(r10) AnsibleTipsTricks < Main

---+ Ansible tips & tricks

---++ Ansible data types

integer: 3211241 <br>
boolean: true/false <br>
float: 3.141592653 <br>
string: "qwerty" <br>
list: <br>
  - "item 1" <br>
  - "item 2" <br>
dictionary: <br>
  key1: "value 1" <br>
  key2: "value 2" <br>

---++ Dump all variables

<verbatim>
---
- name: dump all
  hosts: all
 
  tasks:
    - name: Print some debug information 
      vars: 
        msg: |
          Module Variables ("vars"):
          --------------------------------
          {{ vars | to_nice_json }} 
          
          Environment Variables ("environment"):
          --------------------------------
          {{ environment | to_nice_json }} 
          
          GROUP NAMES Variables ("group_names"):
          --------------------------------
          {{ group_names | to_nice_json }}
          
          GROUPS Variables ("groups"):
          --------------------------------
          {{ groups | to_nice_json }}
          
          HOST Variables ("hostvars"):
          --------------------------------
          {{ hostvars | to_nice_json }} 

      debug:
        msg: "{{ msg.split('\n') }}"
</verbatim>

---++ manipulating data

---+++ Convert date to Unix time (epoch)

Use "{{ ('2022-01-01' | to_datetime).strftime('%s') }}"

---+++ Extract subitems from list of dictionaries

Use "{{ variable | map(attribute='key_name') | list }}"

---+++ Select items from list of dictionaries

Use "{{ variable | selectattr('key_name', 'match', 'value') | list }}"

Instead of match, you can also use search or regex. See: https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html#testing-strings

See the Jinja2 documentation for a list of available tests: https://jinja.palletsprojects.com/en/2.9.x/templates/#list-of-builtin-tests

---+++ Apply a filter to a list of items

Use "{{ variable | map('<filter>', 'filter_option1', 'filter_option2') | list }}"

For example:

"{{ output.stdout_lines | map('regex_replace', '^(\S+)\s.*$', '\\1') | list }}"

Be careful on the context in which you use this. In some cases you must use a single backslash (displaying a variable with debug for example): '\1'

---+++ Filter a list of strings

Use "{{ variable | select('match', 'some string') | list }}"

Instead of match, you can also use search or regex. See: https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html#testing-strings

---+++ Sort list of dictionaries by subitem

Use "{{ variable | sort(attribute='key_name') }}"

---+++ Searching a string in a when statement

Use: when: my_string is match(pattern)

Instead of match, you can also use search or regex. See: https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html#testing-strings

---+++ Add a string to a string

Use "{{ string1 + string2 }}"

Or: "{{ string1 + ', ' + string2 }}"

---+++ Add item to list

Use "{{ variable | default([]) + [item] }}"

---+++ Add item to dictionary

Use "{{ variable | default({}) | combine({key_name: key_value}) }}"

---++ Replace multiple lines using replace module (lineinfile does not support multi-line regexp)

Example:
<verbatim>
- name: Comment out hint zone "." in named.conf
  replace:
    path: "/etc/named.conf"
    regexp: '^(zone\s+"\."\s+IN\s+{[^\n]*)\n(\s*type\s+hint;[^\n]*)\n(\s*file\s+"named\.ca";[^\n]*)\n(};)'
    replace: '# \1\n# \2\n# \3\n# \4'
</verbatim>

-- %USERSIG{IvoVanGeel - 21 Sep 2021}%
Topic revision: r10 - 28 Jan 2022 - IvoVanGeel
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