paths
  - Live routing table tracking active routes
- HTTP server with statistics endpoints
- Metrics tracking with go-metrics
- Custom JSON unmarshaling to handle nested AS sets in paths
- Dependency injection with uber/fx
- Pure Go implementation (no CGO)
- Includes streamdumper utility for debugging raw messages

internal/routewatch/handler.go

@@ -0,0 +1,45 @@
+package routewatch
+
+import (
+	"git.eeqj.de/sneak/routewatch/internal/ristypes"
+	"log/slog"
+)
+
+// SimpleHandler is a basic implementation of streamer.MessageHandler
+type SimpleHandler struct {
+	logger       *slog.Logger
+	messageTypes []string
+	callback     func(*ristypes.RISMessage)
+}
+
+// NewSimpleHandler creates a handler that accepts specific message types
+func NewSimpleHandler(logger *slog.Logger, messageTypes []string, callback func(*ristypes.RISMessage)) *SimpleHandler {
+	return &SimpleHandler{
+		logger:       logger,
+		messageTypes: messageTypes,
+		callback:     callback,
+	}
+}
+
+// WantsMessage returns true if this handler wants to process messages of the given type
+func (h *SimpleHandler) WantsMessage(messageType string) bool {
+	// If no specific types are set, accept all messages
+	if len(h.messageTypes) == 0 {
+		return true
+	}
+
+	for _, t := range h.messageTypes {
+		if t == messageType {
+			return true
+		}
+	}
+
+	return false
+}
+
+// HandleMessage processes a RIS message
+func (h *SimpleHandler) HandleMessage(msg *ristypes.RISMessage) {
+	if h.callback != nil {
+		h.callback(msg)
+	}
+}