cachier/tests/test_mongo_core.py

"""Testing the MongoDB core of cachier."""

from __future__ import print_function
import sys
import datetime
from datetime import timedelta
from random import random
from time import sleep
import threading
try:
    import queue
except ImportError:  # python 2
    import Queue as queue

import pytest
import pymongo
from pymongo.mongo_client import MongoClient
from pymongo.errors import OperationFailure

from cachier import cachier
from cachier.mongo_core import _MongoCore, RecalculationNeeded

_TEST_HOST = 'ds119508.mlab.com'
_TEST_PORT = 19508
_TEST_USERNAME = 'cachier_test'
_TEST_PWD = 'ZGhjO5CQESYJ69U4z65G79YG'


def _get_cachier_db_mongo_client():
    client = MongoClient(host=_TEST_HOST, port=_TEST_PORT, retryWrites=False)
    client.cachier_test.authenticate(
        name=_TEST_USERNAME,
        password=_TEST_PWD,
        mechanism='SCRAM-SHA-1'
    )
    return client


_COLLECTION_NAME = 'cachier_test{}.{}.{}'.format(
    sys.version_info[0], sys.version_info[1], sys.version_info[2])


def _test_mongetter():
    if not hasattr(_test_mongetter, 'client'):
        _test_mongetter.client = _get_cachier_db_mongo_client()
    db_obj = _test_mongetter.client['cachier_test']
    if _COLLECTION_NAME not in db_obj.list_collection_names():
        db_obj.create_collection(_COLLECTION_NAME)
    return db_obj[_COLLECTION_NAME]


# === Mongo core tests ===


def test_information():
    print("\npymongo version: ", end="")
    print(pymongo.__version__)


@cachier(mongetter=_test_mongetter)
def _test_mongo_caching(arg_1, arg_2):
    """Some function."""
    return random() + arg_1 + arg_2


def test_mongo_index_creation():
    """Basic Mongo core functionality."""
    collection = _test_mongetter()
    _test_mongo_caching.clear_cache()
    val1 = _test_mongo_caching(1, 2)
    val2 = _test_mongo_caching(1, 2)
    assert val1 == val2
    assert _MongoCore._INDEX_NAME in collection.index_information()


def test_mongo_core():
    """Basic Mongo core functionality."""
    _test_mongo_caching.clear_cache()
    val1 = _test_mongo_caching(1, 2)
    val2 = _test_mongo_caching(1, 2)
    assert val1 == val2
    val3 = _test_mongo_caching(1, 2, ignore_cache=True)
    assert val3 != val1
    val4 = _test_mongo_caching(1, 2)
    assert val4 == val1
    val5 = _test_mongo_caching(1, 2, overwrite_cache=True)
    assert val5 != val1
    val6 = _test_mongo_caching(1, 2)
    assert val6 == val5


MONGO_DELTA = timedelta(seconds=3)


@cachier(mongetter=_test_mongetter, stale_after=MONGO_DELTA, next_time=False)
def _stale_after_mongo(arg_1, arg_2):
    """Some function."""
    return random() + arg_1 + arg_2


def test_mongo_stale_after():
    """Testing MongoDB core stale_after functionality."""
    _stale_after_mongo.clear_cache()
    val1 = _stale_after_mongo(1, 2)
    val2 = _stale_after_mongo(1, 2)
    assert val1 == val2
    sleep(3)
    val3 = _stale_after_mongo(1, 2)
    assert val3 != val1


@cachier(mongetter=_test_mongetter)
def _takes_time(arg_1, arg_2):
    """Some function."""
    sleep(3)
    return random() + arg_1 + arg_2


def _calls_takes_time(res_queue):
    res = _takes_time(34, 82.3)
    res_queue.put(res)


def test_mongo_being_calculated():
    """Testing MongoDB core handling of being calculated scenarios."""
    _takes_time.clear_cache()
    res_queue = queue.Queue()
    thread1 = threading.Thread(
        target=_calls_takes_time, kwargs={'res_queue': res_queue})
    thread2 = threading.Thread(
        target=_calls_takes_time, kwargs={'res_queue': res_queue})
    thread1.start()
    sleep(1)
    thread2.start()
    thread1.join()
    thread2.join()
    assert res_queue.qsize() == 2
    res1 = res_queue.get()
    res2 = res_queue.get()
    assert res1 == res2


class _BadMongoCollection:

    def __init__(self, mongetter):
        self.collection = mongetter()
        self.index_information = self.collection.index_information
        self.create_indexes = self.collection.create_indexes
        self.find_one = self.collection.find_one

    def delete_many(self, *args, **kwargs):  # skipcq: PYL-R0201, PYL-W0613
        pass

    def update_many(self, *args, **kwargs):  # skipcq: PYL-R0201, PYL-W0613

        pass

    def update_one(self, *args, **kwargs):  # skipcq: PYL-R0201, PYL-W0613
        raise OperationFailure(Exception())


def _bad_mongetter():
    return _BadMongoCollection(_test_mongetter)


@cachier(mongetter=_bad_mongetter)
def _func_w_bad_mongo(arg_1, arg_2):
    """Some function."""
    return random() + arg_1 + arg_2


def test_mongo_write_failure():
    """Testing MongoDB core handling of writing failure scenarios."""
    with pytest.raises(OperationFailure):
        val1 = _func_w_bad_mongo(1, 2)
        val2 = _func_w_bad_mongo(1, 2)
        assert val1 == val2


def test_mongo_clear_being_calculated():
    """Testing MongoDB core clear_being_calculated."""
    _func_w_bad_mongo.clear_being_calculated()


def test_stalled_mongo_db_cache():
    @cachier(mongetter=_test_mongetter)
    def _stalled_func():
        return 1
    core = _MongoCore(_test_mongetter, None, False)
    core.set_func(_stalled_func)
    core.clear_cache()
    with pytest.raises(RecalculationNeeded):
        core.wait_on_entry_calc(key=None)


def test_stalled_mong_db_core(monkeypatch):

    def mock_get_entry(self, args, kwargs):  # skipcq: PYL-R0201, PYL-W0613
        return "key", {'being_calculated': True}

    def mock_get_entry_by_key(self, key):  # skipcq: PYL-R0201, PYL-W0613
        return "key", None

    monkeypatch.setattr(
        "cachier.mongo_core._MongoCore.get_entry", mock_get_entry)
    monkeypatch.setattr(
        "cachier.mongo_core._MongoCore.get_entry_by_key", mock_get_entry_by_key
    )

    @cachier(mongetter=_test_mongetter)
    def _stalled_func():
        return 1
    res = _stalled_func()
    assert res == 1

    def mock_get_entry_2(self, args, kwargs):  # skipcq: PYL-W0613
        entry = {
            'being_calculated': True,
            "value": 1,
            "time": datetime.datetime.now() - datetime.timedelta(seconds=10)
        }
        return "key", entry

    monkeypatch.setattr(
        "cachier.mongo_core._MongoCore.get_entry", mock_get_entry_2)

    stale_after = datetime.timedelta(seconds=1)

    @cachier(mongetter=_test_mongetter, stale_after=stale_after)
    def _stalled_func_2():
        """Testing stalled function"""
        return 2

    res = _stalled_func_2()
    assert res == 2