8.0 - Templating - Jinja2

8.1 - Introduction

• Templating = Using variable substitution e.g. {{ name }} for variable name
• Jinja2 Templating defined by either {{ }} or {% %}
• Jinja = Templating language designed for Python.

String Manipulation - Filters

• Make string substitute uppercase: {{ var name | upper }}
• Lowercase: {{ var name | upper }}
• Title Case: {{ var name | title }}
• Replace with a given value {{ var name | replace("<Original Value>", "<Replacing Value>" }}
• Use defaults: {{ var name | default("<Default Value>") }}

Filters - List and Set

• When working with lists and sets:
• Get minimum: {{ [1,2,3] | min }}
• Get maximum: {{ [1,2,3] | max }}
• Get unique values: {{ [1,2,3] | unique }}
• Get unique values across multiple arrays: {{ [1,2,3,4] | union( [4,5] ) }}
• Find common values across multiple arrays {{ [1,2,3,4] | intersect( [4,5] ) }}
• Get a random number: {{ 100 | random }}
• Join an array of strings: {{ "word1", "word2", "word3", "word4" | join(" ") }}

Filters - File

• Get file basename:
• Windows hosts: {{ "/path/to/file" | win_basename }}
• Linux Hosts {{ "/path/to/file" | basename }}
• Get the drive letter from a path {{ "/path/to/file" | win_splitdrive }}
• Returns an array with the first entry being the drive letter, to isolate it, add an extra pipe | first

• For the last filter: | last

• Many more filters are available at jinja.pcoo.org/docs

• Additional guidance also available in the Ansible documentation.