流式迭代器

调用时 GoogleAdsService.search_stream、 系统会返回流式响应迭代器。此迭代器应保留在 使用与 GoogleAdsService 客户端相同的作用域，以免 或分段故障。这是因为 gRPC Channel 对象 一旦打开的 GoogleAdsService 对象超出范围，系统就会执行垃圾回收。 如果 GoogleAdsService 对象在迭代时不再位于作用域内 search_stream 的结果时，Channel 对象可能已经 已销毁，导致在迭代器尝试检索 下一个值。

以下代码演示了流式迭代器的错误用法：

def stream_response(client, customer_id, query):
    return client.get_service("GoogleAdsService", version="v17").search_stream(customer_id, query=query)

def main(client, customer_id):
    query = "SELECT campaign.name FROM campaign LIMIT 10"
    response = stream_response(client, customer_id, query=query)
    # Access the iterator in a different scope from where the service object was created.
    try:
        for batch in response:
            # Iterate through response, expect undefined behavior.

在上面的代码中，GoogleAdsService 对象是在 访问迭代器时所在的作用域。因此，Channel 对象 在迭代器使用整个响应之前被销毁。

相反，流式迭代器应保持与 GoogleAdsService 客户端（只要正在使用它）：

def main(client, customer_id):
    ga_service = client.get_service("GoogleAdsService", version="v17")
    query = "SELECT campaign.name FROM campaign LIMIT 10"
    response = ga_service.search_stream(customer_id=customer_id, query=query)
    # Access the iterator in the same scope as where the service object was created.
    try:
        for batch in response:
            # Successfully iterate through response.