feat: add env var to control active probing

cached_addr_book.go

@@ -88,6 +88,7 @@ type peerState struct {
 type cachedAddrBook struct {
 	addrBook             peerstore.AddrBook             // memory address book
 	peerCache            *lru.Cache[peer.ID, peerState] // LRU cache with additional metadata about peer
+	probingEnabled       bool
 	isProbing            atomic.Bool
 	allowPrivateIPs      bool // for testing
 	recentlyConnectedTTL time.Duration
@@ -109,6 +110,13 @@ func WithRecentlyConnectedTTL(ttl time.Duration) AddrBookOption {
 	}
 }
 
+func WithActiveProbing(enabled bool) AddrBookOption {
+	return func(cab *cachedAddrBook) error {
+		cab.probingEnabled = enabled
+		return nil
+	}
+}
+
 func newCachedAddrBook(opts ...AddrBookOption) (*cachedAddrBook, error) {
 	peerCache, err := lru.New[peer.ID, peerState](PeerCacheSize)
 	if err != nil {
@@ -127,7 +135,8 @@ func newCachedAddrBook(opts ...AddrBookOption) (*cachedAddrBook, error) {
 			return nil, err
 		}
 	}
-	logger.Infof("cachedAddrBook: Using TTL of %s for recently connected peers", cab.recentlyConnectedTTL)
+	logger.Infof("Using TTL of %s for recently connected peers", cab.recentlyConnectedTTL)
+	logger.Infof("Probing enabled: %t", cab.probingEnabled)
 	return cab, nil
 }
 
@@ -191,6 +200,10 @@ func (cab *cachedAddrBook) background(ctx context.Context, host host.Host) {
 				}
 			}
 		case <-probeTicker.C:
+			if !cab.probingEnabled {
+				logger.Debug("Probing disabled, skipping")
+				continue
+			}
 			if cab.isProbing.Load() {
 				logger.Debug("Skipping peer probe, still running")
 				continue

docs/environment-variables.md

@@ -49,6 +49,12 @@ The TTL for recently connected peers' multiaddrs in the cached address book.
 
 Default: `48h`
 
+### `SOMEGUY_CACHED_ADDR_BOOK_ACTIVE_PROBING`
+
+Whether or not the Cached Address Book should actively probe peers in cache to keep their multiaddrs up to date.
+
+Default: `true`
+
 ### `SOMEGUY_PROVIDER_ENDPOINTS`
 
 Comma-separated list of other Delegated Routing V1 endpoints to proxy provider requests to.

main.go

@@ -44,6 +44,12 @@ func main() {
 						EnvVars: []string{"SOMEGUY_CACHED_ADDR_BOOK"},
 						Usage:   "use a cached address book to improve provider lookup responses",
 					},
+					&cli.BoolFlag{
+						Name:    "cached-addr-book-active-probing",
+						Value:   true,
+						EnvVars: []string{"SOMEGUY_CACHED_ADDR_BOOK_ACTIVE_PROBING"},
+						Usage:   "actively probe peers in cache to keep their multiaddrs up to date",
+					},
 					&cli.DurationFlag{
 						Name:        "cached-addr-book-recent-ttl",
 						DefaultText: DefaultRecentlyConnectedAddrTTL.String(),
@@ -128,10 +134,11 @@ func main() {
 				},
 				Action: func(ctx *cli.Context) error {
 					cfg := &config{
-						listenAddress:           ctx.String("listen-address"),
-						acceleratedDHTClient:    ctx.Bool("accelerated-dht"),
-						cachedAddrBook:          ctx.Bool("cached-addr-book"),
-						cachedAddrBookRecentTTL: ctx.Duration("cached-addr-book-recent-ttl"),
+						listenAddress:               ctx.String("listen-address"),
+						acceleratedDHTClient:        ctx.Bool("accelerated-dht"),
+						cachedAddrBook:              ctx.Bool("cached-addr-book"),
+						cachedAddrBookActiveProbing: ctx.Bool("cached-addr-book-active-probing"),
+						cachedAddrBookRecentTTL:     ctx.Duration("cached-addr-book-recent-ttl"),
 
 						contentEndpoints: ctx.StringSlice("provider-endpoints"),
 						peerEndpoints:    ctx.StringSlice("peer-endpoints"),

server.go

@@ -40,10 +40,11 @@ func withRequestLogger(next http.Handler) http.Handler {
 }
 
 type config struct {
-	listenAddress           string
-	acceleratedDHTClient    bool
-	cachedAddrBook          bool
-	cachedAddrBookRecentTTL time.Duration
+	listenAddress               string
+	acceleratedDHTClient        bool
+	cachedAddrBook              bool
+	cachedAddrBookActiveProbing bool
+	cachedAddrBookRecentTTL     time.Duration
 
 	contentEndpoints []string
 	peerEndpoints    []string
@@ -85,13 +86,15 @@ func start(ctx context.Context, cfg *config) error {
 	var cachedAddrBook *cachedAddrBook
 
 	if cfg.cachedAddrBook {
-		fmt.Println("Using cached address book to speed up provider discovery")
+		fmt.Printf("Using cached address book to speed up provider discovery (active probing enabled: %t)\n", cfg.cachedAddrBookActiveProbing)
 		opts := []AddrBookOption{}
 
 		if cfg.cachedAddrBookRecentTTL > 0 {
 			opts = append(opts, WithRecentlyConnectedTTL(cfg.cachedAddrBookRecentTTL))
 		}
 
+		opts = append(opts, WithActiveProbing(cfg.cachedAddrBookActiveProbing))
+
 		cachedAddrBook, err = newCachedAddrBook(opts...)
 		if err != nil {
 			return err