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Add filter docs (#2680)

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* Began with filter docs.

* Add more filters.

* Add time unit filters.

* Add TOC and filters to create identifiers.

* Add more filters.

* Add documentation from ansible/ansible for json_query and random_mac.

* Update docs/docsite/rst/filter_guide.rst

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>
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---
sections:
- title: Guides
toctree:
- filter_guide

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.. _ansible_collections.community.general.docsite.filter_guide:
community.general Filter Guide
==============================
The :ref:`community.general collection <plugins_in_community.general>` offers several useful filter plugins.
.. contents:: Topics
Paths
-----
The ``path_join`` filter has been added in ansible-base 2.10. If you want to use this filter, but also need to support Ansible 2.9, you can use ``community.general``'s ``path_join`` shim, ``community.general.path_join``. This filter redirects to ``path_join`` for ansible-base 2.10 and ansible-core 2.11 or newer, and re-implements the filter for Ansible 2.9.
.. code-block:: yaml+jinja
# ansible-base 2.10 or newer:
path: {{ ('/etc', path, 'subdir', file) | path_join }}
# Also works with Ansible 2.9:
path: {{ ('/etc', path, 'subdir', file) | community.general.path_join }}
.. versionadded:: 3.0.0
Abstract transformations
------------------------
Dictionaries
^^^^^^^^^^^^
You can use the ``dict_kv`` filter to create a single-entry dictionary with ``value | community.general.dict_kv(key)``:
.. code-block:: yaml+jinja
- name: Create a single-entry dictionary
debug:
msg: "{{ myvar | community.general.dict_kv('thatsmyvar') }}"
vars:
myvar: myvalue
- name: Create a list of dictionaries where the 'server' field is taken from a list
debug:
msg: >-
{{ myservers | map('community.general.dict_kv', 'server')
| map('combine', common_config) }}
vars:
common_config:
type: host
database: all
myservers:
- server1
- server2
This produces:
.. code-block:: ansible-output
TASK [Create a single-entry dictionary] **************************************************
ok: [localhost] => {
"msg": {
"thatsmyvar": "myvalue"
}
}
TASK [Create a list of dictionaries where the 'server' field is taken from a list] *******
ok: [localhost] => {
"msg": [
{
"database": "all",
"server": "server1",
"type": "host"
},
{
"database": "all",
"server": "server2",
"type": "host"
}
]
}
.. versionadded:: 2.0.0
If you need to convert a list of key-value pairs to a dictionary, you can use the ``dict`` function. Unfortunately, this function cannot be used with ``map``. For this, the ``community.general.dict`` filter can be used:
.. code-block:: yaml+jinja
- name: Create a dictionary with the dict function
debug:
msg: "{{ dict([[1, 2], ['a', 'b']]) }}"
- name: Create a dictionary with the community.general.dict filter
debug:
msg: "{{ [[1, 2], ['a', 'b']] | community.general.dict }}"
- name: Create a list of dictionaries with map and the community.general.dict filter
debug:
msg: >-
{{ values | map('zip', ['k1', 'k2', 'k3'])
| map('map', 'reverse')
| map('community.general.dict') }}
vars:
values:
- - foo
- 23
- a
- - bar
- 42
- b
This produces:
.. code-block:: ansible-output
TASK [Create a dictionary with the dict function] ****************************************
ok: [localhost] => {
"msg": {
"1": 2,
"a": "b"
}
}
TASK [Create a dictionary with the community.general.dict filter] ************************
ok: [localhost] => {
"msg": {
"1": 2,
"a": "b"
}
}
TASK [Create a list of dictionaries with map and the community.general.dict filter] ******
ok: [localhost] => {
"msg": [
{
"k1": "foo",
"k2": 23,
"k3": "a"
},
{
"k1": "bar",
"k2": 42,
"k3": "b"
}
]
}
.. versionadded:: 3.0.0
Grouping
^^^^^^^^
If you have a list of dictionaries, the Jinja2 ``groupby`` filter allows to group the list by an attribute. This results in a list of ``(grouper, list)`` namedtuples, where ``list`` contains all dictionaries where the selected attribute equals ``grouper``. If you know that for every ``grouper``, there will be a most one entry in that list, you can use the ``community.general.groupby_as_dict`` filter to convert the original list into a dictionary which maps ``grouper`` to the corresponding dictionary.
One example is ``ansible_facts.mounts``, which is a list of dictionaries where each has one ``device`` element to indicate the device which is mounted. Therefore, ``ansible_facts.mounts | community.general.groupby_as_dict('device')`` is a dictionary mapping a device to the mount information:
.. code-block:: yaml+jinja
- name: Output mount facts grouped by device name
debug:
var: ansible_facts.mounts | community.general.groupby_as_dict('device')
- name: Output mount facts grouped by mount point
debug:
var: ansible_facts.mounts | community.general.groupby_as_dict('mount')
This produces:
.. code-block:: ansible-output
TASK [Output mount facts grouped by device name] ******************************************
ok: [localhost] => {
"ansible_facts.mounts | community.general.groupby_as_dict('device')": {
"/dev/sda1": {
"block_available": 2000,
"block_size": 4096,
"block_total": 2345,
"block_used": 345,
"device": "/dev/sda1",
"fstype": "ext4",
"inode_available": 500,
"inode_total": 512,
"inode_used": 12,
"mount": "/boot",
"options": "rw,relatime,data=ordered",
"size_available": 56821,
"size_total": 543210,
"uuid": "ab31cade-d9c1-484d-8482-8a4cbee5241a"
},
"/dev/sda2": {
"block_available": 1234,
"block_size": 4096,
"block_total": 12345,
"block_used": 11111,
"device": "/dev/sda2",
"fstype": "ext4",
"inode_available": 1111,
"inode_total": 1234,
"inode_used": 123,
"mount": "/",
"options": "rw,relatime",
"size_available": 42143,
"size_total": 543210,
"uuid": "abcdef01-2345-6789-0abc-def012345678"
}
}
}
TASK [Output mount facts grouped by mount point] ******************************************
ok: [localhost] => {
"ansible_facts.mounts | community.general.groupby_as_dict('mount')": {
"/": {
"block_available": 1234,
"block_size": 4096,
"block_total": 12345,
"block_used": 11111,
"device": "/dev/sda2",
"fstype": "ext4",
"inode_available": 1111,
"inode_total": 1234,
"inode_used": 123,
"mount": "/",
"options": "rw,relatime",
"size_available": 42143,
"size_total": 543210,
"uuid": "bdf50b7d-4859-40af-8665-c637ee7a7808"
},
"/boot": {
"block_available": 2000,
"block_size": 4096,
"block_total": 2345,
"block_used": 345,
"device": "/dev/sda1",
"fstype": "ext4",
"inode_available": 500,
"inode_total": 512,
"inode_used": 12,
"mount": "/boot",
"options": "rw,relatime,data=ordered",
"size_available": 56821,
"size_total": 543210,
"uuid": "ab31cade-d9c1-484d-8482-8a4cbee5241a"
}
}
}
.. versionadded: 3.0.0
Merging lists of dictionaries
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
If you have two lists of dictionaries and want to combine them into a list of merged dictionaries, where two dictionaries are merged if they coincide in one attribute, you can use the ``lists_mergeby`` filter.
.. code-block:: yaml+jinja
- name: Merge two lists by common attribute 'name'
debug:
var: list1 | community.general.lists_mergeby(list2, 'name')
vars:
list1:
- name: foo
extra: true
- name: bar
extra: false
- name: meh
extra: true
list2:
- name: foo
path: /foo
- name: baz
path: /bazzz
This produces:
.. code-block:: ansible-output
TASK [Merge two lists by common attribute 'name'] ****************************************
ok: [localhost] => {
"list1 | community.general.lists_mergeby(list2, 'name')": [
{
"extra": false,
"name": "bar"
},
{
"name": "baz",
"path": "/bazzz"
},
{
"extra": true,
"name": "foo",
"path": "/foo"
},
{
"extra": true,
"name": "meh"
}
]
}
.. versionadded: 2.0.0
Working with times
------------------
The ``to_time_unit`` filter allows to convert times from a human-readable string to a unit. For example, ``'4h 30min 12second' | community.general.to_time_unit('hour')`` gives the number of hours that correspond to 4 hours, 30 minutes and 12 seconds.
There are shorthands to directly convert to various units, like ``to_hours``, ``to_minutes``, ``to_seconds``, and so on. The following table lists all units that can be used:
.. list-table:: Units
:widths: 25 25 25 25
:header-rows: 1
* - Unit name
- Unit value in seconds
- Unit strings for filter
- Shorthand filter
* - Millisecond
- 1/1000 second
- ``ms``, ``millisecond``, ``milliseconds``, ``msec``, ``msecs``, ``msecond``, ``mseconds``
- ``to_milliseconds``
* - Second
- 1 second
- ``s``, ``sec``, ``secs``, ``second``, ``seconds``
- ``to_seconds``
* - Minute
- 60 seconds
- ``m``, ``min``, ``mins``, ``minute``, ``minutes``
- ``to_minutes``
* - Hour
- 60*60 seconds
- ``h``, ``hour``, ``hours``
- ``to_hours``
* - Day
- 24*60*60 seconds
- ``d``, ``day``, ``days``
- ``to_days``
* - Week
- 7*24*60*60 seconds
- ``w``, ``week``, ``weeks``
- ``to_weeks``
* - Month
- 30*24*60*60 seconds
- ``mo``, ``month``, ``months``
- ``to_months``
* - Year
- 365*24*60*60 seconds
- ``y``, ``year``, ``years``
- ``to_years``
Note that months and years are using a simplified representation: a month is 30 days, and a year is 365 days. If you need different definitions of months or years, you can pass them as keyword arguments. For example, if you want a year to be 365.25 days, and a month to be 30.5 days, you can write ``'11months 4' | community.general.to_years(year=365.25, month=30.5)``. These keyword arguments can be specified to ``to_time_unit`` and to all shorthand filters.
.. code-block:: yaml+jinja
- name: Convert string to seconds
debug:
msg: "{{ '30h 20m 10s 123ms' | community.general.to_time_unit('seconds') }}"
- name: Convert string to hours
debug:
msg: "{{ '30h 20m 10s 123ms' | community.general.to_hours }}"
- name: Convert string to years (using 365.25 days == 1 year)
debug:
msg: "{{ '400d 15h' | community.general.to_years(year=365.25) }}"
This produces:
.. code-block:: ansible-output
TASK [Convert string to seconds] **********************************************************
ok: [localhost] => {
"msg": "109210.123"
}
TASK [Convert string to hours] ************************************************************
ok: [localhost] => {
"msg": "30.336145277778"
}
TASK [Convert string to years (using 365.25 days == 1 year)] ******************************
ok: [localhost] => {
"msg": "1.096851471595"
}
.. versionadded: 0.2.0
Working with versions
---------------------
If you need to sort a list of version numbers, the Jinja ``sort`` filter is problematic. Since it sorts lexicographically, ``2.10`` will come before ``2.9``. To treat version numbers correctly, you can use the ``version_sort`` filter:
.. code-block:: yaml+jinja
- name: Sort list by version number
debug:
var: ansible_versions | community.general.version_sort
vars:
ansible_versions:
- '2.8.0'
- '2.11.0'
- '2.7.0'
- '2.10.0'
- '2.9.0'
This produces:
.. code-block:: ansible-output
TASK [Sort list by version number] ********************************************************
ok: [localhost] => {
"ansible_versions | community.general.version_sort": [
"2.7.0",
"2.8.0",
"2.9.0",
"2.10.0",
"2.11.0"
]
}
.. versionadded: 2.2.0
Creating identifiers
--------------------
The following filters allow to create identifiers.
Hashids
^^^^^^^
`Hashids <https://hashids.org/>`_ allow to convert sequences of integers to short unique string identifiers. This filter needs the `hashids Python library <https://pypi.org/project/hashids/>`_ installed on the controller.
.. code-block:: yaml+jinja
- name: "Create hashid"
debug:
msg: "{{ [1234, 5, 6] | community.general.hashids_encode }}"
- name: "Decode hashid"
debug:
msg: "{{ 'jm2Cytn' | community.general.hashids_decode }}"
This produces:
.. code-block:: ansible-output
TASK [Create hashid] **********************************************************************
ok: [localhost] => {
"msg": "jm2Cytn"
}
TASK [Decode hashid] **********************************************************************
ok: [localhost] => {
"msg": [
1234,
5,
6
]
}
The hashids filters accept keyword arguments to allow fine-tuning the hashids generated:
:salt: String to use as salt when hashing.
:alphabet: String of 16 or more unique characters to produce a hash.
:min_length: Minimum length of hash produced.
.. versionadded: 3.0.0
Random MACs
^^^^^^^^^^^
You can use the ``random_mac`` filter to complete a partial `MAC address <https://en.wikipedia.org/wiki/MAC_address>`_ to a random 6-byte MAC address.
.. code-block:: yaml+jinja
- name: "Create a random MAC starting with ff:"
debug:
msg: "{{ 'FF' | community.general.random_mac }}"
- name: "Create a random MAC starting with 00:11:22:"
debug:
msg: "{{ '00:11:22' | community.general.random_mac }}"
This produces:
.. code-block:: ansible-output
TASK [Create a random MAC starting with ff:] **********************************************
ok: [localhost] => {
"msg": "ff:69:d3:78:7f:b4"
}
TASK [Create a random MAC starting with 00:11:22:] ****************************************
ok: [localhost] => {
"msg": "00:11:22:71:5d:3b"
}
You can also initialize the random number generator from a seed to create random-but-idempotent MAC addresses:
.. code-block:: yaml+jinja
"{{ '52:54:00' | community.general.random_mac(seed=inventory_hostname) }}"
Conversions
-----------
Parsing CSV files
^^^^^^^^^^^^^^^^^
Ansible offers the :ref:`community.general.read_csv module <ansible_collections.community.general.read_csv_module>` to read CSV files. Sometimes you need to convert strings to CSV files instead. For this, the ``from_csv`` filter exists.
.. code-block:: yaml+jinja
- name: "Parse CSV from string"
debug:
msg: "{{ csv_string | community.general.from_csv }}"
vars:
csv_string: |
foo,bar,baz
1,2,3
you,this,then
This produces:
.. code-block:: ansible-output
TASK [Parse CSV from string] **************************************************************
ok: [localhost] => {
"msg": [
{
"bar": "2",
"baz": "3",
"foo": "1"
},
{
"bar": "this",
"baz": "then",
"foo": "you"
}
]
}
The ``from_csv`` filter has several keyword arguments to control its behavior:
:dialect: Dialect of the CSV file. Default is ``excel``. Other possible choices are ``excel-tab`` and ``unix``. If one of ``delimiter``, ``skipinitialspace`` or ``strict`` is specified, ``dialect`` is ignored.
:fieldnames: A set of column names to use. If not provided, the first line of the CSV is assumed to contain the column names.
:delimiter: Sets the delimiter to use. Default depends on the dialect used.
:skipinitialspace: Set to ``true`` to ignore space directly after the delimiter. Default depends on the dialect used (usually ``false``).
:strict: Set to ``true`` to error out on invalid CSV input.
.. versionadded: 3.0.0
Converting to JSON
^^^^^^^^^^^^^^^^^^
`JC <https://pypi.org/project/jc/>`_ is a CLI tool and Python library which allows to interpret output of various CLI programs as JSON. It is also available as a filter in community.general. This filter needs the `jc Python library <https://pypi.org/project/jc/>`_ installed on the controller.
.. code-block:: yaml+jinja
- name: Run 'ls' to list files in /
command: ls /
register: result
- name: Parse the ls output
debug:
msg: "{{ result.stdout | community.general.jc('ls') }}"
This produces:
.. code-block:: ansible-output
TASK [Run 'ls' to list files in /] ********************************************************
changed: [localhost]
TASK [Parse the ls output] ****************************************************************
ok: [localhost] => {
"msg": [
{
"filename": "bin"
},
{
"filename": "boot"
},
{
"filename": "dev"
},
{
"filename": "etc"
},
{
"filename": "home"
},
{
"filename": "lib"
},
{
"filename": "proc"
},
{
"filename": "root"
},
{
"filename": "run"
},
{
"filename": "tmp"
}
]
}
.. versionadded: 2.0.0
.. _ansible_collections.community.general.docsite.json_query_filter:
Selecting JSON data: JSON queries
---------------------------------
To select a single element or a data subset from a complex data structure in JSON format (for example, Ansible facts), use the ``json_query`` filter. The ``json_query`` filter lets you query a complex JSON structure and iterate over it using a loop structure.
.. note:: You must manually install the **jmespath** dependency on the Ansible controller before using this filter. This filter is built upon **jmespath**, and you can use the same syntax. For examples, see `jmespath examples <http://jmespath.org/examples.html>`_.
Consider this data structure:
.. code-block:: yaml+jinja
{
"domain_definition": {
"domain": {
"cluster": [
{
"name": "cluster1"
},
{
"name": "cluster2"
}
],
"server": [
{
"name": "server11",
"cluster": "cluster1",
"port": "8080"
},
{
"name": "server12",
"cluster": "cluster1",
"port": "8090"
},
{
"name": "server21",
"cluster": "cluster2",
"port": "9080"
},
{
"name": "server22",
"cluster": "cluster2",
"port": "9090"
}
],
"library": [
{
"name": "lib1",
"target": "cluster1"
},
{
"name": "lib2",
"target": "cluster2"
}
]
}
}
}
To extract all clusters from this structure, you can use the following query:
.. code-block:: yaml+jinja
- name: Display all cluster names
ansible.builtin.debug:
var: item
loop: "{{ domain_definition | community.general.json_query('domain.cluster[*].name') }}"
To extract all server names:
.. code-block:: yaml+jinja
- name: Display all server names
ansible.builtin.debug:
var: item
loop: "{{ domain_definition | community.general.json_query('domain.server[*].name') }}"
To extract ports from cluster1:
.. code-block:: yaml+jinja
- name: Display all ports from cluster1
ansible.builtin.debug:
var: item
loop: "{{ domain_definition | community.general.json_query(server_name_cluster1_query) }}"
vars:
server_name_cluster1_query: "domain.server[?cluster=='cluster1'].port"
.. note:: You can use a variable to make the query more readable.
To print out the ports from cluster1 in a comma separated string:
.. code-block:: yaml+jinja
- name: Display all ports from cluster1 as a string
ansible.builtin.debug:
msg: "{{ domain_definition | community.general.json_query('domain.server[?cluster==`cluster1`].port') | join(', ') }}"
.. note:: In the example above, quoting literals using backticks avoids escaping quotes and maintains readability.
You can use YAML `single quote escaping <https://yaml.org/spec/current.html#id2534365>`_:
.. code-block:: yaml+jinja
- name: Display all ports from cluster1
ansible.builtin.debug:
var: item
loop: "{{ domain_definition | community.general.json_query('domain.server[?cluster==''cluster1''].port') }}"
.. note:: Escaping single quotes within single quotes in YAML is done by doubling the single quote.
To get a hash map with all ports and names of a cluster:
.. code-block:: yaml+jinja
- name: Display all server ports and names from cluster1
ansible.builtin.debug:
var: item
loop: "{{ domain_definition | community.general.json_query(server_name_cluster1_query) }}"
vars:
server_name_cluster1_query: "domain.server[?cluster=='cluster2'].{name: name, port: port}"
To extract ports from all clusters with name starting with 'server1':
.. code-block:: yaml+jinja
- name: Display all ports from cluster1
ansible.builtin.debug:
msg: "{{ domain_definition | to_json | from_json | community.general.json_query(server_name_query) }}"
vars:
server_name_query: "domain.server[?starts_with(name,'server1')].port"
To extract ports from all clusters with name containing 'server1':
.. code-block:: yaml+jinja
- name: Display all ports from cluster1
ansible.builtin.debug:
msg: "{{ domain_definition | to_json | from_json | community.general.json_query(server_name_query) }}"
vars:
server_name_query: "domain.server[?contains(name,'server1')].port"
.. note:: while using ``starts_with`` and ``contains``, you have to use `` to_json | from_json `` filter for correct parsing of data structure.