Question

通用问题

我的python Cloud Function每秒引发约0.05个内存错误-每秒被调用约150次。我感到我的函数留下了内存残差，一旦它们处理了许多请求，就会导致其实例崩溃。您应该做什么或不应该做什么，以使函数实例在每次调用时都不会“占用更多的分配内存”？我已指向文档学习I should delete all temporary files，因为这是在内存中写的，但我认为我没有写任何东西。

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请求中包含有助于在电子商务网站上实施跟踪的参数。现在，我复制了它，可能会有一个反模式，当我在其上进行迭代时修改form['products']，但是我认为它与内存浪费没有关系吗？

from json import dumps
from datetime import datetime
from pytz import timezone

from google.cloud import storage
from google.cloud import pubsub
from google.cloud import error_reporting

from unidecode import unidecode

# this is done in global context because I only want to load the BOTS_LIST at
# cold start
PROJECT_ID = '...'
TOPIC_NAME = '...'
BUCKET_NAME = '...'
BOTS_PATH = '.../bots.txt'
gcs_client = storage.Client()
cf_bucket = gcs_client.bucket(BUCKET_NAME)
bots_blob = cf_bucket.blob(BOTS_PATH)
BOTS_LIST = bots_blob.download_as_string().decode('utf-8').split('\r\n')
del cf_bucket
del gcs_client
del bots_blob

err_client = error_reporting.Client()


def detect_nb_products(parameters):
    '''
    Detects number of products in the fields of the request.
    '''
    # ...


def remove_accents(d):
    '''
    Takes a dictionary and recursively transforms its strings into ASCII
    encodable ones
    '''
    # ...


def safe_float_int(x):
    '''
    Custom converter to float / int
    '''
    # ...


def build_hit_id(d):
    '''concatenate specific parameters from a dictionary'''
    # ...


def cloud_function(request):
    """Actual Cloud Function"""
    try:
        time_received = datetime.now().timestamp()
        # filtering bots
        user_agent = request.headers.get('User-Agent')
        if all([bot not in user_agent for bot in BOTS_LIST]):
            form = request.form.to_dict()
            # setting the products field
            nb_prods = detect_nb_products(form.keys())
            if nb_prods:
                form['products'] = [{'product_name': form['product_name%d' % i],
                                     'product_price': form['product_price%d' % i],
                                     'product_id': form['product_id%d' % i],
                                     'product_quantity': form['product_quantity%d' % i]}
                                    for i in range(1, nb_prods + 1)]

            useful_fields = [] # list of keys I'll keep from the form
            unwanted = set(form.keys()) - set(useful_fields)
            for key in unwanted:
                del form[key]

            # float conversion
            if nb_prods:
                for prod in form['products']:
                    prod['product_price'] = safe_float_int(
                        prod['product_price'])

            # adding timestamp/hour/minute, user agent and date to the hit
            form['time'] = int(time_received)
            form['user_agent'] = user_agent
            dt = datetime.fromtimestamp(time_received)
            form['date'] = dt.strftime('%Y-%m-%d')

            remove_accents(form)

            friendly_names = {} # dict to translate the keys I originally
            # receive to human friendly ones
            new_form = {}
            for key in form.keys():
                if key in friendly_names.keys():
                    new_form[friendly_names[key]] = form[key]
                else:
                    new_form[key] = form[key]
            form = new_form
            del new_form

            # logging
            print(form)

            # setting up Pub/Sub
            publisher = pubsub.PublisherClient()
            topic_path = publisher.topic_path(PROJECT_ID, TOPIC_NAME)
            # sending
            hit_id = build_hit_id(form)
            message_future = publisher.publish(topic_path,
                                               dumps(form).encode('utf-8'),
                                               time=str(int(time_received * 1000)),
                                               hit_id=hit_id)
            print(message_future.result())

            return ('OK',
                    200,
                    {'Access-Control-Allow-Origin': '*'})
        else:
        # do nothing for bots
            return ('OK',
                    200,
                    {'Access-Control-Allow-Origin': '*'})
    except KeyError:
        err_client.report_exception()
        return ('err',
                200,
                {'Access-Control-Allow-Origin': '*'})

Answer 1

您可以尝试一些方法（理论上的答案，我还没有玩过CF）：

明确删除在bot处理路径上分配的临时变量，这些临时变量可能相互引用，从而防止内存垃圾收集器释放它们（请参见https://stackoverflow.com/a/33091796/4495081）：nb_prods ，unwanted，form，new_form，friendly_names。
如果unwanted始终相同，则改为全局。
删除form，然后再将其分配给new_form（保留旧的form对象）；同样，删除new_form实际上不会节省太多，因为该对象仍然被form引用。即更改：
```
    form = new_form
    del new_form
```
进入
```
    del form
    form = new_form
```
在发布主题之后并返回之前，显式调用内存垃圾收集器。我不确定这是否适用于CF或调用是否立即有效（例如，在GAE中不是，请参见When will memory get freed after completing the request on App Engine Backend Instances?）。这也可能会过大，并有可能损害CF的性能，请查看它是否/如何为您工作。
```
gc.collect()
```

为了避免内存泄漏，我应该在python Cloud Function中避免哪些事情？

通用问题

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1 个答案: