The below function parses the cisco command output,stores the output in dictionary and returns the value for a given key. This function works as expected when the dictionary contains the output. However, if the command returns no output at all the length of dictionary is 0 and the function returns a key error . I have used exception KeyError: But this doesn't seem to work.
from qa.ssh import Ssh
import re
class crypto:
def __init__(self, username, ip, password, machinetype):
self.user_name = username
self.ip_address = ip
self.pass_word = password
self.machine_type = machinetype
self.router_ssh = Ssh(ip=self.ip_address,
user=self.user_name,
password=self.pass_word,
machine_type=self.machine_type
)
def session_status(self, interface):
command = 'show crypto session interface '+interface
result = self.router_ssh.cmd(command)
try:
resultDict = dict(map(str.strip, line.split(':', 1))
for line in result.split('\n') if ':' in line)
return resultDict
except KeyError:
return False
test script :
obj = crypto('uname', 'ipaddr', 'password', 'router')
out = obj.session_status('tunnel0')
status = out['Peer']
print(status)
Error
Traceback (most recent call last):
File "./test_parser.py", line 16, in <module>
status = out['Peer']
KeyError: 'Peer'
The KeyError did not happend in the function session_status,it is happend in your script at status = out['Peer'].So your try and except in session_status will not work.you should make a try and except for status = out['Peer']:
try:
status = out['Peer']
except KeyError:
print 'no Peer'
or :
status = out.get('Peer', None)
Your exception is not in the right place. As you said you just return an empty dictionary with your function. The exception is trying to lookup the key on empty dictionary object that is returned status = outertunnel['Peer']. It might be easier to check it with the dict get function. status = outertunnel.get('Peer',False) or improve the test within the function session_status, like testing the length to decide what to return False if len(resultDict) == 0
This explains the problem you're seeing.
The exception happens when you reference out['Peer'] because out is an empty dict. To see where the KeyError exception can come into play, this is how it operates on an empty dict:
out = {}
status = out['Peer']
Throws the error you're seeing. The following shows how to deal with an unfound key in out:
out = {}
try:
status = out['Peer']
except KeyError:
status = False
print('The key you asked for is not here status has been set to False')
Even if the returned object was False, out['Peer'] still fails:
>>> out = False
>>> out['Peer']
Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
out['Peer']
TypeError: 'bool' object is not subscriptable
I'm not sure how you should proceed, but dealing with the result of session_status not having the values you need is the way forward, and the try: except: block inside the session_status function isn't doing anything at the moment.
Related
KeyError exception object contains args attribute. This is a list and it contains a key name which user tries to access within a dictionary.
Is it possible to figure out dictionary name which does not contain that key and which caused an exception while trying to access the key within it?
Example
data = {"my_key": "my_value"}
try:
data["unknown_key"] except KeyError as e:
print("key name: ", e.args[0])
print("dictionary name: ", e.???) # Here I would need to know the the name of a variable which stores the dictionary is "data"
You can kinda hack this with Python 3.11+, since the traceback contains fine-grained information about where the error happened.
import ast
import linecache
import traceback
data = {"my_key": "my_value"}
flurk = data
try:
data["flep"] = data["my_key"] + flurk["unknown_key"]
except KeyError as e:
# Find the last frame where the exception occurred, formatted as a FrameSummary
err_frame = traceback.TracebackException.from_exception(e).stack[-1]
if err_frame.lineno == getattr(err_frame, "end_lineno", -1): # If we can reliably find the line,
# ... read the line,
line = linecache.getline(err_frame.filename, err_frame.lineno)
# find the "marked segment" in it,
fragment = line[err_frame.colno:err_frame.end_colno]
# ... and parse it as an expression.
expr: ast.Expression = ast.parse(fragment, mode='eval')
# Check we're dealing with a subscript (index) node...
assert isinstance(expr.body, ast.Subscript)
# ... and extract the main parts of the expression.
subscriptee = ast.unparse(expr.body.value)
subscript = ast.unparse(expr.body.slice)
else:
subscriptee = None # No idea
subscript = e.args[0] # Just use the exception message
raise RuntimeError(f"KeyError with {subscriptee=!r}, {subscript=!r}") from e
prints out
Traceback (most recent call last):
File "scratch_679.py", line 8, in <module>
data["flep"] = data["my_key"] + flurk["unknown_key"]
~~~~~^^^^^^^^^^^^^^^
KeyError: 'unknown_key'
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "scratch_679.py", line 27, in <module>
raise RuntimeError(f"KeyError with {subscriptee=!r}, {subscript=!r}") from e
RuntimeError: KeyError with subscriptee='flurk', subscript="'unknown_key'"
so you can see the subscriptee name is flurk.
I have this code to check if a person exists given their id. If they do exist, it has to print the name and last name. If they don't exists, it has to print some error. The thing is, my code only prints the error even though I tried the code with a number I know corresponds to an existing person. How do I fix that?
This is my view:
from django.shortcuts import render, HttpResponse
import requests
from django.views.generic import FormView
from .forms import MonotributoForm
from app.ws_sr_padron import get_persona
class ConstanciaInscripcion(FormView):
def get(self, request):
return render(request, 'app/constancia-inscripcion.html')
def post(self,request):
form = MonotributoForm(request.POST)
try:
cuit_r = int(request.POST.get('cuit', '-1')) # Get 'cuit' with default of -1
except ValueError:
pass
response= get_persona(cuit_r)
if response is True:
print(response["persona"]['name'])
print(response['persona']['lastname'])
else:
print("cuit doesn't exist")
if form.is_valid():
cuit = form.cleaned_data.get('cuit')
email = form.cleaned_data.get('email')
cuit.save()
email.save()
return HttpResponseRedirect('app/constancia-inscripcion.html')
return render(request, 'app/constancia-inscripcion.html')
The code for get_persona (I cannot modify this as I did not write it and it was given to me this way):
def get_persona(cuit_requested, ta_sign=None, ta_token=None):
try:
if ta_sign is None and ta_token is None:
ta_sign, ta_token = wsaa.get_ta_sign_token('ws_sr_padron_a13')
client = Client(padron13_wsdl)
response = client.service.getPersona(
sign=ta_sign,
token=ta_token,
cuitRepresentada=cuit_consultante,
idPersona=cuit_requested,
)
return serialize_object(response, target_cls=dict)
except Fault as e:
if e.message == 'No person with Id':
return None
elif e.message == 'inactive':
return 'inactive'
print('Error: ', e)
return None
except Exception as e:
print('Error: ', e)
return None
Result of get_persona with an existing id (tried on terminal):
{'metadata': {'fechaHora': datetime.datetime(2021, 3, 4, 15, 13, 54, 738000, tzinfo=<FixedOffset '-03:00'>), 'servidor': 'linux11b'}, 'persona': {'apellido': 'POLAR', 'estadoClave': 'ACTIVO', 'idPersona': 2231230211, 'mesCierre': 12, 'nombre': 'MAURICIO', 'tipoClave': 'CUIT'}}
The output of response on it's own seems to be None for some reason.
The issue is due to the conditional in your code: if response is True.
If you look at the value that get_persona returns, it can be the result of the function serialize_object(...), None, or "inactive".
If the serialize_object(...) function returns a None or the string "inactive", the statement response is True will be false.
>>> type(True)
bool
>>> type({"a": 1})
dict
>>> type("inactive")
str
# To test this, I created this function
>>> def test_response(response):
return response is True
>>> test_response(None)
False
>>> test_response({"persona": True})
False
>>> test_response("inactive")
False
# The only value of response that `is True` is the value `True` itself!
>>> test_response(True)
True
What you want to do is change your conditional to check for a useful response value. In this case, you could test if the response value is a dict, but what if it doesn't have the persona value -- or what if the persona exists, but it doesn't have a nombre?
>>> response = {"a": 1}
>>> response["persona"]["nombre"]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
KeyError: 'persona'
>>> response = {"persona": None}
>>> response["persona"]["nombre"]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'NoneType' object is not subscriptable
A better solution than an if statement would be a try/except, which can handle both types of errors gracefully and default to the invalid/error case.
response = get_persona(cuit_r)
try:
nombre = response["persona"]["nombre"]
apellido = response["persona"]["apellido"]
except KeyError:
nombre, apellido = None, None
print("get_persona response is missing keys!")
except TypeError:
nombre, apellido = None, None
print("get_persona response had wrong type!")
else:
print("get_persona returned a valid response!")
print("nombre:", nombre)
print("apellido:", apellido)
Update #1
Based on your comments, it also sounds like you're having trouble with the cuit_r value as well. You should change your code to properly handle the possible exceptions as separate statements:
try:
cuit_r = int(request.POST["cuit"])
except KeyError:
print("The key 'cuit' was missing from the POST data.")
print("Defaulting to cuit_r = -1")
cuit_r = -1
except TypeError:
print(
"The 'cuit' value is the wrong type:",
type(request.POST["cuit"]),
)
print("Defaulting to cuit_r = -1")
cuit_r = -1
print(f"Resolved value of cuit_r: {type(cuit_r).__name__}({cuit_r!r})")
I'm running the following:
for server in server_list:
for item in required_fields:
print item, eval(item)
There is a possibility that some keys may not exist, but worse it's represented on a parent key not the one I'm scanning for.
So I'm scanning the json for the following key:
server['server_management']['server_total_cost_of_ownership']['description']
Which doesn't exist but it's actually the parent that is null:
server['server_management']['server_total_cost_of_ownership']
How do I write my code to account for this? It's not giving a key error. Right now I get the following traceback:
Traceback (most recent call last):
File "C:/projects/blah/scripts/test.py", line 29, in <module>
print item, eval(item)
File "<string>", line 1, in <module>
TypeError: 'NoneType' object has no attribute '__getitem__'
Full code:
import csv
import json
import os
import requests
import sys
required_fields = ["server['server_name']","server['server_info']['asset_type']['display_name']",
"server['asset_status']['display_name']", "server['record_owner']['group_name']",
"server['server_management']['server_total_cost_of_ownership']['description']",
"server['server_management']['primary_business_owner']['name']",
"server['environment']['display_name']", "server['is_virtual']",
"server['managed_by']['display_name']", "server['server_info']['billable_ibm']",
"server['server_info']['billing_sub_type']['display_name']",
"server['server_info']['serial_number']", "server['location']['display_name']",
"server['inception_date']", "server['server_info']['decommission_date']" ]
# Query API for all servers
def get_servers_info():
servers_info = requests.get('url')
return servers_info.json()
def get_server_info(sid):
server_info = requests.get('url')
return server_info.json()
server_list = get_servers_info()
for server in server_list:
for item in required_fields:
print item, eval(item)
In fact you should avoid eval. After the json load since you know the key name, you can use a list to go deeper in the tree.
server['server_management']['primary_business_owner']['name']" => ["server_management', 'primary_business_owner', 'name']
Here a snippet for a json validation against a list of required fields.
data={
"d": {
"p":{
"r":[
"test"
]
}
},
"a": 3
}
def _get_attr(dict_, attrs):
try:
src = attrs[:]
root = attrs.pop(0)
node = dict_[root]
null = object()
for i, attr in enumerate(attrs[:]):
try:
node = node.get(attr, null)
except AttributeError:
node = null
if node is null:
# i+2 pop and last element
raise ValueError("%s not present (level %s)" % (attr, '->'.join(src[: i+2])))
return node
except KeyError:
raise ValueError("%s not present" % root)
# assume list of required field
reqs = [
["d", "p", "r"],
["d"],
["k"],
["d", "p", "r", "e"],
]
for req in reqs:
try:
_get_attr(data, req)
except ValueError as E:
print(E)
# prints
# k not present
# e not present (level d->p->r->e)
Ignoring the context of the code and not understanding the use of eval here, the way to do this is to use .get() and seed it with reasonable defaults.
For example:
server['server_management']['server_total_cost_of_ownership']['description']
Can be:
server.get('server_management', {}).get('server_total_cost_of_ownership', {}).get('description', '')
Then if any of the keys do not exist you will always get back an empty description ''.
Your problem here is totally unrelated to using eval[1]. The exception you get is the same as if the code would have been there directly. What you are running (via eval) is:
a = server['server_management']
b = a['server_total_cost_of_ownership']
c = b['description']
Yet, b is None, so resolving it to c will fail. Like a KeyError, you can also catch a TypeError:
for server in server_list:
for item in required_fields:
try:
print item, eval(item)
except TypeError:
print("Guess you're lucky you didn't include a fork bomb in your own code to eval.")
You may of course alternatively pass, print the offending item, open a browser to some page or do whatever error handling is appropriate given your input data.
[1] While not bickering around, I've made a new answer that works without eval. You can use precisely the same error handling:
for server in server_list:
for item in required_fields:
value = server
for key in parse_fields(field):
try:
value = value[key]
except TypeError:
print("Remember Kiddo: Eval is Evil!")
break
else: # for: else: triggers only if no break was issued
print item, value
I am trying to Retrieve multiple keyword term tweets by following specific group of users. Using the code below:
I have posted one more code before that regarding issues for value error:
I figure it out somehow but again I am stuck because of this traceback
import tweepy
from tweepy.error import TweepError
consumer_key=('ABC'),
consumer_secret=('ABC'),
access_key=('ABC'),
access_secret=('ABC')
auth = tweepy.OAuthHandler(consumer_key, consumer_secret)
auth.set_access_token(access_key, access_secret)
api=tweepy.API(auth)
class CustomStreamListener(tweepy.StreamListener):
def on_status(self, status):
try:
print "%s\t%s\t%s\t%s" % (status.text,
status.author.screen_name,
status.created_at,
status.source,)
except Exception, e:
print error
#def filter(self, follow=None, track=None, async=False, locations=None):
#self.parameters = {}
#self.headers['Content-type'] = "application/x-www-form-urlencoded"
#if self.running:
#raise TweepError('Stream object already connected!')
#self.url = '/%i/statuses/filter.json?delimited=length' % STREAM_VERSION
def filter(self, follow=None, track=None, async=False, locations=None):
self.parameters = {}
self.headers['Content-type'] = "application/x-www-form-urlencoded"
if self.running:
raise TweepError('Stream object already connected!')
self.url = '/%i/statuses/filter.json?delimited=length' % STREAM_VERSION
if obey:
self.parameters['follow'] = ' '.join(map(str, obey))
if track:
self.parameters['track'] = ' '.join(map(str, track))
if locations and len(locations) > 0:
assert len(locations) % 4 == 0
self.parameters['locations'] = ' '.join('%.2f' % l for l in locations)
self.body = urllib.urlencode(self.parameters)
self.parameters['delimited'] = 'length'
self._start(async)
def on_error(self, status_code):
return True
streaming_api = tweepy.streaming.Stream(auth, CustomStreamListener(), timeout=60)
list_users = ['17006157','59145948','157009365','16686144','68044757','33338729']#Some ids
list_terms = ['narendra modi','robotics']#Some terms
streaming_api.filter(follow=[list_users])
streaming_api.filter(track=[list_terms])
I am getting a traceback:
Traceback (most recent call last):
File "C:\Python27\nytimes\26052014\Multiple term search with multiple addreses.py", line 49, in <module>
streaming_api.filter(follow=[list_users])
File "build\bdist.win32\egg\tweepy\streaming.py", line 296, in filter
encoded_follow = [s.encode(encoding) for s in follow]
AttributeError: 'list' object has no attribute 'encode'
Please help me resolving the issue.
You define list_users here
list_users = ['17006157','59145948','157009365','16686144','68044757','33338729']
and then you pass it to streaming_api.filter like this
streaming_api.filter(follow=[list_users])
When the streaming_api.filter function is iterating over the value you pass as follow, it gives the error
AttributeError: 'list' object has no attribute 'encode'
The reason for this is as follows
You call streaming_api.filter like this
streaming_api.filter(follow=[list_users])
Here
streaming_api.filter(follow=[list_users])
you are trying to pass your list as value for follow, however because you put list_users in enclosing [] you are creating a list in a list. Then streaming_api.filter iterates over follow, calling .encode on each entry as we see here
[s.encode(encoding) for s in follow]
But the entry s is a list while it should be a string.
That is because you accidentally created a list in a list like you can see above.
The solution is simple. Change
streaming_api.filter(follow=[list_users])
to
streaming_api.filter(follow=list_users)
To pass a list to a function, you can just specify the name. No need to enclose it in []
Same applies to the last line. Change
streaming_api.filter(track=[list_terms])
to
streaming_api.filter(track=list_terms)
I have a piece of code that acts as a listener of a button and evaluates whether some fields above this button are filled in:
def goListener(self):
if all( [self.nme.get() != "", self.dsc.get() != "", self.imp.get != ""] ):
name = self.nme.get()
desc = self.dsc.get()
while True:
try:
imp = int(self.imp.get())
break
except:
imp = int(self.imp.get())
When I run this program with different fields filled in or otherwise, it gets it right and produces the error message I ask it to with every combination except where nme and dsc are filled in but imp isn't, this produces the error message:
Traceback (most recent call last):
File "C:\Python33\lib\tkinter\__init__.py", line 1442, in __call__
return self.func(*args)
File "C:\Python33\todo.py", line 68, in goListener
imp = int(self.imp.get())
ValueError: invalid literal for int() with base 10: ''
This is running the except block by the way, which it shouldn't. Is this a problem with the evaluation, or am I missing something here?
You have:
self.imp.get != ""
You are failing to invoke the .get() method. Try:
self.imp.get() != ""
If imp = int(self.imp.get()) throws an error, calling it again outside of a try block will throw the same error.
The except block is for code that should run when there is an exception:
try:
imp = int(self.imp.get())
break
except:
print "Something bad happened"