How to properly handle this error while using multi thread

Question

I am using napalm library to connect to Arista vEOS using GNS3. I intentionally put the wrong IP just to see how my codes handle an error. But the try and except did not work as intended.

import napalm
import concurrent.futures

def napalm_library(ip):
    driver = napalm.get_network_driver(ip[3])
    optional = {"transport": "telnet"}

    with driver(hostname=ip[0], username=ip[1], password=ip[2], optional_args=optional) as device:
         device.load_merge_candidate("test.txt")
         device.commit_config()

with concurrent.futures.ThreadPoolExecutor() as executor:
    t = executor.submit(napalm_library, ['1.1.1.1','username','pass','ios'])
    try:
        t.result()
    except TimeoutError as err1:
        print(err1)

instead it gave me this TimeoutError eventho I already try to catch the TimeoutError.

[WinError 10060] A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond
Traceback (most recent call last):
  File "C:\Python38-32\lib\site-packages\pyeapi\eapilib.py", line 436, in send
    self.transport.endheaders(message_body=data)
  File "C:\Python38-32\lib\http\client.py", line 1225, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "C:\Python38-32\lib\http\client.py", line 1004, in _send_output
    self.send(msg)
  File "C:\Python38-32\lib\http\client.py", line 944, in send
    self.connect()
  File "C:\Python38-32\lib\http\client.py", line 1392, in connect
    super().connect()
  File "C:\Python38-32\lib\http\client.py", line 915, in connect
    self.sock = self._create_connection(
  File "C:\Python38-32\lib\socket.py", line 808, in create_connection
    raise err
  File "C:\Python38-32\lib\socket.py", line 796, in create_connection
    sock.connect(sa)
TimeoutError: [WinError 10060] A connection attempt failed because the connected party did not properly r

Enlighten me, as how am i should handle the error.

Answer 1

You should catch the error when you are retrieving the thread result like so:

from concurrent.futures import ThreadPoolExecutor


with ThreadPoolExecutor() as executor:
    t = executor.submit(napalm_library, ip_addresses)

    try:
        t.result()
    except TimeoutError as err:
        print(err)