For custom Jinja filters a method should return the desired formatted value and for Jinja tests a method should contain the logic to return a boolean value. This looks and works a lot like the UNIX practice of … Custom Jinja filters and tests are easy to create because they are backed by regular Python methods. Format datetime in a Jinja2 template. In this code, the title filter will take article.title and return a title-cased version, which will then be printed to the template. jinja2.environmentfilter (f) ¶ Decorator for marking environment dependent filters. After looking at the above example, experienced developers might think that it was stupid to use a context processor for the purpose. Custom filters are a powerful tool to move some of your complex text transformations to some more readable python code rather than the alternative of long chaining of the built-in ansible filters. Custom template tags and filters¶. If you use this post to build your own Ansible Jinja2 filter, please share it with me in the comments :-) Custom filters & tests in Jinja. In my Flask app, I created a new module file and added the features I needed in the way of two custom filters. Jinja2 custom filters to the rescue! Jinja2 filters even accept additional arguments, as follows: In addition to those, Ansible supplies many more. See builtin filters in the official Jinja2 template documentation.. The current Environment is passed to the filter as first argument. Django’s template language comes with a wide variety of built-in tags and filters designed to address the presentation logic needs of your application. Nevertheless, you may find yourself needing functionality that is not covered by the core set of template primitives. flask documentation: Custom Jinja2 Template Filters. As the documentation for custom filters explains, these are just standard python functions: Possible implementation: jinja_ext package near hooks and cookiecutter.json , add it to path during template render and pass all underlying module path strings to Environment constructor. Creating a Custom Jinja2 Filter. Filters in Jinja2 are a way of transforming template expressions from one kind of data into another. The Jinja2 filter will then process it and return the resulting data. One can simply write a filter to get the same result; this will make things much cleaner. Parameter Details; value: The value passed in by Jinja, to be filtered: args: Extra arguments to be passed into the filter function In the preceding example, myvar is a variable; Ansible will pass myvar to the Jinja2 filter as an argument. jinja2.contextfilter (f) ¶ Decorator for marking context dependent filters. Filters can either be defined in a method and then added to Jinja's filters dictionary, or defined in a method decorated with Flask.template_filter… In this post, you learned how to extend Ansible by writing a custom Jinja2 filter. Jinja2 ships with many of these. Looking at the play output, you can see the app_names variable contains the expected result of ["web", "worker", "relay"], and the playbook finished with all tasks completing successfully.. Next steps. BTW, instead of filters Cookiecutter can allow to register Jinja2 extensions which will give even more flexibility - anything up to defining custom tags. These helper functions and classes are useful if you add custom filters or functions to a Jinja environment. A filter can be written to display the descriptive name of the product as shown below. The following are 30 code examples for showing how to use jinja2.Environment().These examples are extracted from open source projects. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example.