如何在异常后继续循环？

Question

I have a code where im looping through hosts list and appending connections to connections list, if there is a connection error, i want to skip that and continue with the next host in the hosts list.

Heres what i have now:

def do_connect(self):
    """Connect to all hosts in the hosts list"""
    for host in self.hosts:
        try:
            client = paramiko.SSHClient()
            client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            client.connect(host['ip'], port=int(host['port']), username=host['user'], timeout=2)
        except:
            pass
            #client.connect(host['ip'], port=int(host['port']), username=host['user'], password=host['passwd'])

        finally:
            if paramiko.SSHException():
                pass
            else:
                self.connections.append(client)

This does not work properly, if connection fails it just loops the same host again and again forever, till it establishes connection, how do i fix this?

Answer 1

Your own answer is still wrong on quite a few points...

import logging
logger = logging.getLogger(__name__)

def do_connect(self):
    """Connect to all hosts in the hosts list"""
    for host in self.hosts:
        # this one has to go outside the try/except block
        # else `client` might not be defined.
        client = paramiko.SSHClient()
        try:
            client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            client.connect(host['ip'], port=int(host['port']), username=host['user'], timeout=2)

        # you only want to catch specific exceptions here
        except paramiko.SSHException as e:
            # this will log the full error message and traceback
            logger.exception("failed to connect to %(ip)s:%(port)s (user %(user)s)", host) 

            continue
        # here you want a `else` clause not a `finally`
        # (`finally` is _always_ executed)
        else:
            self.connections.append(client)

Answer 2

Ok, got it working, i needed to add the Continue, mentioned by Mark and also the previous if check inside finally was always returning true so that was fixed aswell.

Here is the fixed code, that doesnt add failed connections and continues the loop normally after that:

def do_connect(self):
    """Connect to all hosts in the hosts list"""
    for host in self.hosts:
        try:
            client = paramiko.SSHClient()
            client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            client.connect(host['ip'], port=int(host['port']), username=host['user'], timeout=2)
        except:
            continue
            #client.connect(host['ip'], port=int(host['port']), username=host['user'], password=host['passwd'])

        finally:
            if client._agent is None:
                pass
            else:
                self.connections.append(client)