51 lines
1.7 KiB
Python
51 lines
1.7 KiB
Python
"""Periodic OBSERVE re-subscribe.
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CoAP OBSERVE (RFC 7641) has no built-in TTL, but real-world peers age
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out observer state on their own schedule — Samsung's RT-OCF is known
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to silently drop notify delivery during cloud auth blips even though
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the DTLS session stays healthy. Without a re-subscribe, recovery from
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such a blip requires a full session reconnect.
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This task derregisters the current observer tokens and re-subscribes
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every `interval_s`. Cheap (one register CON per path), idempotent
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(Samsung silently no-ops a register on an already-active token), and
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resilient — individual subscribe failures are logged but don't abort
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the task.
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"""
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from __future__ import annotations
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import threading
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from typing import Optional
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from protocol.dtls_session import DtlsCoapSession
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class ObserveRefreshTask:
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def __init__(self,
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session: DtlsCoapSession,
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paths,
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interval_s: float = 6 * 3600.0,
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logger=None):
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self.session = session
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self.paths = [list(p) for p in paths]
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self.interval_s = interval_s
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self.log = logger
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self._refresh_count = 0
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@property
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def refresh_count(self) -> int:
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return self._refresh_count
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def run_forever(self, stop: threading.Event) -> None:
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while not stop.wait(self.interval_s):
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try:
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self.session.refresh_observes(self.paths)
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self._refresh_count += 1
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if self.log:
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self.log.info("OBSERVE refresh #%d (%d paths)",
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self._refresh_count, len(self.paths))
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except Exception as e:
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if self.log:
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self.log.warning("OBSERVE refresh: %s", e)
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