优雅地捕获Iterator中的python异常

Question

我正在使用PyGithub来抓取一些存储库，尽管我在迭代搜索页面时遇到了一些错误。

def scrape_interval(self, interval):
    for repo_number, repo in self.search(interval):
        code...

def search(self, interval):
    try:
        iterator = enumerate(self.github.search_repositories(query="Laravel created:" + interval))
    except:
        print.warning("Going to sleep for 1 hour. The search API hit the limit")
        time.sleep(3600)
        iterator = self.search(interval)
    return iterator

如您所见，在def search中创建迭代器时，我尝试捕捉错误。但是这个错误是在for repo_number, repo in self.search(interval):上抛出的，所以在迭代器得到下一个项目的某个时候？

我有什么选择来使这些错误容易被发现？我最好避免将整个for循环包装在try子句中，而不是在迭代过程中管理它。

有关错误本身的参考：

File "/Users/olofjondelius/Documents/Code/laravel-ai/src/examples/migration-analysis/../../GithubScraper.py", line 47, in scrape_interval
    for repo_number, repo in self.search(interval):
  File "/anaconda3/envs/laravel-ai/lib/python3.7/site-packages/github/PaginatedList.py", line 58, in _iter_
    newElements = self._grow()
  File "/anaconda3/envs/laravel-ai/lib/python3.7/site-packages/github/PaginatedList.py", line 70, in _grow
    newElements = self._fetchNextPage()
  File "/anaconda3/envs/laravel-ai/lib/python3.7/site-packages/github/PaginatedList.py", line 172, in _fetchNextPage
    headers=self.__headers
  File "/anaconda3/envs/laravel-ai/lib/python3.7/site-packages/github/Requester.py", line 185, in requestJsonAndCheck
    return self.__check(*self.requestJson(verb, url, parameters, headers, input, cnx))
  File "/anaconda3/envs/laravel-ai/lib/python3.7/site-packages/github/Requester.py", line 231, in requestJson
    return self.__requestEncode(cnx, verb, url, parameters, headers, input, encode)
  File "/anaconda3/envs/laravel-ai/lib/python3.7/site-packages/github/Requester.py", line 284, in __requestEncode
    status, responseHeaders, output = self.__requestRaw(cnx, verb, url, requestHeaders, encoded_input)
  File "/anaconda3/envs/laravel-ai/lib/python3.7/site-packages/github/Requester.py", line 309, in __requestRaw
    requestHeaders
  File "/anaconda3/envs/laravel-ai/lib/python3.7/http/client.py", line 1229, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/anaconda3/envs/laravel-ai/lib/python3.7/http/client.py", line 1275, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/anaconda3/envs/laravel-ai/lib/python3.7/http/client.py", line 1224, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/anaconda3/envs/laravel-ai/lib/python3.7/http/client.py", line 1016, in _send_output
    self.send(msg)
  File "/anaconda3/envs/laravel-ai/lib/python3.7/http/client.py", line 956, in send
    self.connect()
  File "/anaconda3/envs/laravel-ai/lib/python3.7/http/client.py", line 1384, in connect
    super().connect()
  File "/anaconda3/envs/laravel-ai/lib/python3.7/http/client.py", line 928, in connect
    (self.host,self.port), self.timeout, self.source_address)
  File "/anaconda3/envs/laravel-ai/lib/python3.7/socket.py", line 707, in create_connection
    for res in getaddrinfo(host, port, 0, SOCK_STREAM):
  File "/anaconda3/envs/laravel-ai/lib/python3.7/socket.py", line 748, in getaddrinfo
    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno 8] nodename nor servname provided, or not known

Answer 1

听起来，当您在迭代器上迭代时，而不是在创建迭代器时，会引发异常。当前的try和except块只捕获在调用self.github.search_repositories时立即引发的异常，而不是在使用结果时出现的异常。

要解决这个问题，您可以让search函数成为一个生成器。这将使您在有值的情况下产生值，但仍然会捕获异常，并根据需要经常重试。

试着做这样的事情：

def search(self, interval):
    while True:
        try:
            it = enumerate(self.github.search_repositories(query="Laravel created:" + interval))
            yield from it
            return   # if we completed the yield from without an exception, we're done!

        except:  # you should probably limit this to catching a specific exception types
            print.warning("Going to sleep for 1 hour. The search API hit the limit")
            time.sleep(3600)

正如我在一条注释中指出的，您可能应该将裸except语句更改为except socket.gaierror或类似的东西，这样就不会抑制所有异常，而是只会阻止所期望的异常，并且延迟将为您修复。仍然应该允许一些真正出乎意料的东西停止程序(因为它可能反映在代码的其他地方)。