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How to change Prometheus error message if token is invalid?

I have a python file called main.py and I am trying to make a Prometheus connection with a specific token. However, if the token is expired, instead of the error message printing out prometheus_api_client.exceptions.PrometheusApiClientException, how can I get the error message to print our like status_code: 500, reason: Invalid token using a try and except block.
Code:
#token="V0aksn-as9ckcnblqc6bi3ans9cj1nsk" #example, expired token
token ="c0ams7bnskd9dk1ndk7aKNYTVOVRBajs" #example, valid token
pc = PrometheusConnect(url = url, headers={"Authorization": "bearer {}".format(token)}, disable_ssl=True)
try:
#Not entirely sure what to put here and the except block
except:
I've tested out a couple code in the try and except blocks and could not get rid of the long error from Prometheus. Any suggestions?

How about putting your pc variable in try and PrometheusApiClientException for the exception. If that doesn't work, go to the source file and use whatever exception developers used while making authorization.

This is how you catch that exception in a try/except block
try:
# Interact with prometheus here
pass
except prometheus_api_client.exceptions.PrometheusApiClientException as e:
print('status_code: 500, reason: Invalid token')

Handling exception in calling a external api

I'm calling Udemy external api to build a simple REST service for experimental purpose.
https://www.udemy.com/developers/affiliate/
Here is my get_all() courses method.
class Courses(object):
"""
Handles all requests related to courses.
ie; gets the courses-list, courses-detail, coursesreviews-list
"""
def __init__(self, api):
self.api = api
logger.debug("courses initialized")
def get_all(self):
page = 1
per_page = 20
while True:
res = self._get_courses(page, per_page)
if not res['results']:
break
try:
for one in res['results']:
yield one
except Exception as e: -->>>handling exception
print(e)
break
page += 1
def _get_courses_detail(self, page, per_page):
resource = "courses"
params = {'page': page, 'per_page': per_page,
# 'fields[course]': '#all'
}
res = self.api.get(resource, params)
return res
Now, is it reasonable to handle a exception(in get_all() method) assuming that there could some error in the returning data of the api?
Or handling the exception(in get_all) is not needed here and it should be handled by the calling function?
Most of the open source projects that I see don't handle this exception.

I'm sharing the opinion in this answer. So catch the exception as soon as possible and rethrow it if needed to the next layer.
With practice and experience with your code base it becomes quite easy to judge when to add additional context to errors, and where it's most sensible to actually, finally handle the errors.
Catch → Rethrow
Do this where you can usefully add more information that would save a developer having to work through all the layers to understand the problem.
Catch → Handle
Do this where you can make final decisions on what is an appropriate, but different execution flow through the software.
Catch → Error Return

urllib request fails when page takes too long to respond

I have a simple function (in python 3) to take a url and attempt to resolve it: printing an error code if there is one (e.g. 404) or resolve one of the shortened urls to its full url. My urls are in one column of a csv files and the output is saved in the next column. The problem arises where the program encounters a url where the server takes too long to respond- the program just crashes. Is there a simple way to force urllib to print an error code if the server is taking too long. I looked into Timeout on a function call but that looks a little too complicated as i am just starting out. Any suggestions?
i.e. (COL A) shorturl (COL B) http://deals.ebay.com/500276625
def urlparse(urlColumnElem):
try:
conn = urllib.request.urlopen(urlColumnElem)
except urllib.error.HTTPError as e:
return (e.code)
except urllib.error.URLError as e:
return ('URL_Error')
else:
redirect=conn.geturl()
#check redirect
if(redirect == urlColumnElem):
#print ("same: ")
#print(redirect)
return (redirect)
else:
#print("Not the same url ")
return(redirect)
EDIT: if anyone gets the http.client.disconnected error (like me), see this question/answer http.client.RemoteDisconnected error while reading/parsing a list of URL's

Have a look at the docs:
urllib.request.urlopen(url, data=None[, timeout])
The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used).
You can set a realistic timeout (in seconds) for your process:
conn = urllib.request.urlopen(urlColumnElem, timeout=realistic_timeout_in_seconds)
and in order for your code to stop crushing, move everything inside the try except block:
import socket
def urlparse(urlColumnElem):
try:
conn = urllib.request.urlopen(
urlColumnElem,
timeout=realistic_timeout_in_seconds
)
redirect=conn.geturl()
#check redirect
if(redirect == urlColumnElem):
#print ("same: ")
#print(redirect)
return (redirect)
else:
#print("Not the same url ")
return(redirect)
except urllib.error.HTTPError as e:
return (e.code)
except urllib.error.URLError as e:
return ('URL_Error')
except socket.timeout as e:
return ('Connection timeout')
Now if a timeout occurs, you will catch the exception and the program will not crush.
Good luck :)

First, there is a timeout parameter than can be used to control the time allowed for urlopen. Next an timeout in urlopen should just throw an exception, more precisely a socket.timeout. If you do not want it to abort the program, you just have to catch it:
def urlparse(urlColumnElem, timeout=5): # allow 5 seconds by default
try:
conn = urllib.request.urlopen(urlColumnElem, timeout = timeout)
except urllib.error.HTTPError as e:
return (e.code)
except urllib.error.URLError as e:
return ('URL_Error')
except socket.timeout:
return ('Timeout')
else:
...

tweepy/ twitter api error type

I am using tweepy to make a twitter application.
When users tweet/update profile, etc, they will get some errors. I want to classify error and give user more information.
try:
tweet/update profile/ follow....
except tweepy.TweepError, e:
if tweepy.TweepError is "Account update failed: Description is too long (maximum is 160 characters)"
Do something
if tweepy.TweepError is "Failed to send request: Invalid request URL: http://api.twitter.com/1/account/update_profile.json?location=%E5%85%B5%E5%BA%A"
Do something
if tweepy.TweepError is "[{u'message': u'Over capacity', u'code': 130}]"
Do something
Is the only way to classify error is to compare e with string, for example, Account update failed: Description is too long (maximum is 160 characters)?

Right, it is the only way now. There is only one TweepError exception defined. It's raised throughout the app with different text.
Here's the relevant open issue on github. So there is a chance that it'll be improved in the future.

How to catch DNSLookupFailedError in Python on GAE?

I test URLs provided by people with urlfetch to catch wrong links.
result = urlfetch.fetch(url)
When I provide an URL such as «http://qwerty.uiop» the log says there was «DNSLookupFailedError», but this code wouldn't catch it:
except urlfetch.DNSLookupFailedError:
self.error(400)
self.response.out.write(
'Sorry, there was a problem with URL "' + url + '"')
I also tried "except urlfetch.Error:" and "except urlfetch.DownloadError:"
What am I doing wrong, and is there another way to accomplish what I'm trying to do?

In the local developer environment and in production I actually see a different exception: DownloadError. Catching that worked fine for me.
try:
result = urlfetch.fetch('http://qwerty.uiop')
except urlfetch.DownloadError:
self.response.write('Oops!')