# -*- coding: utf-8 -*-
#
# Licensed to the Apache Software Foundation (ASF) under one
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# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
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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()
self.log.info('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 sb.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