Source code for airflow.sensors.hdfs_sensor

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import re
import sys
from builtins import str

from airflow import settings
from airflow.hooks.hdfs_hook import HDFSHook
from airflow.sensors.base_sensor_operator import BaseSensorOperator
from airflow.utils.decorators import apply_defaults
from airflow.utils.log.logging_mixin import LoggingMixin

[docs]class HdfsSensor(BaseSensorOperator): """ Waits for a file or folder to land in HDFS """ template_fields = ('filepath',) ui_color = settings.WEB_COLORS['LIGHTBLUE'] @apply_defaults def __init__(self, filepath, hdfs_conn_id='hdfs_default', ignored_ext=['_COPYING_'], ignore_copying=True, file_size=None, hook=HDFSHook, *args, **kwargs): super(HdfsSensor, self).__init__(*args, **kwargs) 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
[docs] @staticmethod def filter_for_filesize(result, size=None): """ 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 = LoggingMixin().log 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
[docs] @staticmethod def filter_for_ignored_ext(result, ignored_ext, ignore_copying): """ 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: (bool) shall we ignore ? :return: (list) of dicts which were not removed """ if ignore_copying: log = LoggingMixin().log regex_builder = "^.*\.(%s$)$" % '$|'.join(ignored_ext) ignored_extentions_regex = re.compile(regex_builder) log.debug( 'Filtering result for ignored extensions: %s in files %s', ignored_extentions_regex.pattern, map(lambda x: x['path'], result) ) result = [x for x in result if not ignored_extentions_regex.match(x['path'])] log.debug('HdfsSensor.poke: after ext filter result is %s', result) return result
[docs] def poke(self, context): sb = self.hook(self.hdfs_conn_id).get_conn()'Poking for file {self.filepath}'.format(**locals())) try: # IMOO it's not right here, as there 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 does not raise any error # here is a quick fix result = [f for f in[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