Tag: ansible variable data type

Ansible – Data Structure / Collection data type

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Ansible support complex data type like data structure or collection types like List, Map, etc.

We have covered Ansible Variables, and the Ansible Data Types in our earlier post,

Ansible Data Structure or Collection types supports,

  • Lists, are a collection of items and are generally represented using the [] brackets. The items in the list are indexed and can be accessed using index values starting from zero.
  • We can define a list in two ways, as shown below.
vars:
    var_list: ['db_server', 'web_server', 'app_server']
    var_list_2:
    - 'db'
    - 'web'
    - 'app'
  • A Map is similar to the python dictionary. In Map, you can have key, and value pairs.
  • We can define Map in two ways as shown below.
vars:
    var_dict: {'db_server':'mysql', 'web_server':'apache', 'app_server':'php'}
    var_dict_2:
     'db': 'mysql'
     'web': 'apache'
     'app': 'php'

Example code of List and Map,

---
 # Ansible Data Structure
 - name: Playbook - Ansible Data Structure 
   hosts: localhost
   vars:
    # Ansible List
    var_list: ['db_server', 'web_server', 'app_server']
    var_list_2:
    - 'db'
    - 'web'
    - 'app'
    # Ansible Map
    var_dict: {'db_server':'mysql', 'web_server':'apache', 'app_server':'php'}
    var_dict_2:
     'db': 'mysql'
     'web': 'apache'
     'app': 'php'

   tasks:
   - name: Lets print the list
     debug: var=var_list
   
   - name: Lets print the dict
     debug: var=var_dict

   - name: lets print the second list
     debug: var=var_list_2

   - name: lets print the second dict
     debug: var=var_dict_2

   - name: Lets print specific list value
     debug:
      msg:
       - "The second value of list is {{var_list[1]}}"
       - "The second value of the dict is {{var_dict_2['web']}}"
       - Another method of calling value from dict {{var_dict.get('app_server')}}
       - lets get all the dict keys {{var_dict.keys()}}
       - lets get all the dict values {{var_dict.values()}}

The below screencap shows the output of the list and map using different methods as defined in the above code.

Ansible – Data Structure

Ansible – variable data type

admin

Ansible variables support various data types, similar to many programming languages.

We have covered the Ansible variables in our earlier post, Ansible Variables

Ansible does offer us a way to check the type of variables used in our playbooks. To check the variables data types in your playbook, use the “type_debug” keyword.

Example:

- name: Playbook - to get the data types
   hosts: localhost
   vars: 
    y: 15
    server_name: "db_server"
    boolean_value: false
    float_value: 10.10

   tasks:
   - name: Lets get the data type
     debug:
      msg:
       - "Variable : {{y}}, is of type {{y | type_debug}}"
       - "Variable : {{server_name}}, is of type {{server_name | type_debug}}"
       - "Variable : {{boolean_value}}, is of type {{boolean_value | type_debug}}"
       - "Variable : {{float_value}}, is of type {{float_value | type_debug}}"

As you can see in the above code, we need to pass pipe operator | and then type_debug.

ansible variable data type