mirror of
https://github.com/trustgraph-ai/trustgraph.git
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182 lines
5 KiB
Python
182 lines
5 KiB
Python
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# Subscriber is similar to consumer: It provides a service to take stuff
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# off of a queue and make it available using an internal broker system,
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# so suitable for when multiple recipients are reading from the same queue
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from pulsar.schema import JsonSchema
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import asyncio
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import _pulsar
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import time
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import logging
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# Module logger
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logger = logging.getLogger(__name__)
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class Subscriber:
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def __init__(self, client, topic, subscription, consumer_name,
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schema=None, max_size=100, metrics=None):
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self.client = client
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self.topic = topic
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self.subscription = subscription
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self.consumer_name = consumer_name
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self.schema = schema
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self.q = {}
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self.full = {}
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self.max_size = max_size
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self.lock = asyncio.Lock()
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self.running = True
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self.metrics = metrics
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self.task = None
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self.consumer = None
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def __del__(self):
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self.running = False
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async def start(self):
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self.consumer = self.client.subscribe(
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topic = self.topic,
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subscription_name = self.subscription,
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consumer_name = self.consumer_name,
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schema = JsonSchema(self.schema),
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)
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self.task = asyncio.create_task(self.run())
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async def stop(self):
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self.running = False
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if self.task:
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await self.task
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async def join(self):
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await self.stop()
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if self.task:
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await self.task
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async def run(self):
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while self.running:
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if self.metrics:
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self.metrics.state("stopped")
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try:
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if self.metrics:
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self.metrics.state("running")
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logger.info("Subscriber running...")
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while self.running:
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try:
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msg = await asyncio.to_thread(
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self.consumer.receive,
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timeout_millis=250
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)
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except _pulsar.Timeout:
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continue
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except Exception as e:
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logger.error(f"Exception in subscriber receive: {e}", exc_info=True)
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raise e
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if self.metrics:
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self.metrics.received()
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# Acknowledge successful reception of the message
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self.consumer.acknowledge(msg)
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try:
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id = msg.properties()["id"]
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except:
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id = None
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value = msg.value()
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async with self.lock:
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# FIXME: Hard-coded timeouts
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if id in self.q:
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try:
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# FIXME: Timeout means data goes missing
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await asyncio.wait_for(
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self.q[id].put(value),
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timeout=1
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)
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except Exception as e:
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self.metrics.dropped()
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logger.warning(f"Failed to put message in queue: {e}")
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for q in self.full.values():
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try:
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# FIXME: Timeout means data goes missing
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await asyncio.wait_for(
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q.put(value),
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timeout=1
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)
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except Exception as e:
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self.metrics.dropped()
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logger.warning(f"Failed to put message in full queue: {e}")
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except Exception as e:
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logger.error(f"Subscriber exception: {e}", exc_info=True)
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finally:
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if self.consumer:
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self.consumer.unsubscribe()
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self.consumer.close()
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self.consumer = None
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if self.metrics:
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self.metrics.state("stopped")
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if not self.running:
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return
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# If handler drops out, sleep a retry
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await asyncio.sleep(1)
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async def subscribe(self, id):
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async with self.lock:
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q = asyncio.Queue(maxsize=self.max_size)
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self.q[id] = q
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return q
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async def unsubscribe(self, id):
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async with self.lock:
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if id in self.q:
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# self.q[id].shutdown(immediate=True)
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del self.q[id]
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async def subscribe_all(self, id):
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async with self.lock:
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q = asyncio.Queue(maxsize=self.max_size)
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self.full[id] = q
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return q
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async def unsubscribe_all(self, id):
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async with self.lock:
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if id in self.full:
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# self.full[id].shutdown(immediate=True)
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del self.full[id]
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