如何使用 aiobotocore 模拟 AWS S3

Question

我有一个项目使用 aiohttp 和 aiobotocore 来处理 AWS 中的资源。我正在尝试测试与 AWS S3 一起使用的 class，并且我正在使用 moto 来模拟 AWS。模拟适用于使用同步代码的示例（来自 moto 文档的示例）

import boto3
from moto import mock_s3


class MyModel(object):
    def __init__(self, name, value):
        self.name = name
        self.value = value

    def save(self):
        s3 = boto3.client('s3', region_name='us-east-1')
        s3.put_object(Bucket='mybucket', Key=self.name, Body=self.value)


def test_my_model_save():
    with mock_s3():
        conn = boto3.resource('s3', region_name='us-east-1')
        conn.create_bucket(Bucket='mybucket')

        model_instance = MyModel('steve', 'is awesome')
        model_instance.save()
        body = conn.Object('mybucket', 'steve').get()['Body'].read().decode("utf-8")

        assert body == 'is awesome'

但是，在重写它以使用 aiobotocore 模拟之后不起作用 - 在我的示例中它连接到真实的 AWS S3。

import aiobotocore
import asyncio

import boto3
from moto import mock_s3


class MyModel(object):
    def __init__(self, name, value):
        self.name = name
        self.value = value

    async def save(self, loop):
        session = aiobotocore.get_session(loop=loop)
        s3 = session.create_client('s3', region_name='us-east-1')
        await s3.put_object(Bucket='mybucket', Key=self.name, Body=self.value)


def test_my_model_save():
    with mock_s3():
        conn = boto3.resource('s3', region_name='us-east-1')
        conn.create_bucket(Bucket='mybucket')
        loop = asyncio.get_event_loop()

        model_instance = MyModel('steve', 'is awesome')
        loop.run_until_complete(model_instance.save(loop=loop))
        body = conn.Object('mybucket', 'steve').get()['Body'].read().decode("utf-8")

        assert body == 'is awesome'

所以我在这里的假设是 moto 不能与 aiobotocore 一起正常工作。如果我的源代码类似于第二个示例，我如何才能有效地模拟 AWS 资源？

Answer 1

来自 moto 的模拟不起作用，因为它们使用同步 API。但是，您可以启动 moto 服务器并配置 aiobotocore 以连接到此测试服务器。 Take a look on aiobotocore tests 寻找灵感。

Answer 2

这是来自 aiobotocore 的 mock_server.py，没有 pytest：

# Initially from https://raw.githubusercontent.com/aio-libs/aiobotocore/master/tests/mock_server.py

import shutil
import signal
import subprocess as sp
import sys
import time
import requests


_proxy_bypass = {
  "http": None,
  "https": None,
}


def start_service(service_name, host, port):
    moto_svr_path = shutil.which("moto_server")
    args = [sys.executable, moto_svr_path, service_name, "-H", host,
            "-p", str(port)]
    process = sp.Popen(args, stdin=sp.PIPE, stdout=sp.PIPE, stderr=sp.DEVNULL)
    url = "http://{host}:{port}".format(host=host, port=port)

    for _ in range(30):
        if process.poll() is not None:
            break

        try:
            # we need to bypass the proxies due to monkeypatches
            requests.get(url, timeout=0.1, proxies=_proxy_bypass)
            break
        except requests.exceptions.RequestException:
            time.sleep(0.1)
    else:
        stop_process(process)
        raise AssertionError("Can not start service: {}".format(service_name))

    return process


def stop_process(process, timeout=20):
    try:
        process.send_signal(signal.SIGTERM)
        process.communicate(timeout=timeout / 2)
    except sp.TimeoutExpired:
        process.kill()
        outs, errors = process.communicate(timeout=timeout / 2)
        exit_code = process.returncode
        msg = "Child process finished {} not in clean way: {} {}" \
            .format(exit_code, outs, errors)
        raise RuntimeError(msg)

Answer 3

使用 AWS 的 stubber 应该可以解决问题。以下是我在 tornado 应用程序中执行 aws 读取操作的方法：

import aiobotocore
from botocore.stub import Stubber
from tornado.testing import AsyncTestCase
from aiobotocore.response import StreamingBody


class RawStream(io.BytesIO):

    async def __aenter__(self):
        return self

    async def __aexit__(self, exc_type, exc_val, exc_tb):
        pass

    async def read(self, n):
        return super().read(n)

class S3TestCase(AsyncTestCase):

    def setUp(self):
        super().setUp()
        session = aiobotocore.get_session()
        self.client = session.create_client("s3", region_name="AWS_S3_REGION",
                                    aws_secret_access_key="AWS_SECRET_ACCESS_KEY",
                                    aws_access_key_id="AWS_ACCESS_KEY_ID")

    @tornado.testing.gen_test
    def test_read(self):
        stubber = Stubber(self.client)
        stubber.add_response("get_object",
                          {"Body": StreamingBody(raw_stream=RawStream(self.binary_content), content_length=128),
                          "ContentLength": 128},
                         expected_params={"Bucket": "AWS_S3_BUCKET",
                                          "Key": "filename"})
        stubber.activate()

        response = await client.get_object(Bucket="AWS_S3_BUCKET", Key="filename")

写入操作应该类似。希望这会引导您朝着正确的方向前进。

有关 stubber 的更多信息：https://botocore.amazonaws.com/v1/documentation/api/latest/reference/stubber.html

Answer 4

我认为 Sebastian Brestins 的回答应该被接受。我要 post 这个新答案，因为自 posted 以来有些事情发生了变化，例如python 3.8 现在支持异步测试用例，aioboto3 客户端现在是上下文管理器。

使用 python 3.8 的最小示例如下所示：

from unittest import IsolatedAsyncioTestCase

import aioboto3
from botocore.stub import Stubber

class Test(IsolatedAsyncioTestCase):

    async def asyncSetUp(self):
        self._s3_client = await aioboto3.client('s3').__aenter__()
        self._s3_stub = Stubber(self._s3_client)

    async def asyncTearDown(self):
        await self._s3_client.__aexit__(None, None, None)

    async def test_case(self):
        self._s3_stub.add_response(
            "get_object",
            {"Body": "content"},
            expected_params={"Bucket": "AWS_S3_BUCKET", "Key": "filename"}
        )
        self._s3_stub.activate()

        response = await self._s3_client.get_object(Bucket="AWS_S3_BUCKET", Key="filename")

        self.assertEquals(response, "content")

Answer 5

我们可以使用 moto[server] 创建 S3 服务器，然后从中创建一个类似于 aioboto3

的 pytest fixture

@pytest.yield_fixture(scope='session')
def s3_server():
    host = 'localhost'
    port = 5002
    url = 'http://{host}:{port}'.format(host=host, port=port)
    process = start_service('s3', host, port)
    yield url
    stop_process(process)

然后 patch('aiobotocore.AioSession.create_client') return_value 和 aiobotocore.get_session().create_client('s3', region_name='us-east-1', end_point_url=s3_server) 如下

async with aiobotocore.get_session().create_client('s3', region_name='us-east-1', end_point_url=s3_server) as client:
    with patch('aiobotocore.AioSession.create_client') as mock:
        mock.return_value = client
        # Test your code

Answer 6

不幸的是，这不是一个完整的答案，但有一个添加此功能的拉取请求已经开放了 6 个月：https://github.com/aio-libs/aiobotocore/pull/766

当我处理 asyncio 的类似问题时，我为同步对象手动编写了“异步”包装器。

如何使用 aiobotocore 模拟 AWS S3

How to mock AWS S3 with aiobotocore

python

aiohttp

moto