Python urllib.请求和url库.错误的使用

Question

我有一小部分使用urllib的Python代码。请求和url库。错误检查URL的状态。如果出现错误，这将触发SNS发布到主题。

import boto3
from urllib.request import urlopen
from urllib.error import HTTPError
from os import environ
region = 'eu-west-2'
def get_status_code(url, topic):
try:
connection = urlopen(url, timeout=10)
status = connection.getcode()
print('%s Status is %s' % (url, status))
connection.close()
except HTTPError as err:
status = err.getcode()
print('%s: Status is unreachable - %s' % (url, status))
sns_client = boto3.client('sns', region_name=region)
message = sns_client.publish(TopicArn=topic,
Message='%s is unreachable - HTTP error code is: %s' % (url, status)
)
print("Publish to SNS, Lambda update triggered: {}".format(message))
def lambda_handler(event, context):
dns = environ['dns']
sns_topic = environ['sns_topic_arn']
get_status_code(dns, sns_topic)

作为测试的一部分，我经历了不同程度的成功。如果我将超时保持在urloopen中，它将无法触发except处理程序，但会转储一个失败。如果设置超时限制，它被认为是一个错误，那么为什么它不触发异常处理程序?

timed out: timeout
Traceback (most recent call last):
File "/var/task/lambda_function1.py", line 27, in lambda_handler
get_status_code(elb_dns, sns_topic)
File "/var/task/lambda_function1.py", line 10, in get_status_code
connection = urlopen(url, timeout=10)
File "/var/lang/lib/python3.6/urllib/request.py", line 223, in urlopen
return opener.open(url, data, timeout)
File "/var/lang/lib/python3.6/urllib/request.py", line 526, in open
response = self._open(req, data)
File "/var/lang/lib/python3.6/urllib/request.py", line 544, in _open
'_open', req)
File "/var/lang/lib/python3.6/urllib/request.py", line 504, in _call_chain
result = func(*args)
File "/var/lang/lib/python3.6/urllib/request.py", line 1377, in http_open
return self.do_open(http.client.HTTPConnection, req)
File "/var/lang/lib/python3.6/urllib/request.py", line 1352, in do_open
r = h.getresponse()
File "/var/lang/lib/python3.6/http/client.py", line 1379, in getresponse
response.begin()
File "/var/lang/lib/python3.6/http/client.py", line 311, in begin
version, status, reason = self._read_status()
File "/var/lang/lib/python3.6/http/client.py", line 272, in _read_status
line = str(self.fp.readline(_MAXLINE + 1), "iso-8859-1")
File "/var/lang/lib/python3.6/socket.py", line 586, in readinto
return self._sock.recv_into(b)
socket.timeout: timed out

如果我从uropen中删除超时，作业超时后3分钟并触发except处理程序，然后成功完成(我知道如果它在10s后没有工作，它不会)。

如果我使用HTTPS URL，也会出现第二个意外错误。它也无法触发异常处理程序。

<urlopen error timed out>: URLError
Traceback (most recent call last):
File "/var/task/lambda_function1.py", line 24, in lambda_handler
get_status_code(elb_dns, sns_topic)
File "/var/task/lambda_function1.py", line 8, in get_status_code
connection = urlopen(url, timeout=10)
File "/var/lang/lib/python3.6/urllib/request.py", line 223, in urlopen
return opener.open(url, data, timeout)
File "/var/lang/lib/python3.6/urllib/request.py", line 526, in open
response = self._open(req, data)
File "/var/lang/lib/python3.6/urllib/request.py", line 544, in _open
'_open', req)
File "/var/lang/lib/python3.6/urllib/request.py", line 504, in _call_chain
result = func(*args)
File "/var/lang/lib/python3.6/urllib/request.py", line 1392, in https_open
context=self._context, check_hostname=self._check_hostname)
File "/var/lang/lib/python3.6/urllib/request.py", line 1351, in do_open
raise URLError(err)
urllib.error.URLError: <urlopen error timed out>

Answer 1

因此，当我添加输出的错误时，我注意到它们没有写入HTTPError(我期望超时至少如果默认超时???)异常处理程序期望:

import boto3
import socket
from socket import AF_INET, SOCK_DGRAM
from urllib.request import urlopen
from urllib.error import HTTPError
from urllib.error import URLError
from os import environ
region = 'eu-west-2'
def get_status_code(url, topic):
try:
connection = urlopen(url, timeout=10)
status = connection.getcode()
print('%s Status is %s' % (url, status))
connection.close()
except (socket.timeout, URLError, HTTPError) as err:
status = err
print('%s: Status is unreachable - %s' % (url, status))
sns_client = boto3.client('sns', region_name=region)
message = sns_client.publish(TopicArn=topic,
Message='%s is unreachable - HTTP error code is: %s' % (url, status)
)
print("Publish to SNS, Lambda update triggered: {}".format(message))
def lambda_handler(event, context):
dns = environ['dns']
sns_topic = environ['sns_topic_arn']
get_status_code(dns, sns_topic)

所以我将新的错误添加到异常处理程序中，现在它们正在被捕获和处理。它打破了我的HTTP错误码是因为我现在只是得到错误信息，但它比以前工作得更好。