Add IP information API with background WHOIS fetcher

- Add /ip and /ip/{addr} JSON endpoints returning comprehensive IP info
- Include ASN, netblock, country code, org name, abuse contact, RIR data
- Extend ASN schema with WHOIS fields (country, org, abuse contact, etc)
- Create background WHOIS fetcher for rate-limited ASN info updates
- Store raw WHOIS responses for debugging and data preservation
- Queue on-demand WHOIS lookups when stale data is requested
- Refactor handleIPInfo to serve all IP endpoints consistently

internal/routewatch/asnfetcher.go

@@ -0,0 +1,155 @@
+// Package routewatch contains the ASN WHOIS fetcher for background updates.
+package routewatch
+
+import (
+	"context"
+	"log/slog"
+	"sync"
+	"time"
+
+	"git.eeqj.de/sneak/routewatch/internal/database"
+	"git.eeqj.de/sneak/routewatch/internal/whois"
+)
+
+// ASN fetcher configuration constants.
+const (
+	// backgroundFetchInterval is how often the background fetcher runs.
+	backgroundFetchInterval = time.Minute
+
+	// whoisStaleThreshold is how old WHOIS data can be before refresh.
+	whoisStaleThreshold = 30 * 24 * time.Hour // 30 days
+
+	// immediateQueueSize is the buffer size for immediate fetch requests.
+	immediateQueueSize = 100
+)
+
+// ASNFetcher handles background WHOIS lookups for ASNs.
+type ASNFetcher struct {
+	db             database.Store
+	whoisClient    *whois.Client
+	logger         *slog.Logger
+	immediateQueue chan int
+	stopCh         chan struct{}
+	wg             sync.WaitGroup
+}
+
+// NewASNFetcher creates a new ASN fetcher.
+func NewASNFetcher(db database.Store, logger *slog.Logger) *ASNFetcher {
+	return &ASNFetcher{
+		db:             db,
+		whoisClient:    whois.NewClient(),
+		logger:         logger.With("component", "asn_fetcher"),
+		immediateQueue: make(chan int, immediateQueueSize),
+		stopCh:         make(chan struct{}),
+	}
+}
+
+// Start begins the background ASN fetcher goroutine.
+func (f *ASNFetcher) Start() {
+	f.wg.Add(1)
+	go f.run()
+	f.logger.Info("ASN fetcher started", "interval", backgroundFetchInterval)
+}
+
+// Stop gracefully shuts down the fetcher.
+func (f *ASNFetcher) Stop() {
+	close(f.stopCh)
+	f.wg.Wait()
+	f.logger.Info("ASN fetcher stopped")
+}
+
+// QueueImmediate queues an ASN for immediate WHOIS lookup.
+// Non-blocking - if queue is full, the request is dropped.
+func (f *ASNFetcher) QueueImmediate(asn int) {
+	select {
+	case f.immediateQueue <- asn:
+		f.logger.Debug("Queued immediate WHOIS lookup", "asn", asn)
+	default:
+		f.logger.Debug("Immediate queue full, dropping request", "asn", asn)
+	}
+}
+
+// run is the main background loop.
+func (f *ASNFetcher) run() {
+	defer f.wg.Done()
+
+	ticker := time.NewTicker(backgroundFetchInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-f.stopCh:
+			return
+
+		case asn := <-f.immediateQueue:
+			// Process immediate request
+			f.fetchAndUpdate(asn)
+
+		case <-ticker.C:
+			// Background fetch of stale/missing ASN
+			f.fetchNextStale()
+		}
+	}
+}
+
+// fetchNextStale finds and fetches the next ASN needing WHOIS data.
+func (f *ASNFetcher) fetchNextStale() {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	asn, err := f.db.GetNextStaleASN(ctx, whoisStaleThreshold)
+	if err != nil {
+		if err != database.ErrNoStaleASN {
+			f.logger.Error("Failed to get stale ASN", "error", err)
+		}
+
+		return
+	}
+
+	f.fetchAndUpdate(asn)
+}
+
+// fetchAndUpdate performs a WHOIS lookup and updates the database.
+func (f *ASNFetcher) fetchAndUpdate(asn int) {
+	ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+	defer cancel()
+
+	f.logger.Info("Fetching WHOIS data", "asn", asn)
+
+	info, err := f.whoisClient.LookupASN(ctx, asn)
+	if err != nil {
+		f.logger.Error("WHOIS lookup failed", "asn", asn, "error", err)
+
+		return
+	}
+
+	// Update database with WHOIS data
+	err = f.db.UpdateASNWHOIS(ctx, &database.ASNWHOISUpdate{
+		ASN:         asn,
+		ASName:      info.ASName,
+		OrgName:     info.OrgName,
+		OrgID:       info.OrgID,
+		Address:     info.Address,
+		CountryCode: info.CountryCode,
+		AbuseEmail:  info.AbuseEmail,
+		AbusePhone:  info.AbusePhone,
+		TechEmail:   info.TechEmail,
+		TechPhone:   info.TechPhone,
+		RIR:         info.RIR,
+		RIRRegDate:  info.RegDate,
+		RIRLastMod:  info.LastMod,
+		WHOISRaw:    info.RawResponse,
+	})
+	if err != nil {
+		f.logger.Error("Failed to update ASN WHOIS data", "asn", asn, "error", err)
+
+		return
+	}
+
+	f.logger.Info("Updated ASN WHOIS data",
+		"asn", asn,
+		"org_name", info.OrgName,
+		"country", info.CountryCode,
+		"rir", info.RIR,
+	)
+}