mirror of https://github.com/ansible/ansible.git
Move Jinja2 filters documentation to separate file
Maciej Delmanowski
10 years ago
parent
1cb47c807e
commit
c866a26d81
@ -0,0 +1,369 @@
|
||||
Jinja2 filters
|
||||
==============
|
||||
|
||||
.. contents:: Topics
|
||||
|
||||
Filters in Jinja2 are a way of transforming template expressions from one kind of data into another. Jinja2
|
||||
ships with many of these. See `builtin filters`_ in the official Jinja2 template documentation.
|
||||
|
||||
In addition to those, Ansible supplies many more.
|
||||
|
||||
.. _filters_for_formatting_data:
|
||||
|
||||
Filters For Formatting Data
|
||||
---------------------------
|
||||
|
||||
The following filters will take a data structure in a template and render it in a slightly different format. These
|
||||
are occasionally useful for debugging::
|
||||
|
||||
{{ some_variable | to_nice_json }}
|
||||
{{ some_variable | to_nice_yaml }}
|
||||
|
||||
.. _filters_used_with_conditionals:
|
||||
|
||||
Filters Often Used With Conditionals
|
||||
------------------------------------
|
||||
|
||||
The following tasks are illustrative of how filters can be used with conditionals::
|
||||
|
||||
tasks:
|
||||
|
||||
- shell: /usr/bin/foo
|
||||
register: result
|
||||
ignore_errors: True
|
||||
|
||||
- debug: msg="it failed"
|
||||
when: result|failed
|
||||
|
||||
# in most cases you'll want a handler, but if you want to do something right now, this is nice
|
||||
- debug: msg="it changed"
|
||||
when: result|changed
|
||||
|
||||
- debug: msg="it succeeded"
|
||||
when: result|success
|
||||
|
||||
- debug: msg="it was skipped"
|
||||
when: result|skipped
|
||||
|
||||
.. _forcing_variables_to_be_defined:
|
||||
|
||||
Forcing Variables To Be Defined
|
||||
-------------------------------
|
||||
|
||||
The default behavior from ansible and ansible.cfg is to fail if variables are undefined, but you can turn this off.
|
||||
|
||||
This allows an explicit check with this feature off::
|
||||
|
||||
{{ variable | mandatory }}
|
||||
|
||||
The variable value will be used as is, but the template evaluation will raise an error if it is undefined.
|
||||
|
||||
|
||||
.. _defaulting_undefined_variables:
|
||||
|
||||
Defaulting Undefined Variables
|
||||
------------------------------
|
||||
|
||||
Jinja2 provides a useful 'default' filter, that is often a better approach to failing if a variable is not defined::
|
||||
|
||||
{{ some_variable | default(5) }}
|
||||
|
||||
In the above example, if the variable 'some_variable' is not defined, the value used will be 5, rather than an error
|
||||
being raised.
|
||||
|
||||
|
||||
.. _omitting_undefined_variables:
|
||||
|
||||
Omitting Undefined Variables and Parameters
|
||||
-------------------------------------------
|
||||
|
||||
As of Ansible 1.8, it is possible to use the default filter to omit variables and module parameters using the special
|
||||
`omit` variable::
|
||||
|
||||
- name: touch files with an optional mode
|
||||
file: dest={{item.path}} state=touch mode={{item.mode|default(omit)}}
|
||||
with_items:
|
||||
- path: /tmp/foo
|
||||
- path: /tmp/bar
|
||||
- path: /tmp/baz
|
||||
mode: "0444"
|
||||
|
||||
For the first two files in the list, the default mode will be determined by the umask of the system as the `mode=`
|
||||
parameter will not be sent to the file module while the final file will receive the `mode=0444` option.
|
||||
|
||||
|
||||
.. _list_filters:
|
||||
|
||||
List Filters
|
||||
------------
|
||||
|
||||
These filters all operate on list variables.
|
||||
|
||||
.. versionadded:: 1.8
|
||||
|
||||
To get the minimum value from list of numbers::
|
||||
|
||||
{{ list1 | min }}
|
||||
|
||||
To get the maximum value from a list of numbers::
|
||||
|
||||
{{ [3, 4, 2] | max }}
|
||||
|
||||
.. _set_theory_filters:
|
||||
|
||||
Set Theory Filters
|
||||
------------------
|
||||
All these functions return a unique set from sets or lists.
|
||||
|
||||
.. versionadded:: 1.4
|
||||
|
||||
To get a unique set from a list::
|
||||
|
||||
{{ list1 | unique }}
|
||||
|
||||
To get a union of two lists::
|
||||
|
||||
{{ list1 | union(list2) }}
|
||||
|
||||
To get the intersection of 2 lists (unique list of all items in both)::
|
||||
|
||||
{{ list1 | intersect(list2) }}
|
||||
|
||||
To get the difference of 2 lists (items in 1 that don't exist in 2)::
|
||||
|
||||
{{ list1 | difference(list2) }}
|
||||
|
||||
To get the symmetric difference of 2 lists (items exclusive to each list)::
|
||||
|
||||
{{ list1 | symmetric_difference(list2) }}
|
||||
|
||||
.. _version_comparison_filters:
|
||||
|
||||
Version Comparison Filters
|
||||
--------------------------
|
||||
|
||||
.. versionadded:: 1.6
|
||||
|
||||
To compare a version number, such as checking if the ``ansible_distribution_version``
|
||||
version is greater than or equal to '12.04', you can use the ``version_compare`` filter.
|
||||
|
||||
The ``version_compare`` filter can also be used to evaluate the ``ansible_distribution_version``::
|
||||
|
||||
{{ ansible_distribution_version | version_compare('12.04', '>=') }}
|
||||
|
||||
If ``ansible_distribution_version`` is greater than or equal to 12, this filter will return True, otherwise it will return False.
|
||||
|
||||
The ``version_compare`` filter accepts the following operators::
|
||||
|
||||
<, lt, <=, le, >, gt, >=, ge, ==, =, eq, !=, <>, ne
|
||||
|
||||
This filter also accepts a 3rd parameter, ``strict`` which defines if strict version parsing should
|
||||
be used. The default is ``False``, and if set as ``True`` will use more strict version parsing::
|
||||
|
||||
{{ sample_version_var | version_compare('1.0', operator='lt', strict=True) }}
|
||||
|
||||
.. _random_filter:
|
||||
|
||||
Random Number Filter
|
||||
--------------------
|
||||
|
||||
.. versionadded:: 1.6
|
||||
|
||||
This filter can be used similar to the default jinja2 random filter (returning a random item from a sequence of
|
||||
items), but can also generate a random number based on a range.
|
||||
|
||||
To get a random item from a list::
|
||||
|
||||
{{ ['a','b','c']|random }} => 'c'
|
||||
|
||||
To get a random number from 0 to supplied end::
|
||||
|
||||
{{ 59 |random}} * * * * root /script/from/cron
|
||||
|
||||
Get a random number from 0 to 100 but in steps of 10::
|
||||
|
||||
{{ 100 |random(step=10) }} => 70
|
||||
|
||||
Get a random number from 1 to 100 but in steps of 10::
|
||||
|
||||
{{ 100 |random(1, 10) }} => 31
|
||||
{{ 100 |random(start=1, step=10) }} => 51
|
||||
|
||||
|
||||
Shuffle Filter
|
||||
--------------
|
||||
|
||||
.. versionadded:: 1.8
|
||||
|
||||
This filter will randomize an existing list, giving a different order every invocation.
|
||||
|
||||
To get a random list from an existing list::
|
||||
|
||||
{{ ['a','b','c']|shuffle }} => ['c','a','b']
|
||||
{{ ['a','b','c']|shuffle }} => ['b','c','a']
|
||||
|
||||
note that when used with a non 'listable' item it is a noop, otherwise it always returns a list
|
||||
|
||||
|
||||
.. _math_stuff:
|
||||
|
||||
Math
|
||||
--------------------
|
||||
.. versionadded:: 1.9
|
||||
|
||||
|
||||
To see if something is actually a number::
|
||||
|
||||
{{ myvar | isnan }}
|
||||
|
||||
Get the logarithm (default is e)::
|
||||
|
||||
{{ myvar | log }}
|
||||
|
||||
Get the base 10 logarithm::
|
||||
|
||||
{{ myvar | log(10) }}
|
||||
|
||||
Give me the power of 2! (or 5)::
|
||||
|
||||
{{ myvar | pow(2) }}
|
||||
{{ myvar | pow(5) }}
|
||||
|
||||
Square root, or the 5th::
|
||||
|
||||
{{ myvar | root }}
|
||||
{{ myvar | root(5) }}
|
||||
|
||||
Note that jinja2 already provides some like abs() and round().
|
||||
|
||||
|
||||
.. _hash_filters:
|
||||
|
||||
Hashing filters
|
||||
--------------------
|
||||
.. versionadded:: 1.9
|
||||
|
||||
To get the sha1 hash of a string::
|
||||
|
||||
{{ 'test1'|hash('sha1') }}
|
||||
|
||||
To get the md5 hash of a string::
|
||||
|
||||
{{ 'test1'|hash('md5') }}
|
||||
|
||||
Get a string checksum::
|
||||
|
||||
{{ 'test2'|checksum }}
|
||||
|
||||
Other hashes (platform dependant)::
|
||||
|
||||
{{ 'test2'|hash('blowfish') }}
|
||||
|
||||
To get a sha512 password hash (random salt)::
|
||||
|
||||
{{ 'passwordsaresecret'|password_hash('sha512') }}
|
||||
|
||||
To get a sha256 password hash with a specific salt::
|
||||
|
||||
{{ 'secretpassword'|password_hash('sha256', 'mysecretsalt') }}
|
||||
|
||||
|
||||
Hash types available depend on the master system running ansible,
|
||||
'hash' depends on hashlib password_hash depends on crypt.
|
||||
|
||||
|
||||
.. _other_useful_filters:
|
||||
|
||||
Other Useful Filters
|
||||
--------------------
|
||||
|
||||
To use one value on true and another on false::
|
||||
|
||||
{{ name == "John" | ternary('Mr','Ms') }}
|
||||
|
||||
To concatenate a list into a string::
|
||||
|
||||
{{ list | join(" ") }}
|
||||
|
||||
To get the last name of a file path, like 'foo.txt' out of '/etc/asdf/foo.txt'::
|
||||
|
||||
{{ path | basename }}
|
||||
|
||||
To get the directory from a path::
|
||||
|
||||
{{ path | dirname }}
|
||||
|
||||
To expand a path containing a tilde (`~`) character (new in version 1.5)::
|
||||
|
||||
{{ path | expanduser }}
|
||||
|
||||
To get the real path of a link (new in version 1.8)::
|
||||
|
||||
{{ path | readlink }}
|
||||
|
||||
To work with Base64 encoded strings::
|
||||
|
||||
{{ encoded | b64decode }}
|
||||
{{ decoded | b64encode }}
|
||||
|
||||
To create a UUID from a string (new in version 1.9)::
|
||||
|
||||
{{ hostname | to_uuid }}
|
||||
|
||||
To cast values as certain types, such as when you input a string as "True" from a vars_prompt and the system
|
||||
doesn't know it is a boolean value::
|
||||
|
||||
- debug: msg=test
|
||||
when: some_string_value | bool
|
||||
|
||||
To match strings against a regex, use the "match" or "search" filter::
|
||||
|
||||
vars:
|
||||
url: "http://example.com/users/foo/resources/bar"
|
||||
|
||||
tasks:
|
||||
- shell: "msg='matched pattern 1'"
|
||||
when: url | match("http://example.com/users/.*/resources/.*")
|
||||
|
||||
- debug: "msg='matched pattern 2'"
|
||||
when: url | search("/users/.*/resources/.*")
|
||||
|
||||
'match' will require a complete match in the string, while 'search' will require a match inside of the string.
|
||||
|
||||
To replace text in a string with regex, use the "regex_replace" filter::
|
||||
|
||||
# convert "ansible" to "able"
|
||||
{{ 'ansible' | regex_replace('^a.*i(.*)$', 'a\\1') }}
|
||||
|
||||
# convert "foobar" to "bar"
|
||||
{{ 'foobar' | regex_replace('^f.*o(.*)$', '\\1') }}
|
||||
|
||||
.. note:: If "regex_replace" filter is used with variables inside YAML arguments (as opposed to simpler 'key=value' arguments),
|
||||
then you need to escape backreferences (e.g. ``\\1``) with 4 backslashes (``\\\\``) instead of 2 (``\\``).
|
||||
|
||||
A few useful filters are typically added with each new Ansible release. The development documentation shows
|
||||
how to extend Ansible filters by writing your own as plugins, though in general, we encourage new ones
|
||||
to be added to core so everyone can make use of them.
|
||||
|
||||
.. _builtin filters: http://jinja.pocoo.org/docs/templates/#builtin-filters
|
||||
|
||||
.. seealso::
|
||||
|
||||
:doc:`playbooks`
|
||||
An introduction to playbooks
|
||||
:doc:`playbooks_conditionals`
|
||||
Conditional statements in playbooks
|
||||
:doc:`playbooks_variables`
|
||||
All about variables
|
||||
:doc:`playbooks_loops`
|
||||
Looping in playbooks
|
||||
:doc:`playbooks_roles`
|
||||
Playbook organization by roles
|
||||
:doc:`playbooks_best_practices`
|
||||
Best practices in playbooks
|
||||
`User Mailing List <http://groups.google.com/group/ansible-devel>`_
|
||||
Have a question? Stop by the google group!
|
||||
`irc.freenode.net <http://irc.freenode.net>`_
|
||||
#ansible IRC chat channel
|
||||
|
||||
|
||||
Loading…
Reference in New Issue