259 lines
8.9 KiB
Python
259 lines
8.9 KiB
Python
"""
|
|
Package for interacting on the network at a high level.
|
|
"""
|
|
import random
|
|
import pickle
|
|
import asyncio
|
|
import logging
|
|
|
|
from kademlia.protocol import KademliaProtocol
|
|
from kademlia.utils import digest
|
|
from kademlia.storage import ForgetfulStorage
|
|
from kademlia.node import Node
|
|
from kademlia.crawling import ValueSpiderCrawl
|
|
from kademlia.crawling import NodeSpiderCrawl
|
|
|
|
log = logging.getLogger(__name__)
|
|
|
|
|
|
class Server(object):
|
|
"""
|
|
High level view of a node instance. This is the object that should be
|
|
created to start listening as an active node on the network.
|
|
"""
|
|
|
|
protocol_class = KademliaProtocol
|
|
|
|
def __init__(self, ksize=20, alpha=3, node_id=None, storage=None):
|
|
"""
|
|
Create a server instance. This will start listening on the given port.
|
|
|
|
Args:
|
|
ksize (int): The k parameter from the paper
|
|
alpha (int): The alpha parameter from the paper
|
|
node_id: The id for this node on the network.
|
|
storage: An instance that implements
|
|
:interface:`~kademlia.storage.IStorage`
|
|
"""
|
|
self.ksize = ksize
|
|
self.alpha = alpha
|
|
self.storage = storage or ForgetfulStorage()
|
|
self.node = Node(node_id or digest(random.getrandbits(255)))
|
|
self.transport = None
|
|
self.protocol = None
|
|
self.refresh_loop = None
|
|
self.save_state_loop = None
|
|
|
|
def stop(self):
|
|
if self.transport is not None:
|
|
self.transport.close()
|
|
|
|
if self.refresh_loop:
|
|
self.refresh_loop.cancel()
|
|
|
|
if self.save_state_loop:
|
|
self.save_state_loop.cancel()
|
|
|
|
def _create_protocol(self):
|
|
return self.protocol_class(self.node, self.storage, self.ksize)
|
|
|
|
def listen(self, port, interface='0.0.0.0'):
|
|
"""
|
|
Start listening on the given port.
|
|
|
|
Provide interface="::" to accept ipv6 address
|
|
"""
|
|
loop = asyncio.get_event_loop()
|
|
listen = loop.create_datagram_endpoint(self._create_protocol,
|
|
local_addr=(interface, port))
|
|
log.info("Node %i listening on %s:%i",
|
|
self.node.long_id, interface, port)
|
|
self.transport, self.protocol = loop.run_until_complete(listen)
|
|
# finally, schedule refreshing table
|
|
self.refresh_table()
|
|
|
|
def refresh_table(self):
|
|
log.debug("Refreshing routing table")
|
|
asyncio.ensure_future(self._refresh_table())
|
|
loop = asyncio.get_event_loop()
|
|
self.refresh_loop = loop.call_later(3600, self.refresh_table)
|
|
|
|
async def _refresh_table(self):
|
|
"""
|
|
Refresh buckets that haven't had any lookups in the last hour
|
|
(per section 2.3 of the paper).
|
|
"""
|
|
ds = []
|
|
for node_id in self.protocol.getRefreshIDs():
|
|
node = Node(node_id)
|
|
nearest = self.protocol.router.findNeighbors(node, self.alpha)
|
|
spider = NodeSpiderCrawl(self.protocol, node, nearest,
|
|
self.ksize, self.alpha)
|
|
ds.append(spider.find())
|
|
|
|
# do our crawling
|
|
await asyncio.gather(*ds)
|
|
|
|
# now republish keys older than one hour
|
|
for dkey, value in self.storage.iteritemsOlderThan(3600):
|
|
await self.set_digest(dkey, value)
|
|
|
|
def bootstrappableNeighbors(self):
|
|
"""
|
|
Get a :class:`list` of (ip, port) :class:`tuple` pairs suitable for
|
|
use as an argument to the bootstrap method.
|
|
|
|
The server should have been bootstrapped
|
|
already - this is just a utility for getting some neighbors and then
|
|
storing them if this server is going down for a while. When it comes
|
|
back up, the list of nodes can be used to bootstrap.
|
|
"""
|
|
neighbors = self.protocol.router.findNeighbors(self.node)
|
|
return [tuple(n)[-2:] for n in neighbors]
|
|
|
|
async def bootstrap(self, addrs):
|
|
"""
|
|
Bootstrap the server by connecting to other known nodes in the network.
|
|
|
|
Args:
|
|
addrs: A `list` of (ip, port) `tuple` pairs. Note that only IP
|
|
addresses are acceptable - hostnames will cause an error.
|
|
"""
|
|
log.debug("Attempting to bootstrap node with %i initial contacts",
|
|
len(addrs))
|
|
cos = list(map(self.bootstrap_node, addrs))
|
|
gathered = await asyncio.gather(*cos)
|
|
nodes = [node for node in gathered if node is not None]
|
|
spider = NodeSpiderCrawl(self.protocol, self.node, nodes,
|
|
self.ksize, self.alpha)
|
|
return await spider.find()
|
|
|
|
async def bootstrap_node(self, addr):
|
|
result = await self.protocol.ping(addr, self.node.id)
|
|
return Node(result[1], addr[0], addr[1]) if result[0] else None
|
|
|
|
async def get(self, key):
|
|
"""
|
|
Get a key if the network has it.
|
|
|
|
Returns:
|
|
:class:`None` if not found, the value otherwise.
|
|
"""
|
|
log.info("Looking up key %s", key)
|
|
dkey = digest(key)
|
|
# if this node has it, return it
|
|
if self.storage.get(dkey) is not None:
|
|
return self.storage.get(dkey)
|
|
node = Node(dkey)
|
|
nearest = self.protocol.router.findNeighbors(node)
|
|
if len(nearest) == 0:
|
|
log.warning("There are no known neighbors to get key %s", key)
|
|
return None
|
|
spider = ValueSpiderCrawl(self.protocol, node, nearest,
|
|
self.ksize, self.alpha)
|
|
return await spider.find()
|
|
|
|
async def set(self, key, value):
|
|
"""
|
|
Set the given string key to the given value in the network.
|
|
"""
|
|
if not check_dht_value_type(value):
|
|
raise TypeError(
|
|
"Value must be of type int, float, bool, str, or bytes"
|
|
)
|
|
log.info("setting '%s' = '%s' on network", key, value)
|
|
dkey = digest(key)
|
|
return await self.set_digest(dkey, value)
|
|
|
|
async def set_digest(self, dkey, value):
|
|
"""
|
|
Set the given SHA1 digest key (bytes) to the given value in the
|
|
network.
|
|
"""
|
|
node = Node(dkey)
|
|
|
|
nearest = self.protocol.router.findNeighbors(node)
|
|
if len(nearest) == 0:
|
|
log.warning("There are no known neighbors to set key %s",
|
|
dkey.hex())
|
|
return False
|
|
|
|
spider = NodeSpiderCrawl(self.protocol, node, nearest,
|
|
self.ksize, self.alpha)
|
|
nodes = await spider.find()
|
|
log.info("setting '%s' on %s", dkey.hex(), list(map(str, nodes)))
|
|
|
|
# if this node is close too, then store here as well
|
|
biggest = max([n.distanceTo(node) for n in nodes])
|
|
if self.node.distanceTo(node) < biggest:
|
|
self.storage[dkey] = value
|
|
ds = [self.protocol.callStore(n, dkey, value) for n in nodes]
|
|
# return true only if at least one store call succeeded
|
|
return any(await asyncio.gather(*ds))
|
|
|
|
def saveState(self, fname):
|
|
"""
|
|
Save the state of this node (the alpha/ksize/id/immediate neighbors)
|
|
to a cache file with the given fname.
|
|
"""
|
|
log.info("Saving state to %s", fname)
|
|
data = {
|
|
'ksize': self.ksize,
|
|
'alpha': self.alpha,
|
|
'id': self.node.id,
|
|
'neighbors': self.bootstrappableNeighbors()
|
|
}
|
|
if len(data['neighbors']) == 0:
|
|
log.warning("No known neighbors, so not writing to cache.")
|
|
return
|
|
with open(fname, 'wb') as f:
|
|
pickle.dump(data, f)
|
|
|
|
@classmethod
|
|
def loadState(self, fname):
|
|
"""
|
|
Load the state of this node (the alpha/ksize/id/immediate neighbors)
|
|
from a cache file with the given fname.
|
|
"""
|
|
log.info("Loading state from %s", fname)
|
|
with open(fname, 'rb') as f:
|
|
data = pickle.load(f)
|
|
s = Server(data['ksize'], data['alpha'], data['id'])
|
|
if len(data['neighbors']) > 0:
|
|
s.bootstrap(data['neighbors'])
|
|
return s
|
|
|
|
def saveStateRegularly(self, fname, frequency=600):
|
|
"""
|
|
Save the state of node with a given regularity to the given
|
|
filename.
|
|
|
|
Args:
|
|
fname: File name to save retularly to
|
|
frequency: Frequency in seconds that the state should be saved.
|
|
By default, 10 minutes.
|
|
"""
|
|
self.saveState(fname)
|
|
loop = asyncio.get_event_loop()
|
|
self.save_state_loop = loop.call_later(frequency,
|
|
self.saveStateRegularly,
|
|
fname,
|
|
frequency)
|
|
|
|
|
|
def check_dht_value_type(value):
|
|
"""
|
|
Checks to see if the type of the value is a valid type for
|
|
placing in the dht.
|
|
"""
|
|
typeset = set(
|
|
[
|
|
int,
|
|
float,
|
|
bool,
|
|
str,
|
|
bytes,
|
|
]
|
|
)
|
|
return type(value) in typeset
|