diff --git a/docs/docsite/rst/user_guide/playbooks_filters.rst b/docs/docsite/rst/user_guide/playbooks_filters.rst index ccc3daa8bc6..f16b2359026 100644 --- a/docs/docsite/rst/user_guide/playbooks_filters.rst +++ b/docs/docsite/rst/user_guide/playbooks_filters.rst @@ -114,6 +114,7 @@ If you are unsure of the underlying Python type of a variable, you can use the ` {{ myvar | type_debug }} +You should note that, while this may seem like a useful filter for checking that you have the right type of data in a variable, you should often prefer :ref:`type tests `, which will allow you to test for specific data types. .. _dict_filter: diff --git a/docs/docsite/rst/user_guide/playbooks_tests.rst b/docs/docsite/rst/user_guide/playbooks_tests.rst index b8eecfb37a1..bbad2fe9906 100644 --- a/docs/docsite/rst/user_guide/playbooks_tests.rst +++ b/docs/docsite/rst/user_guide/playbooks_tests.rst @@ -416,7 +416,82 @@ The following tasks are illustrative of the tests meant to check the status of t .. note:: From 2.1, you can also use success, failure, change, and skip so that the grammar matches, for those who need to be strict about it. +.. _type_tests: +Type Tests +========== + +When looking to determine types, it may be tempting to use the ``type_debug`` filter and compare that to the string name of that type, however, you should instead use type test comparisons, such as: + +.. code-block:: yaml + + tasks: + - name: "String interpretation" + vars: + a_string: "A string" + a_dictionary: {"a": "dictionary"} + a_list: ["a", "list"] + assert: + that: + # Note that a string is classed as also being "iterable", "sequence" and "mapping" + - a_string is string + + # Note that a dictionary is classed as not being a "string", but is "iterable", "sequence" and "mapping" + - a_dictionary is not string and a_dictionary is mapping + + # Note that a list is classed as not being a "string" or "mapping" but is "iterable" and "sequence" + - a_list is not string and a_list is not mapping and a_list is iterable + + - name: "Number interpretation" + vars: + a_float: 1.01 + a_float_as_string: "1.01" + an_integer: 1 + an_integer_as_string: "1" + assert: + that: + # Both a_float and an_integer are "number", but each has their own type as well + - a_float is number and a_float is float + - an_integer is number and an_integer is integer + + # Both a_float_as_string and an_integer_as_string are not numbers + - a_float_as_string is not number and a_float_as_string is string + - an_integer_as_string is not number and a_float_as_string is string + + # a_float or a_float_as_string when cast to a float and then to a string should match the same value cast only to a string + - a_float | float | string == a_float | string + - a_float_as_string | float | string == a_float_as_string | string + + # Likewise an_integer and an_integer_as_string when cast to an integer and then to a string should match the same value cast only to an integer + - an_integer | int | string == an_integer | string + - an_integer_as_string | int | string == an_integer_as_string | string + + # However, a_float or a_float_as_string cast as an integer and then a string does not match the same value cast to a string + - a_float | int | string != a_float | string + - a_float_as_string | int | string != a_float_as_string | string + + # Again, Likewise an_integer and an_integer_as_string cast as a float and then a string does not match the same value cast to a string + - an_integer | float | string != an_integer | string + - an_integer_as_string | float | string != an_integer_as_string | string + + - name: "Native Boolean interpretation" + loop: + - yes + - true + - True + - TRUE + - no + - No + - NO + - false + - False + - FALSE + assert: + that: + # Note that while other values may be cast to boolean values, these are the only ones which are natively considered boolean + # Note also that `yes` is the only case sensitive variant of these values. + - item is boolean + .. _builtin tests: https://jinja.palletsprojects.com/en/latest/templates/#builtin-tests .. seealso::