136 lines
4.6 KiB
Python
136 lines
4.6 KiB
Python
from typing import AsyncIterator, Dict, Tuple
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from async_exit_stack import AsyncExitStack
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from async_generator import asynccontextmanager
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from async_service import Service, background_trio_service
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from libp2p.host.host_interface import IHost
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from libp2p.pubsub.pubsub import Pubsub
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from libp2p.tools.factories import PubsubFactory
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CRYPTO_TOPIC = "ethereum"
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# Message format:
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# Sending crypto: <source>,<dest>,<amount as integer>
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# Ex. send,aspyn,alex,5
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# Set crypto: <dest>,<amount as integer>
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# Ex. set,rob,5
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# Determine message type by looking at first item before first comma
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class DummyAccountNode(Service):
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"""
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Node which has an internal balance mapping, meant to serve as a dummy
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crypto blockchain.
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There is no actual blockchain, just a simple map indicating how much
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crypto each user in the mappings holds
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"""
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pubsub: Pubsub
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def __init__(self, pubsub: Pubsub) -> None:
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self.pubsub = pubsub
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self.balances: Dict[str, int] = {}
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@property
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def host(self) -> IHost:
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return self.pubsub.host
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async def run(self) -> None:
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self.subscription = await self.pubsub.subscribe(CRYPTO_TOPIC)
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self.manager.run_daemon_task(self.handle_incoming_msgs)
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await self.manager.wait_finished()
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@classmethod
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@asynccontextmanager
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async def create(cls, number: int) -> AsyncIterator[Tuple["DummyAccountNode", ...]]:
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"""
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Create a new DummyAccountNode and attach a libp2p node, a floodsub, and
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a pubsub instance to this new node.
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We use create as this serves as a factory function and allows us
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to use async await, unlike the init function
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"""
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async with PubsubFactory.create_batch_with_floodsub(number) as pubsubs:
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async with AsyncExitStack() as stack:
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dummy_acount_nodes = tuple(cls(pubsub) for pubsub in pubsubs)
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for node in dummy_acount_nodes:
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await stack.enter_async_context(background_trio_service(node))
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yield dummy_acount_nodes
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async def handle_incoming_msgs(self) -> None:
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"""Handle all incoming messages on the CRYPTO_TOPIC from peers."""
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while True:
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incoming = await self.subscription.get()
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msg_comps = incoming.data.decode("utf-8").split(",")
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if msg_comps[0] == "send":
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self.handle_send_crypto(msg_comps[1], msg_comps[2], int(msg_comps[3]))
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elif msg_comps[0] == "set":
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self.handle_set_crypto(msg_comps[1], int(msg_comps[2]))
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async def publish_send_crypto(
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self, source_user: str, dest_user: str, amount: int
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) -> None:
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"""
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Create a send crypto message and publish that message to all other
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nodes.
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:param source_user: user to send crypto from
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:param dest_user: user to send crypto to
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:param amount: amount of crypto to send
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"""
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msg_contents = f"send,{source_user},{dest_user},{amount!s}"
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await self.pubsub.publish(CRYPTO_TOPIC, msg_contents.encode())
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async def publish_set_crypto(self, user: str, amount: int) -> None:
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"""
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Create a set crypto message and publish that message to all other
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nodes.
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:param user: user to set crypto for
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:param amount: amount of crypto
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"""
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msg_contents = f"set,{user},{amount!s}"
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await self.pubsub.publish(CRYPTO_TOPIC, msg_contents.encode())
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def handle_send_crypto(self, source_user: str, dest_user: str, amount: int) -> None:
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"""
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Handle incoming send_crypto message.
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:param source_user: user to send crypto from
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:param dest_user: user to send crypto to
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:param amount: amount of crypto to send
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"""
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if source_user in self.balances:
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self.balances[source_user] -= amount
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else:
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self.balances[source_user] = -amount
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if dest_user in self.balances:
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self.balances[dest_user] += amount
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else:
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self.balances[dest_user] = amount
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def handle_set_crypto(self, dest_user: str, amount: int) -> None:
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"""
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Handle incoming set_crypto message.
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:param dest_user: user to set crypto for
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:param amount: amount of crypto
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"""
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self.balances[dest_user] = amount
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def get_balance(self, user: str) -> int:
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"""
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Get balance in crypto for a particular user.
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:param user: user to get balance for
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:return: balance of user
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"""
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if user in self.balances:
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return self.balances[user]
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else:
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return -1
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