Troubleshooting Scrapli Connectivity Issue with Ubuntu Hosts

[ssmyk]

Hello,
I have a problem with the latest version of Scrapli. When I am trying to connect to an Ubuntu host, the communication freezes, and a timeout is triggered:

DEBUG:scrapli.channel:read: b'ping 8.8.8.8 -c 1'
DEBUG:scrapli.channel:write: '\n'
DEBUG:scrapli.channel:read: b'\n'
DEBUG:scrapli.channel:read: b'\x1b[?2004h\x1b]0;user@line5-cpe-0: ~\x07user@line5-cpe-0:~$ ping 8.8.8.8 -c 1\n\x1b[?2004l'
DEBUG:scrapli.channel:read: b'PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.\n'
DEBUG:scrapli.channel:read: b'64 bytes from 8.8.8.8: icmp_seq=1 ttl=117 time=21.2 ms\n\n--- 8.8.8.8 ping statistics ---\n1 packets transmitted, 1 received, 0% packet loss, time 0ms\nrtt min/avg/max/mdev = 21.162/21.162/21.162/0.000 ms\n'
DEBUG:scrapli.channel:read: b'\x1b[?2004h\x1b]0;user@line5-cpe-0: ~\x07user@line5-cpe-0:~$ '
CRITICAL:scrapli.channel:operation timed out, closing connection

It works correctly in version 2023.7.30. I think it's this change that's causing the problem:
https://github.com/carlmontanari/scrapli/pull/316/files

[carlmontanari]

hey @ssmyk would you be able to mess around and try to see if you can get that pattern working with your setup + the existing tests?

[ssmyk]

Yes, I found solution for me, there is a summary:
I compare how regex works with my ssh server output:
2023.7.30: [(b'[?2004h', b''), (b']0;user@line5-cpe-0: ~\x07', b'\x07')]
2024.1.30: [(b'', b'[?2004h', b'', b'', b'[?2004h')]
So it seems the match with \x07 is missing in the newest version. This change in ANSI_ESCAPE_PATTERN fixes it:
rb"([\x07])" -> rb"(.*[\x07])" and then i have match:
[(b'', b'[?2004h\x1b]0;user@line5-cpe-0: ~\x07', b'', b'[?2004h\x1b]0;user@line5-cpe-0: ~\x07', b'')]
or to be more precise:
rb"([\x07])" -> rb"((\]\d).*[\x07])" which provides to:
[(b'', b'[?2004h', b'', b'', b'', b'[?2004h'), (b'', b']0;user@line5-cpe-0: ~\x07', b'', b']0;user@line5-cpe-0: ~\x07', b']0', b'')]

[carlmontanari]

thanks so much @ssmyk can you check out #326 and make sure that sorts things out for ya?

[ssmyk]

Yes, it seems it fixes the issue.