|
| 1 | +"""Native Delayed Delivery API. |
| 2 | +
|
| 3 | +Only relevant for RabbitMQ. |
| 4 | +""" |
| 5 | +from __future__ import annotations |
| 6 | + |
| 7 | +from kombu import Connection, Exchange, Queue |
| 8 | +from kombu.log import get_logger |
| 9 | + |
| 10 | +logger = get_logger(__name__) |
| 11 | + |
| 12 | +MAX_NUMBER_OF_BITS_TO_USE = 28 |
| 13 | +MAX_LEVEL = MAX_NUMBER_OF_BITS_TO_USE - 1 |
| 14 | +CELERY_DELAYED_DELIVERY_EXCHANGE = "celery_delayed_delivery" |
| 15 | + |
| 16 | + |
| 17 | +def level_name(level: int) -> str: |
| 18 | + """Generates the delayed queue/exchange name based on the level.""" |
| 19 | + if level < 0: |
| 20 | + raise ValueError("level must be a non-negative number") |
| 21 | + |
| 22 | + return f"celery_delayed_{level}" |
| 23 | + |
| 24 | + |
| 25 | +def declare_native_delayed_delivery_exchanges_and_queues(connection: Connection, queue_type: str) -> None: |
| 26 | + """Declares all native delayed delivery exchanges and queues.""" |
| 27 | + if queue_type != "classic" and queue_type != "quorum": |
| 28 | + raise ValueError("queue_type must be either classic or quorum") |
| 29 | + |
| 30 | + channel = connection.channel() |
| 31 | + |
| 32 | + routing_key: str = "1.#" |
| 33 | + |
| 34 | + for level in range(27, -1, - 1): |
| 35 | + current_level = level_name(level) |
| 36 | + next_level = level_name(level - 1) if level > 0 else None |
| 37 | + |
| 38 | + delayed_exchange: Exchange = Exchange( |
| 39 | + current_level, type="topic").bind(channel) |
| 40 | + delayed_exchange.declare() |
| 41 | + |
| 42 | + queue_arguments = { |
| 43 | + "x-queue-type": queue_type, |
| 44 | + "x-overflow": "reject-publish", |
| 45 | + "x-message-ttl": pow(2, level) * 1000, |
| 46 | + "x-dead-letter-exchange": next_level if level > 0 else CELERY_DELAYED_DELIVERY_EXCHANGE, |
| 47 | + } |
| 48 | + |
| 49 | + if queue_type == 'quorum': |
| 50 | + queue_arguments["x-dead-letter-strategy"] = "at-least-once" |
| 51 | + |
| 52 | + delayed_queue: Queue = Queue( |
| 53 | + current_level, |
| 54 | + queue_arguments=queue_arguments |
| 55 | + ).bind(channel) |
| 56 | + delayed_queue.declare() |
| 57 | + delayed_queue.bind_to(current_level, routing_key) |
| 58 | + |
| 59 | + routing_key = "*." + routing_key |
| 60 | + |
| 61 | + routing_key = "0.#" |
| 62 | + for level in range(27, 0, - 1): |
| 63 | + current_level = level_name(level) |
| 64 | + next_level = level_name(level - 1) if level > 0 else None |
| 65 | + |
| 66 | + next_level_exchange: Exchange = Exchange( |
| 67 | + next_level, type="topic").bind(channel) |
| 68 | + |
| 69 | + next_level_exchange.bind_to(current_level, routing_key) |
| 70 | + |
| 71 | + routing_key = "*." + routing_key |
| 72 | + |
| 73 | + delivery_exchange: Exchange = Exchange( |
| 74 | + CELERY_DELAYED_DELIVERY_EXCHANGE, type="topic").bind(channel) |
| 75 | + delivery_exchange.declare() |
| 76 | + delivery_exchange.bind_to(level_name(0), routing_key) |
| 77 | + |
| 78 | + |
| 79 | +def bind_queue_to_native_delayed_delivery_exchange(connection: Connection, queue: Queue) -> None: |
| 80 | + """Binds a queue to the native delayed delivery exchange.""" |
| 81 | + channel = connection.channel() |
| 82 | + queue = queue.bind(channel) |
| 83 | + exchange: Exchange = queue.exchange.bind(channel) |
| 84 | + |
| 85 | + if exchange.type == 'direct': |
| 86 | + logger.warn(f"Exchange {exchange.name} is a direct exchange " |
| 87 | + f"and native delayed delivery do not support direct exchanges.\n" |
| 88 | + f"ETA tasks published to this exchange will block the worker until the ETA arrives.") |
| 89 | + return |
| 90 | + |
| 91 | + routing_key = queue.routing_key if queue.routing_key.startswith( |
| 92 | + '#') else f"#.{queue.routing_key}" |
| 93 | + exchange.bind_to(CELERY_DELAYED_DELIVERY_EXCHANGE, routing_key=routing_key) |
| 94 | + queue.bind_to(exchange.name, routing_key=routing_key) |
| 95 | + |
| 96 | + |
| 97 | +def calculate_routing_key(countdown: int, routing_key: str) -> str: |
| 98 | + """Calculate the routing key for publishing a delayed message based on the countdown.""" |
| 99 | + if countdown < 1: |
| 100 | + raise ValueError("countdown must be a positive number") |
| 101 | + |
| 102 | + if not routing_key: |
| 103 | + raise ValueError("routing_key must be non-empty") |
| 104 | + |
| 105 | + return '.'.join(list(f'{countdown:028b}')) + f'.{routing_key}' |
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