Ansible variable from output - ansible

Question

I would like to extract some words from an Ansible output. For example, I would like to extract from sudo monit status command the bolded words(** **) and store them in 2 variables(let's say variable 'A' for OK and variable 'B' for the uptime period) which will be used later on into a Jinja2 template:
[ansible#server ~]$ sudo monit status
Monit 5.25.1 uptime: 3m
System 'server'
status **OK**
monitoring status Monitored
monitoring mode active
on reboot start
load average [0.03] [0.07] [0.11]
cpu 0.1%us 0.2%sy 0.0%wa
memory usage 338.1 MB [18.4%]
swap usage 0 B [0.0%]
uptime **29m**
boot time Fri, 30 Mar 2018 11:56:12
data collected Fri, 30 Mar 2018 12:25:24
To accomplish this, I have started an Ansible playbook, but in this way, I'm taking all information from the output:
--- #Health check
- hosts: appserver
connection: ssh
sudo: yes
user: ansible
tasks:
- name: Monitor the status
shell: "{{item}}"
with_items:
- monit status
register: monitinfo
tags: basic_monitoring
- debug: var=monitinfo
Any idea how this can be accomplished?
Thank you,
Romain

Answer 1

I see two methods to solve your issue:
Method 1: Converting the shell output to YAML or JSON and parse it with from_yaml or from_json
In your particular case, as the output is already pre-formatted in a key-value way, it would be most convenient to just convert it to a format that Ansible understands (e.g. YAML/JSON). For example, you could convert the output to YAML by deleting the irrelevant lines with tail and then use the regex_replace filter for the rest. Afterwards, use the from_yaml filter to parse everything into Ansible variables. Example:
- name: Fetch the monit status
shell: "monit status | tail -n +3"
register: monit_status_raw
- name: Extract monit variables
set_fact:
monit_status: "{{ monit_status_raw.stdout | regex_replace('\s\s([a-z]+\s[a-z]*)\s+', '\\1: ') | regex_replace('\s:', ':') | regex_replace('([a-z])\s([a-z])', '\\1_\\2') | from_yaml }}"
- name: Show server status
debug: var=monit_status['status']
- name: Show server uptime
debug: var=monit_status['uptime']
If everything went fine, the monit_status variable should contain a dictionary of all variables that the monit status command provided. You can access the variables you want as shown in the debug commands within the example above. In case the code does not work already, you could debug the regex_replace filter with
- debug: msg="{{ monit_status_raw.stdout | regex_replace('\s\s([a-z]+\s[a-z]*)\s+', '\\1: ') | regex_replace('\s:', ':') | regex_replace('([a-z])\s([a-z])', '\\1_\\2') | from_yaml }}"
and check whether the output is really YAML already. In case not, the regular expression has to be adjusted so that in the end, the output is YAML-conform.
Method 2: Searching for the values you need with the regex_search filter
In similar cases where just a single variable has to be extracted or if the output cannot be easily converted to JSON or YAML with regex_replace, the regex_search filter would be the right choice. In your case, the regex_search solution would look similar to this:
- name: Fetch the monit status
shell: "monit status | tail -n +3"
register: monit_status_raw
- name: Extract monit variables
set_fact:
monit_status: "{{ monit_status_raw.stdout | regex_search('\s\sstatus\s+(.*)') }}"
monit_uptime: "{{ monit_status_raw.stdout | regex_search('\s\suptime\s+(.*)') }}"
- name: Show server status
debug: var=monit_status
- name: Show server uptime
debug: var=monit_uptime
Hint: Online regex testers like regex101.com can help you to find the right expression.