Source code for airflow.providers.apache.hdfs.sensors.hdfs

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import logging
import re
import sys
from typing import TYPE_CHECKING, Any, Dict, List, Optional, Pattern, Sequence, Type

from airflow import settings
from airflow.providers.apache.hdfs.hooks.hdfs import HDFSHook
from airflow.sensors.base import BaseSensorOperator

if TYPE_CHECKING:
    from airflow.utils.context import Context

[docs]log = logging.getLogger(__name__)
[docs]class HdfsSensor(BaseSensorOperator): """ Waits for a file or folder to land in HDFS :param filepath: The route to a stored file. :param hdfs_conn_id: The Airflow connection used for HDFS credentials. :param ignored_ext: This is the list of ignored extensions. :param ignore_copying: Shall we ignore? :param file_size: This is the size of the file. .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:HdfsSensor` """
[docs] template_fields: Sequence[str] = ('filepath',)
[docs] ui_color = settings.WEB_COLORS['LIGHTBLUE']
def __init__( self, *, filepath: str, hdfs_conn_id: str = 'hdfs_default', ignored_ext: Optional[List[str]] = None, ignore_copying: bool = True, file_size: Optional[int] = None, hook: Type[HDFSHook] = HDFSHook, **kwargs: Any, ) -> None: super().__init__(**kwargs) if ignored_ext is None: ignored_ext = ['_COPYING_'] self.filepath = filepath self.hdfs_conn_id = hdfs_conn_id self.file_size = file_size self.ignored_ext = ignored_ext self.ignore_copying = ignore_copying self.hook = hook @staticmethod
[docs] def filter_for_filesize(result: List[Dict[Any, Any]], size: Optional[int] = None) -> List[Dict[Any, Any]]: """ Will test the filepath result and test if its size is at least self.filesize :param result: a list of dicts returned by Snakebite ls :param size: the file size in MB a file should be at least to trigger True :return: (bool) depending on the matching criteria """ if size: log.debug('Filtering for file size >= %s in files: %s', size, map(lambda x: x['path'], result)) size *= settings.MEGABYTE result = [x for x in result if x['length'] >= size] log.debug('HdfsSensor.poke: after size filter result is %s', result) return result
@staticmethod
[docs] def filter_for_ignored_ext( result: List[Dict[Any, Any]], ignored_ext: List[str], ignore_copying: bool ) -> List[Dict[Any, Any]]: """ Will filter if instructed to do so the result to remove matching criteria :param result: list of dicts returned by Snakebite ls :param ignored_ext: list of ignored extensions :param ignore_copying: shall we ignore ? :return: list of dicts which were not removed :rtype: list[dict] """ if ignore_copying: regex_builder = r"^.*\.(%s$)$" % '$|'.join(ignored_ext) ignored_extensions_regex = re.compile(regex_builder) log.debug( 'Filtering result for ignored extensions: %s in files %s', ignored_extensions_regex.pattern, map(lambda x: x['path'], result), ) result = [x for x in result if not ignored_extensions_regex.match(x['path'])] log.debug('HdfsSensor.poke: after ext filter result is %s', result) return result
[docs] def poke(self, context: "Context") -> bool: """Get a snakebite client connection and check for file.""" sb_client = self.hook(self.hdfs_conn_id).get_conn() self.log.info('Poking for file %s', self.filepath) try: # IMOO it's not right here, as there is no raise of any kind. # if the filepath is let's say '/data/mydirectory', # it's correct but if it is '/data/mydirectory/*', # it's not correct as the directory exists and sb_client does not raise any error # here is a quick fix result = sb_client.ls([self.filepath], include_toplevel=False) self.log.debug('HdfsSensor.poke: result is %s', result) result = self.filter_for_ignored_ext(result, self.ignored_ext, self.ignore_copying) result = self.filter_for_filesize(result, self.file_size) return bool(result) except Exception: e = sys.exc_info() self.log.debug("Caught an exception !: %s", str(e)) return False
[docs]class HdfsRegexSensor(HdfsSensor): """ Waits for matching files by matching on regex .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:HdfsRegexSensor` """ def __init__(self, regex: Pattern[str], *args: Any, **kwargs: Any) -> None: super().__init__(*args, **kwargs) self.regex = regex
[docs] def poke(self, context: "Context") -> bool: """ Poke matching files in a directory with self.regex :return: Bool depending on the search criteria """ sb_client = self.hook(self.hdfs_conn_id).get_conn() self.log.info( 'Poking for %s to be a directory with files matching %s', self.filepath, self.regex.pattern ) result = [ f for f in sb_client.ls([self.filepath], include_toplevel=False) if f['file_type'] == 'f' and self.regex.match(f['path'].replace(f'{self.filepath}/', '')) ] result = self.filter_for_ignored_ext(result, self.ignored_ext, self.ignore_copying) result = self.filter_for_filesize(result, self.file_size) return bool(result)
[docs]class HdfsFolderSensor(HdfsSensor): """ Waits for a non-empty directory .. seealso:: For more information on how to use this operator, take a look at the guide: :ref:`howto/operator:HdfsFolderSensor` """ def __init__(self, be_empty: bool = False, *args: Any, **kwargs: Any): super().__init__(*args, **kwargs) self.be_empty = be_empty
[docs] def poke(self, context: "Context") -> bool: """ Poke for a non empty directory :return: Bool depending on the search criteria """ sb_client = self.hook(self.hdfs_conn_id).get_conn() result = sb_client.ls([self.filepath], include_toplevel=True) result = self.filter_for_ignored_ext(result, self.ignored_ext, self.ignore_copying) result = self.filter_for_filesize(result, self.file_size) if self.be_empty: self.log.info('Poking for filepath %s to a empty directory', self.filepath) return len(result) == 1 and result[0]['path'] == self.filepath else: self.log.info('Poking for filepath %s to a non empty directory', self.filepath) result.pop(0) return bool(result) and result[0]['file_type'] == 'f'

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