#
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information 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
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""Utilities for testing Beam pipelines."""
from __future__ import absolute_import
import collections
import glob
import io
import tempfile
from builtins import object
from apache_beam import pvalue
from apache_beam.transforms import window
from apache_beam.transforms.core import Create
from apache_beam.transforms.core import DoFn
from apache_beam.transforms.core import Map
from apache_beam.transforms.core import ParDo
from apache_beam.transforms.core import WindowInto
from apache_beam.transforms.ptransform import PTransform
from apache_beam.transforms.util import CoGroupByKey
from apache_beam.utils.annotations import experimental
__all__ = [
'assert_that',
'equal_to',
'is_empty',
'is_not_empty',
'matches_all',
# open_shards is internal and has no backwards compatibility guarantees.
'open_shards',
'TestWindowedValue',
]
class BeamAssertException(Exception):
"""Exception raised by matcher classes used by assert_that transform."""
pass
# Used for reifying timestamps and windows for assert_that matchers.
TestWindowedValue = collections.namedtuple(
'TestWindowedValue', 'value timestamp windows')
def contains_in_any_order(iterable):
"""Creates an object that matches another iterable if they both have the
same count of items.
Arguments:
iterable: An iterable of hashable objects.
"""
class InAnyOrder(object):
def __init__(self, iterable):
self._counter = collections.Counter(iterable)
def __eq__(self, other):
return self._counter == collections.Counter(other)
def __ne__(self, other):
# TODO(BEAM-5949): Needed for Python 2 compatibility.
return not self == other
def __hash__(self):
return hash(self._counter)
def __repr__(self):
return "InAnyOrder(%s)" % self._counter
return InAnyOrder(iterable)
def equal_to_per_window(expected_window_to_elements):
"""Matcher used by assert_that to check on values for specific windows.
Arguments:
expected_window_to_elements: A dictionary where the keys are the windows
to check and the values are the elements associated with each window.
"""
def matcher(elements):
actual_elements_in_window, window = elements
if window in expected_window_to_elements:
expected_elements_in_window = list(
expected_window_to_elements[window])
sorted_expected = sorted(expected_elements_in_window)
sorted_actual = sorted(actual_elements_in_window)
if sorted_expected != sorted_actual:
# Results for the same window don't necessarily come all
# at once. Hence the same actual window may contain only
# subsets of the expected elements for the window.
# For example, in the presence of early triggers.
if all(elem in sorted_expected for elem in sorted_actual) is False:
raise BeamAssertException(
'Failed assert: %r not in %r' % (sorted_actual, sorted_expected))
return matcher
# Note that equal_to checks if expected and actual are permutations of each
# other. However, only permutations of the top level are checked. Therefore
# [1,2] and [2,1] are considered equal and [[1,2]] and [[2,1]] are not.
[docs]def equal_to(expected):
def _equal(actual):
expected_list = list(expected)
# Try to compare actual and expected by sorting. This fails with a
# TypeError in Python 3 if different types are present in the same
# collection. It can also raise false negatives for types that don't have
# a deterministic sort order, like pyarrow Tables as of 0.14.1
try:
sorted_expected = sorted(expected)
sorted_actual = sorted(actual)
if sorted_expected != sorted_actual:
raise BeamAssertException(
'Failed assert: %r == %r' % (sorted_expected, sorted_actual))
# Slower method, used in two cases:
# 1) If sorted expected != actual, use this method to verify the inequality.
# This ensures we don't raise any false negatives for types that don't
# have a deterministic sort order.
# 2) As a fallback if we encounter a TypeError in python 3. this method
# works on collections that have different types.
except (BeamAssertException, TypeError):
for element in actual:
try:
expected_list.remove(element)
except ValueError:
raise BeamAssertException(
'Failed assert: %r == %r' % (expected, actual))
if expected_list:
raise BeamAssertException(
'Failed assert: %r == %r' % (expected, actual))
return _equal
[docs]def matches_all(expected):
"""Matcher used by assert_that to check a set of matchers.
Args:
expected: A list of elements or hamcrest matchers to be used to match
the elements of a single PCollection.
"""
def _matches(actual):
from hamcrest.core import assert_that as hamcrest_assert
from hamcrest.library.collection import contains_inanyorder
expected_list = list(expected)
hamcrest_assert(actual, contains_inanyorder(*expected_list))
return _matches
[docs]def is_empty():
def _empty(actual):
actual = list(actual)
if actual:
raise BeamAssertException(
'Failed assert: [] == %r' % actual)
return _empty
[docs]def is_not_empty():
"""
This is test method which makes sure that the pcol is not empty and it has
some data in it.
:return:
"""
def _not_empty(actual):
actual = list(actual)
if not actual:
raise BeamAssertException('Failed assert: pcol is empty')
return _not_empty
[docs]def assert_that(actual, matcher, label='assert_that',
reify_windows=False, use_global_window=True):
"""A PTransform that checks a PCollection has an expected value.
Note that assert_that should be used only for testing pipelines since the
check relies on materializing the entire PCollection being checked.
Args:
actual: A PCollection.
matcher: A matcher function taking as argument the actual value of a
materialized PCollection. The matcher validates this actual value against
expectations and raises BeamAssertException if they are not met.
label: Optional string label. This is needed in case several assert_that
transforms are introduced in the same pipeline.
reify_windows: If True, matcher is passed a list of TestWindowedValue.
use_global_window: If False, matcher is passed a dictionary of
(k, v) = (window, elements in the window).
Returns:
Ignored.
"""
assert isinstance(actual, pvalue.PCollection)
class ReifyTimestampWindow(DoFn):
def process(self, element, timestamp=DoFn.TimestampParam,
window=DoFn.WindowParam):
# This returns TestWindowedValue instead of
# beam.utils.windowed_value.WindowedValue because ParDo will extract
# the timestamp and window out of the latter.
return [TestWindowedValue(element, timestamp, [window])]
class AddWindow(DoFn):
def process(self, element, window=DoFn.WindowParam):
yield element, window
class AssertThat(PTransform):
def expand(self, pcoll):
if reify_windows:
pcoll = pcoll | ParDo(ReifyTimestampWindow())
keyed_singleton = pcoll.pipeline | Create([(None, None)])
if use_global_window:
pcoll = pcoll | WindowInto(window.GlobalWindows())
keyed_actual = pcoll | "ToVoidKey" >> Map(lambda v: (None, v))
plain_actual = ((keyed_singleton, keyed_actual)
| "Group" >> CoGroupByKey()
| "Unkey" >> Map(lambda k_values: k_values[1][1]))
if not use_global_window:
plain_actual = plain_actual | "AddWindow" >> ParDo(AddWindow())
plain_actual = plain_actual | "Match" >> Map(matcher)
def default_label(self):
return label
actual | AssertThat() # pylint: disable=expression-not-assigned
[docs]@experimental()
def open_shards(glob_pattern, mode='rt', encoding='utf-8'):
"""Returns a composite file of all shards matching the given glob pattern.
Args:
glob_pattern (str): Pattern used to match files which should be opened.
mode (str): Specify the mode in which the file should be opened. For
available modes, check io.open() documentation.
encoding (str): Name of the encoding used to decode or encode the file.
This should only be used in text mode.
Returns:
A stream with the contents of the opened files.
"""
if 'b' in mode:
encoding = None
with tempfile.NamedTemporaryFile(delete=False) as out_file:
for shard in glob.glob(glob_pattern):
with open(shard, 'rb') as in_file:
out_file.write(in_file.read())
concatenated_file_name = out_file.name
return io.open(concatenated_file_name, mode, encoding=encoding)