Merge branch 'main' into main

Author: seetadev

docs/examples.mDNS.rst

@@ -0,0 +1,64 @@
+mDNS Peer Discovery Example
+===========================
+
+This example demonstrates how to use mDNS (Multicast DNS) for peer discovery in py-libp2p.
+
+Prerequisites
+-------------
+
+First, ensure you have py-libp2p installed and your environment is activated:
+
+.. code-block:: console
+
+    $ python -m pip install libp2p
+
+Running the Example
+-------------------
+
+The mDNS demo script allows you to discover peers on your local network using mDNS. To start a peer, run:
+
+.. code-block:: console
+
+    $ mdns-demo
+
+You should see output similar to:
+
+.. code-block:: console
+
+    Run this from another console to start another peer on a different port:
+
+    python mdns-demo -p <ANOTHER_PORT>
+
+    Waiting for mDNS peer discovery events...
+
+    2025-06-20 23:28:12,052 - libp2p.example.discovery.mdns - INFO - Starting peer Discovery
+
+To discover peers, open another terminal and run the same command with a different port:
+
+.. code-block:: console
+
+    $ python mdns-demo -p 9001
+
+You should see output indicating that a new peer has been discovered:
+
+.. code-block:: console
+
+    Run this from the same folder in another console to start another peer on a different port:
+
+    python mdns-demo -p <ANOTHER_PORT>
+
+    Waiting for mDNS peer discovery events...
+
+    2025-06-20 23:43:43,786 - libp2p.example.discovery.mdns - INFO - Starting peer Discovery
+    2025-06-20 23:43:43,790 - libp2p.example.discovery.mdns - INFO - Discovered: 16Uiu2HAmGxy5NdQEjZWtrYUMrzdp3Syvg7MB2E5Lx8weA9DanYxj
+
+When a new peer is discovered, its peer ID will be printed in the console output.
+
+How it Works
+------------
+
+- Each node advertises itself on the local network using mDNS.
+- When a new peer is discovered, the handler prints its peer ID.
+- This is useful for local peer discovery without requiring a DHT or bootstrap nodes.
+
+You can modify the script to perform additional actions when peers are discovered, such as opening streams or exchanging messages.

docs/examples.rst

@@ -13,3 +13,4 @@ Examples
    examples.pubsub
    examples.circuit_relay
    examples.kademlia
+   examples.mDNS

docs/libp2p.discovery.events.rst

@@ -0,0 +1,21 @@
+libp2p.discovery.events package
+===============================
+
+Submodules
+----------
+
+libp2p.discovery.events.peerDiscovery module
+--------------------------------------------
+
+.. automodule:: libp2p.discovery.events.peerDiscovery
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+Module contents
+---------------
+
+.. automodule:: libp2p.discovery.events
+   :members:
+   :undoc-members:
+   :show-inheritance:

docs/libp2p.discovery.mdns.rst

@@ -0,0 +1,45 @@
+libp2p.discovery.mdns package
+=============================
+
+Submodules
+----------
+
+libp2p.discovery.mdns.broadcaster module
+----------------------------------------
+
+.. automodule:: libp2p.discovery.mdns.broadcaster
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+libp2p.discovery.mdns.listener module
+-------------------------------------
+
+.. automodule:: libp2p.discovery.mdns.listener
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+libp2p.discovery.mdns.mdns module
+---------------------------------
+
+.. automodule:: libp2p.discovery.mdns.mdns
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+libp2p.discovery.mdns.utils module
+----------------------------------
+
+.. automodule:: libp2p.discovery.mdns.utils
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
+Module contents
+---------------
+
+.. automodule:: libp2p.discovery.mdns
+   :members:
+   :undoc-members:
+   :show-inheritance:

docs/libp2p.discovery.rst

@@ -0,0 +1,22 @@
+libp2p.discovery package
+========================
+
+Subpackages
+-----------
+
+.. toctree::
+   :maxdepth: 4
+
+   libp2p.discovery.events
+   libp2p.discovery.mdns
+
+Submodules
+----------
+
+Module contents
+---------------
+
+.. automodule:: libp2p.discovery
+   :members:
+   :undoc-members:
+   :show-inheritance:

docs/libp2p.rst

@@ -8,6 +8,7 @@ Subpackages
    :maxdepth: 4
 
    libp2p.crypto
+   libp2p.discovery
    libp2p.host
    libp2p.identity
    libp2p.io

examples/mDNS/mDNS.py

@@ -0,0 +1,74 @@
+import argparse
+import logging
+import secrets
+
+import multiaddr
+import trio
+
+from libp2p import (
+    new_host,
+)
+from libp2p.abc import PeerInfo
+from libp2p.crypto.secp256k1 import (
+    create_new_key_pair,
+)
+from libp2p.discovery.events.peerDiscovery import peerDiscovery
+
+logger = logging.getLogger("libp2p.discovery.mdns")
+logger.setLevel(logging.INFO)
+handler = logging.StreamHandler()
+handler.setFormatter(
+    logging.Formatter("%(asctime)s - %(name)s - %(levelname)s - %(message)s")
+)
+logger.addHandler(handler)
+
+# Set root logger to DEBUG to capture all logs from dependencies
+logging.getLogger().setLevel(logging.DEBUG)
+
+
+def onPeerDiscovery(peerinfo: PeerInfo):
+    logger.info(f"Discovered: {peerinfo.peer_id}")
+
+
+async def run(port: int) -> None:
+    secret = secrets.token_bytes(32)
+    key_pair = create_new_key_pair(secret)
+    listen_addr = multiaddr.Multiaddr(f"/ip4/0.0.0.0/tcp/{port}")
+
+    peerDiscovery.register_peer_discovered_handler(onPeerDiscovery)
+
+    print(
+        "Run this from the same folder in another console to "
+        "start another peer on a different port:\n\n"
+        "mdns-demo -p <ANOTHER_PORT>\n"
+    )
+    print("Waiting for mDNS peer discovery events...\n")
+
+    logger.info("Starting peer Discovery")
+    host = new_host(key_pair=key_pair, enable_mDNS=True)
+    async with host.run(listen_addrs=[listen_addr]):
+        await trio.sleep_forever()
+
+
+def main() -> None:
+    description = """
+    This program demonstrates mDNS peer discovery using libp2p.
+    To use it, run 'mdns-demo -p <PORT>', where <PORT> is the port number.
+    Start multiple peers on different ports to see discovery in action.
+    """
+    parser = argparse.ArgumentParser(description=description)
+    parser.add_argument("-p", "--port", default=0, type=int, help="source port number")
+    parser.add_argument(
+        "-v", "--verbose", action="store_true", help="Enable verbose output"
+    )
+    args = parser.parse_args()
+    if args.verbose:
+        logger.setLevel(logging.DEBUG)
+    try:
+        trio.run(run, args.port)
+    except KeyboardInterrupt:
+        logger.info("Exiting...")
+
+
+if __name__ == "__main__":
+    main()

libp2p/__init__.py

@@ -32,6 +32,9 @@
     TProtocol,
     TSecurityOptions,
 )
+from libp2p.discovery.mdns.mdns import (
+    MDNSDiscovery,
+)
 from libp2p.host.basic_host import (
     BasicHost,
 )
@@ -245,6 +248,7 @@ def new_host(
     disc_opt: IPeerRouting | None = None,
     muxer_preference: Literal["YAMUX", "MPLEX"] | None = None,
     listen_addrs: Sequence[multiaddr.Multiaddr] | None = None,
+    enable_mDNS: bool = False,
 ) -> IHost:
     """
     Create a new libp2p host based on the given parameters.
@@ -256,6 +260,7 @@ def new_host(
     :param disc_opt: optional discovery
     :param muxer_preference: optional explicit muxer preference
     :param listen_addrs: optional list of multiaddrs to listen on
+    :param enable_mDNS: whether to enable mDNS discovery
     :return: return a host instance
     """
     swarm = new_swarm(
@@ -268,8 +273,7 @@ def new_host(
     )
 
     if disc_opt is not None:
-        return RoutedHost(swarm, disc_opt)
-    return BasicHost(swarm)
-
+        return RoutedHost(swarm, disc_opt, enable_mDNS)
+    return BasicHost(swarm, enable_mDNS)
 
 __version__ = __version("libp2p")