Refactor: Replace magic numbers with named constants and enums for clarity and maintainability

libp2p/relay/circuit_v2/config.py

@@ -18,6 +18,14 @@
     RelayLimits,
 )
 
+# === Constants for relay configuration ===
+DEFAULT_MIN_RELAYS = 3
+DEFAULT_MAX_RELAYS = 20
+DEFAULT_DISCOVERY_INTERVAL = 300  # seconds
+DEFAULT_RESERVATION_TTL = 3600  # seconds
+DEFAULT_MAX_CIRCUIT_DURATION = 3600  # seconds
+DEFAULT_MAX_CIRCUIT_BYTES = 1024 * 1024 * 1024  # 1GB
+
 
 @dataclass
 class RelayConfig:
@@ -33,14 +41,14 @@ class RelayConfig:
 
     # Discovery configuration
     bootstrap_relays: list[PeerInfo] = field(default_factory=list)
-    min_relays: int = 3
-    max_relays: int = 20
-    discovery_interval: int = 300  # seconds
+    min_relays: int = DEFAULT_MIN_RELAYS
+    max_relays: int = DEFAULT_MAX_RELAYS
+    discovery_interval: int = DEFAULT_DISCOVERY_INTERVAL  # seconds
 
     # Connection configuration
-    reservation_ttl: int = 3600  # seconds
-    max_circuit_duration: int = 3600  # seconds
-    max_circuit_bytes: int = 1024 * 1024 * 1024  # 1GB
+    reservation_ttl: int = DEFAULT_RESERVATION_TTL  # seconds
+    max_circuit_duration: int = DEFAULT_MAX_CIRCUIT_DURATION  # seconds
+    max_circuit_bytes: int = DEFAULT_MAX_CIRCUIT_BYTES  # 1GB
 
     def __post_init__(self) -> None:
         """Initialize default values."""

libp2p/relay/circuit_v2/discovery.py

@@ -43,10 +43,11 @@
 
 logger = logging.getLogger("libp2p.relay.circuit_v2.discovery")
 
-# Constants
+# === Constants for relay discovery ===
 MAX_RELAYS_TO_TRACK = 10
 DEFAULT_DISCOVERY_INTERVAL = 60  # seconds
 STREAM_TIMEOUT = 10  # seconds
+PEER_PROTOCOL_TIMEOUT = 5  # seconds
 
 
 # Extended interfaces for type checking
@@ -166,19 +167,19 @@ async def discover_relays(self) -> None:
                     continue
 
                 # Check if peer supports the relay protocol
-                with trio.move_on_after(5):  # Don't wait too long for protocol info
+                with trio.move_on_after(PEER_PROTOCOL_TIMEOUT):  # Don't wait too long for protocol info
                     if await self._supports_relay_protocol(peer_id):
                         await self._add_relay(peer_id)
 
             # Limit number of relays we track
-            if len(self._discovered_relays) > self.max_relays:
+            if len(self._discovered_relays) > MAX_RELAYS_TO_TRACK:
                 # Sort by last seen time and keep only the most recent ones
                 sorted_relays = sorted(
                     self._discovered_relays.items(),
                     key=lambda x: x[1].last_seen,
                     reverse=True,
                 )
-                to_remove = sorted_relays[self.max_relays :]
+                to_remove = sorted_relays[MAX_RELAYS_TO_TRACK :]
                 for peer_id, _ in to_remove:
                     del self._discovered_relays[peer_id]
 
@@ -298,7 +299,7 @@ async def _check_via_mux(self, peer_id: ID) -> bool | None:
 
             for protocol in available_protocols:
                 try:
-                    with trio.fail_after(2):  # Quick check
+                    with trio.fail_after(PEER_PROTOCOL_TIMEOUT):  # Quick check
                         # Ensure we have a proper protocol object
                         # Use string representation since we can't use isinstance
                         is_tprotocol = str(type(protocol)) == str(type(TProtocol))
@@ -463,7 +464,7 @@ async def _cleanup_expired(self) -> None:
 
         for peer_id, relay_info in self._discovered_relays.items():
             # Check if relay hasn't been seen in a while (3x discovery interval)
-            if now - relay_info.last_seen > self.discovery_interval * 3:
+            if now - relay_info.last_seen > DEFAULT_DISCOVERY_INTERVAL * 3:
                 to_remove.append(peer_id)
                 continue
 

libp2p/relay/circuit_v2/resources.py

@@ -19,6 +19,10 @@
 # Import the protobuf definitions
 from .pb.circuit_pb2 import Reservation as PbReservation
 
+# === Constants for resource management ===
+RANDOM_BYTES_LENGTH = 16  # 128 bits of randomness
+TIMESTAMP_MULTIPLIER = 1000000  # To convert seconds to microseconds
+
 
 @dataclass
 class RelayLimits:
@@ -68,8 +72,8 @@ def _generate_voucher(self) -> bytes:
         # - Peer ID to bind it to the specific peer
         # - Timestamp for uniqueness
         # - Hash everything for a fixed size output
-        random_bytes = os.urandom(16)  # 128 bits of randomness
-        timestamp = str(int(self.created_at * 1000000)).encode()
+        random_bytes = os.urandom(RANDOM_BYTES_LENGTH)  # 128 bits of randomness
+        timestamp = str(int(self.created_at * TIMESTAMP_MULTIPLIER)).encode()
         peer_bytes = self.peer_id.to_bytes()
 
         # Combine all elements and hash them