Empty string in Ansible responses - ansible

Question

I am developing RouterOS network module for Ansible 2.5.
RouterOS shell can print a few messages that should be detected in on_open_shell() event and either skipped or dismissed automatically. These are Do you want to see the software license? [Y/n]: and a few others, all of which are well documented here in the MikroTik Wiki.
Here is how I'm doing this:
def on_open_shell(self):
try:
if not prompt.strip().endswith(b'>'):
self._exec_cli_command(b' ')
except AnsibleConnectionFailure:
raise AnsibleConnectionFailure('unable to bypass license prompt')
It indeed does bypass the license prompt. However it seems that the \n response from the RouterOS device counts as a reply for the actual commands that follow. So, if I have two tasks in my playbook like this:
---
- hosts: routeros
gather_facts: no
connection: network_cli
tasks:
- routeros_command:
commands:
- /system resource print
- /system routerboard print
register: result
- name: Print result
debug: var=result.stdout_lines
This is the output I get:
ok: [example] => {
"result.stdout_lines": [
[
""
],
[
"uptime: 12h33m29s",
" version: 6.42.1 (stable)",
" build-time: Apr/23/2018 10:46:55",
" free-memory: 231.0MiB",
" total-memory: 249.5MiB",
" cpu: Intel(R)",
" cpu-count: 1",
" cpu-frequency: 2700MHz",
" cpu-load: 2%",
" free-hdd-space: 943.8MiB",
" total-hdd-space: 984.3MiB",
" write-sect-since-reboot: 7048",
" write-sect-total: 7048",
" architecture-name: x86",
" board-name: x86",
" platform: MikroTik"
]
]
}
As you can see, the output seems to be offset by 1. What should I do to correct this?

Answer 1

It turns out that the problem was in the regular expression that defined the shell prompt. I had it defined like this:
terminal_stdout_re = [
re.compile(br"\[\w+\#[\w\-\.]+\] ?>"),
# other cases
]
It did not match the end of prompt which caused Ansible to think that there was a newline before the actual command output. Here is the correct regexp:
terminal_stdout_re = [
re.compile(br"\[\w+\#[\w\-\.]+\] ?> ?$"),
# other cases
]