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from __future__ import annotations
import datetime
import os
from functools import cached_property
from glob import glob
from typing import TYPE_CHECKING, Any, Sequence
from airflow.configuration import conf
from airflow.exceptions import AirflowException
from airflow.hooks.filesystem import FSHook
from airflow.sensors.base import BaseSensorOperator
from airflow.triggers.base import StartTriggerArgs
from airflow.triggers.file import FileTrigger
if TYPE_CHECKING:
from airflow.utils.context import Context
[docs]class FileSensor(BaseSensorOperator):
"""
Waits for a file or folder to land in a filesystem.
If the path given is a directory then this sensor will only return true if
any files exist inside it (either directly, or within a subdirectory)
:param fs_conn_id: reference to the File (path)
connection id
:param filepath: File or folder name (relative to
the base path set within the connection), can be a glob.
:param recursive: when set to ``True``, enables recursive directory matching behavior of
``**`` in glob filepath parameter. Defaults to ``False``.
:param deferrable: If waiting for completion, whether to defer the task until done,
default is ``False``.
:param start_from_trigger: Start the task directly from the triggerer without going into the worker.
:param trigger_kwargs: The keyword arguments passed to the trigger when start_from_trigger is set to True
during dynamic task mapping. This argument is not used in standard usage.
.. seealso::
For more information on how to use this sensor, take a look at the guide:
:ref:`howto/operator:FileSensor`
"""
[docs] template_fields: Sequence[str] = ("filepath",)
[docs] start_trigger_args = StartTriggerArgs(
trigger_cls="airflow.triggers.file.FileTrigger",
trigger_kwargs={},
next_method="execute_complete",
next_kwargs=None,
timeout=None,
)
[docs] start_from_trigger = False
def __init__(
self,
*,
filepath,
fs_conn_id="fs_default",
recursive=False,
deferrable: bool = conf.getboolean("operators", "default_deferrable", fallback=False),
start_from_trigger: bool = False,
trigger_kwargs: dict[str, Any] | None = None,
**kwargs,
):
super().__init__(**kwargs)
self.filepath = filepath
self.fs_conn_id = fs_conn_id
self.recursive = recursive
self.deferrable = deferrable
self.start_from_trigger = start_from_trigger
if self.deferrable and self.start_from_trigger:
self.start_trigger_args.timeout = datetime.timedelta(seconds=self.timeout)
self.start_trigger_args.trigger_kwargs = dict(
filepath=self.path,
recursive=self.recursive,
poke_interval=self.poke_interval,
)
@cached_property
[docs] def path(self) -> str:
hook = FSHook(self.fs_conn_id)
basepath = hook.get_path()
full_path = os.path.join(basepath, self.filepath)
return full_path
[docs] def poke(self, context: Context) -> bool:
self.log.info("Poking for file %s", self.path)
for path in glob(self.path, recursive=self.recursive):
if os.path.isfile(path):
mod_time = datetime.datetime.fromtimestamp(os.path.getmtime(path)).strftime("%Y%m%d%H%M%S")
self.log.info("Found File %s last modified: %s", path, mod_time)
return True
for _, _, files in os.walk(path):
if files:
return True
return False
[docs] def execute(self, context: Context) -> None:
if not self.deferrable:
super().execute(context=context)
if not self.poke(context=context):
self.defer(
timeout=datetime.timedelta(seconds=self.timeout),
trigger=FileTrigger(
filepath=self.path,
recursive=self.recursive,
poke_interval=self.poke_interval,
),
method_name="execute_complete",
)
[docs] def execute_complete(self, context: Context, event: bool | None = None) -> None:
if not event:
raise AirflowException("%s task failed as %s not found.", self.task_id, self.filepath)
self.log.info("%s completed successfully as %s found.", self.task_id, self.filepath)