Python Distributed Hash Table

Documentation can be found at kademlia.readthedocs.org.

This library is an asynchronous Python implementation of the Kademlia distributed hash table. It uses the asyncio library in Python 3 to provide asynchronous communication. The nodes communicate using RPC over UDP to communiate, meaning that it is capable of working behind a NAT.

This library aims to be as close to a reference implementation of the Kademlia paper as possible.

Installation

pip install kademlia

Usage

This assumes you have a working familiarity with asyncio.

Assuming you want to connect to an existing network:

import asyncio
from kademlia.network import Server

# Create a node and start listening on port 5678
node = Server()
node.listen(5678)

# Bootstrap the node by connecting to other known nodes, in this case
# replace 123.123.123.123 with the IP of another node and optionally
# give as many ip/port combos as you can for other nodes.
loop = asyncio.get_event_loop()
loop.run_until_complete(node.bootstrap([("123.123.123.123", 5678)]))

# set a value for the key "my-key" on the network
loop.run_until_complete(node.set("my-key", "my awesome value"))

# get the value associated with "my-key" from the network
result = loop.run_until_complete(node.get("my-key"))
print(result)

Initializing a Network

If you're starting a new network from scratch, just omit the node.bootstrap call in the example above. Then, bootstrap other nodes by connecting to the first node you started.

See the examples folder for a first node example that other nodes can bootstrap connect to and some code that gets and sets a key/value.

Logging

This library uses the standard Python logging library. To see debut output printed to STDOUT, for instance, use:

import logging

log = logging.getLogger('kademlia')
log.setLevel(logging.DEBUG)
log.addHandler(logging.StreamHandler())

Running Tests

To run tests:

pip install -r dev-requirements.txt
python -m unittest

Fidelity to Original Paper

The current implementation should be an accurate implementation of all aspects of the paper save one - in Section 2.3 there is the requirement that the original publisher of a key/value republish it every 24 hours. This library does not do this (though you can easily do this manually).