03be75abca
It holds the subscriptions in a tree fashion, sending the message down the branches while broadcasting on each node.
87 lines
2.9 KiB
Python
87 lines
2.9 KiB
Python
"""Websocket functionality."""
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import logging
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from fastapi import WebSocket
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from spoolman.api.v1.models import Event
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logger = logging.getLogger(__name__)
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class SubscriptionTree:
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"""Subscription tree.
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This is a tree structure that allows us to efficiently send messages to
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all websockets that are subscribed to a certain pool of events.
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You can subscribe to different levels of the tree, for example:
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- ("vendor", "1") will subscribe to events for vendor 1
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- ("vendor") will subscribe to events for all vendors
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- () will subscribe to events for all vendors, filaments and spools
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"""
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def __init__(self) -> None:
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"""Initialize."""
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self.children: dict[str, SubscriptionTree] = {}
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self.subscribers: set[WebSocket] = set()
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def add(self, path: tuple[str, ...], websocket: WebSocket) -> None:
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"""Add a websocket to the subscription tree."""
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if len(path) == 0:
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self.subscribers.add(websocket)
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else:
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if path[0] not in self.children:
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self.children[path[0]] = SubscriptionTree()
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self.children[path[0]].add(path[1:], websocket)
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def remove(self, path: tuple[str, ...], websocket: WebSocket) -> None:
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"""Remove a websocket from the subscription tree."""
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if len(path) == 0:
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self.subscribers.remove(websocket)
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elif path[0] in self.children:
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self.children[path[0]].remove(path[1:], websocket)
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async def send(self, path: tuple[str, ...], evt: Event) -> None:
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"""Send a message to all websockets in this branch of the tree."""
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# Broadcast to all subscribers on this level
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for websocket in self.subscribers:
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await websocket.send_text(evt.json())
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# Send the message further down the tree
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if len(path) > 0 and path[0] in self.children:
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await self.children[path[0]].send(path[1:], evt)
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class WebsocketManager:
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"""Websocket manager."""
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def __init__(self) -> None:
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"""Initialize."""
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self.tree = SubscriptionTree()
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def connect(self, pool: tuple[str, ...], websocket: WebSocket) -> None:
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"""Connect a websocket."""
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self.tree.add(pool, websocket)
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logger.info(
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"Client %s is now listening on pool %s",
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websocket.client.host if websocket.client else "?",
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",".join(pool),
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)
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def disconnect(self, pool: tuple[str, ...], websocket: WebSocket) -> None:
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"""Disconnect a websocket."""
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self.tree.remove(pool, websocket)
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logger.info(
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"Client %s has stopped listening on pool %s",
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websocket.client.host if websocket.client else "?",
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",".join(pool),
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)
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async def send(self, pool: tuple[str, ...], evt: Event) -> None:
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"""Send a message to all websockets in a pool."""
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await self.tree.send(pool, evt)
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websocket_manager = WebsocketManager()
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