| 376 | |
| 377 | |
| 378 | class SrvMonitor(MonitorBase): |
| 379 | def __init__(self, topology: Topology, topology_settings: TopologySettings): |
| 380 | """Class to poll SRV records on a background thread. |
| 381 | |
| 382 | Pass a Topology and a TopologySettings. |
| 383 | |
| 384 | The Topology is weakly referenced. |
| 385 | """ |
| 386 | super().__init__( |
| 387 | topology, |
| 388 | "pymongo_srv_polling_thread", |
| 389 | common.MIN_SRV_RESCAN_INTERVAL, |
| 390 | topology_settings.heartbeat_frequency, |
| 391 | ) |
| 392 | self._settings = topology_settings |
| 393 | self._seedlist = self._settings._seeds |
| 394 | assert isinstance(self._settings.fqdn, str) |
| 395 | self._fqdn: str = self._settings.fqdn |
| 396 | self._startup_time = time.monotonic() |
| 397 | |
| 398 | async def _run(self) -> None: |
| 399 | # Don't poll right after creation, wait 60 seconds first |
| 400 | if time.monotonic() < self._startup_time + common.MIN_SRV_RESCAN_INTERVAL: |
| 401 | return |
| 402 | seedlist = await self._get_seedlist() |
| 403 | if seedlist: |
| 404 | self._seedlist = seedlist |
| 405 | try: |
| 406 | await self._topology.on_srv_update(self._seedlist) |
| 407 | except ReferenceError: |
| 408 | # Topology was garbage-collected. |
| 409 | await self.close() |
| 410 | |
| 411 | async def _get_seedlist(self) -> Optional[list[tuple[str, Any]]]: |
| 412 | """Poll SRV records for a seedlist. |
| 413 | |
| 414 | Returns a list of ServerDescriptions. |
| 415 | """ |
| 416 | try: |
| 417 | resolver = _SrvResolver( |
| 418 | self._fqdn, |
| 419 | self._settings.pool_options.connect_timeout, |
| 420 | self._settings.srv_service_name, |
| 421 | ) |
| 422 | seedlist, ttl = await resolver.get_hosts_and_min_ttl() |
| 423 | if len(seedlist) == 0: |
| 424 | # As per the spec: this should be treated as a failure. |
| 425 | raise Exception |
| 426 | except Exception as exc: |
| 427 | # As per the spec, upon encountering an error: |
| 428 | # - An error must not be raised |
| 429 | # - SRV records must be rescanned every heartbeatFrequencyMS |
| 430 | # - Topology must be left unchanged |
| 431 | self.request_check() |
| 432 | _debug_log(_SDAM_LOGGER, message="SRV monitor check failed", failure=repr(exc)) |
| 433 | return None |
| 434 | else: |
| 435 | self._executor.update_interval(max(ttl, common.MIN_SRV_RESCAN_INTERVAL)) |