捕获在greenlet中引发的异常

Question

我正在尝试捕获在greenlet中引发的异常。根据this tutorial的说法，不幸的是‘Greenlet中引发的异常，留在Greenlet内部’。在下面的代码中，我使用了一个sync方法来生成爬虫greenlet。这些爬行的greenlet会引发HTTPError异常，我需要在sync方法的主体中捕获它。基于异常，在sync方法中，我将设置Account对象的适当状态。您知道如何在sync方法中捕获在greenlet中引发的异常以实现此目的吗？提前谢谢你！

# this is standalone helper method
def crawl(item):
    try:
        item.refresh_children(False) # THROWS HTTPError exception
        greenlets = [gevent.spawn_link_exception(crawl, child) for child in item.children]
        gevent.joinall(greenlets)
    except HTTPError, e:
        print e.message
        raise e
    except (JSONDecodeError, InvalidCredentialsException) as e:
        print e.message
        raise e

# this is instance method of the Account class 
def sync(self):
    "Sync search index with data from source"
    try:
        greenlets = [gevent.spawn_link_exception(crawl, item) for item in self.get_navigation()]
        gevent.joinall(greenlets)
        self.date_synced = datetime.datetime.now()
        self.save()
    except HTTPError, e:
        if e.status_code == 401:
            self.status = 'revoked'
        else:
            self.status = 'error'
        self.save()
    except LinkedFailed, e:
        print e.message
        exception_name = e.message.split()[-1]
        if exception_name in ['HTTPError', 'JSONDecodeError']:
            self.status = 'error'
            self.save()
        elif exception_name == 'InvalidCredentialsException':
            self.status = 'revoked'
            self.save()

Answer 1

greenlet将保存为greenlet或异常产生的函数的结果(如果引发了一个异常)。您可以使用get方法获取结果或重新引发异常。由于您似乎要基于任何greenlet更改状态，因此出错的sync方法最终将如下所示：

def sync(self):
    "Sync search index with data from source"
    greenlets = [gevent.spawn_link_exception(crawl, item) for item in self.get_navigation()]
    gevent.joinall(greenlets)
    try:
        results = [greenlet.get() for greenlet in greenlets]
    except HTTPError, e:
        if e.status_code == 401:
            self.status = 'revoked'
        else:
            self.status = 'error'
        self.save()
    except LinkedFailed, e:
        print e.message
        exception_name = e.message.split()[-1]
        if exception_name in ['HTTPError', 'JSONDecodeError']:
            self.status = 'error'
            self.save()
        elif exception_name == 'InvalidCredentialsException':
            self.status = 'revoked'
            self.save()

    self.date_synced = datetime.datetime.now()
    self.save()