mirror of
https://github.com/ansible-collections/community.general.git
synced 2024-09-14 20:13:21 +02:00
163 lines
6 KiB
ReStructuredText
163 lines
6 KiB
ReStructuredText
.. contents:: Topics
|
|
|
|
|
|
Lookup Plugins
|
|
--------------
|
|
|
|
Lookup plugins allow Ansible to access data from outside sources.
|
|
This can include reading the filesystem in addition to contacting external datastores and services.
|
|
Like all templating, these plugins are evaluated on the Ansible control machine, not on the target/remote.
|
|
|
|
The data returned by a lookup plugin is made available using the standard templating system in Ansible,
|
|
and are typically used to load variables or templates with information from those systems.
|
|
|
|
Lookups are an Ansible-specific extension to the Jinja2 templating language.
|
|
|
|
.. note::
|
|
- Lookups are executed with a working directory relative to the role or play,
|
|
as opposed to local tasks, which are executed relative the executed script.
|
|
- Since Ansible version 1.9, you can pass wantlist=True to lookups to use in Jinja2 template "for" loops.
|
|
- Lookup plugins are an advanced feature; to best leverage them you should have a good working knowledge of how to use Ansible plays.
|
|
|
|
.. warning::
|
|
- Some lookups pass arguments to a shell. When using variables from a remote/untrusted source, use the `|quote` filter to ensure safe usage.
|
|
|
|
|
|
.. _enabling_lookup:
|
|
|
|
Enabling Lookup Plugins
|
|
+++++++++++++++++++++++
|
|
|
|
You can activate a custom lookup by either dropping it into a ``lookup_plugins`` directory adjacent to your play, inside a role, or by putting it in one of the lookup directory sources configured in :ref:`ansible.cfg <ansible_configuration_settings>`.
|
|
|
|
|
|
.. _using_lookup:
|
|
|
|
Using Lookup Plugins
|
|
++++++++++++++++++++
|
|
|
|
Lookup plugins can be used anywhere you can use templating in Ansible: in a play, in variables file, or in a Jinja2 template for the :ref:`template <template_module>` module.
|
|
|
|
.. code-block:: yaml
|
|
|
|
vars:
|
|
file_contents: "{{lookup('file', 'path/to/file.txt')}}"
|
|
|
|
Lookups are an integral part of loops. Wherever you see ``with_``, the part after the underscore is the name of a lookup.
|
|
This is also the reason most lookups output lists and take lists as input; for example, ``with_items`` uses the :doc:`items <lookup/items>` lookup:
|
|
|
|
.. code-block:: yaml
|
|
|
|
tasks:
|
|
- name: count to 3
|
|
debug: msg={{item}}
|
|
with_items: [1, 2, 3]
|
|
|
|
You can combine lookups with :ref:`playbooks_filters`, :ref:`playbooks_tests` and even each other to do some complex data generation and manipulation. For example:
|
|
|
|
.. code-block:: yaml
|
|
|
|
tasks:
|
|
- name: valid but useless and over complicated chained lookups and filters
|
|
debug: msg="find the answer here:\n{{ lookup('url', 'http://google.com/search/?q=' + item|urlencode)|join(' ') }}"
|
|
with_nested:
|
|
- "{{lookup('consul_kv', 'bcs/' + lookup('file', '/the/question') + ', host=localhost, port=2000')|shuffle}}"
|
|
- "{{lookup('sequence', 'end=42 start=2 step=2')|map('log', 4)|list)}}"
|
|
- ['a', 'c', 'd', 'c']
|
|
|
|
.. versionadded:: 2.5
|
|
|
|
You can now control how errors behave in all lookup plugins by setting ``errors`` to ``ignore``, ``warn``, or ``strict``. The default setting is ``strict``, which causes the task to fail. For example:
|
|
|
|
To ignore errors::
|
|
|
|
- name: file doesnt exist, but i dont care .. file plugin itself warns anyways ...
|
|
debug: msg="{{ lookup('file', '/idontexist', errors='ignore') }}"
|
|
|
|
[WARNING]: Unable to find '/idontexist' in expected paths (use -vvvvv to see paths)
|
|
|
|
ok: [localhost] => {
|
|
"msg": ""
|
|
}
|
|
|
|
|
|
To get a warning instead of a failure::
|
|
|
|
- name: file doesnt exist, let me know, but continue
|
|
debug: msg="{{ lookup('file', '/idontexist', errors='warn') }}"
|
|
|
|
[WARNING]: Unable to find '/idontexist' in expected paths (use -vvvvv to see paths)
|
|
|
|
[WARNING]: An unhandled exception occurred while running the lookup plugin 'file'. Error was a <class 'ansible.errors.AnsibleError'>, original message: could not locate file in lookup: /idontexist
|
|
|
|
ok: [localhost] => {
|
|
"msg": ""
|
|
}
|
|
|
|
|
|
Fatal error (the default)::
|
|
|
|
- name: file doesnt exist, FAIL (this is the default)
|
|
debug: msg="{{ lookup('file', '/idontexist', errors='strict') }}"
|
|
|
|
[WARNING]: Unable to find '/idontexist' in expected paths (use -vvvvv to see paths)
|
|
|
|
fatal: [localhost]: FAILED! => {"msg": "An unhandled exception occurred while running the lookup plugin 'file'. Error was a <class 'ansible.errors.AnsibleError'>, original message: could not locate file in lookup: /idontexist"}
|
|
|
|
|
|
.. _query:
|
|
|
|
query
|
|
+++++
|
|
|
|
.. versionadded:: 2.5
|
|
|
|
In Ansible 2.5, a new jinja2 function called ``query`` was added for invoking lookup plugins. The difference between ``lookup`` and ``query`` is largely that ``query`` will always return a list.
|
|
The default behavior of ``lookup`` is to return a string of comma separated values. ``lookup`` can be explicitly configured to return a list using ``wantlist=True``.
|
|
|
|
This was done primarily to provide an easier and more consistent interface for interacting with the new ``loop`` keyword, while maintaining backwards compatibiltiy with other uses of ``lookup``.
|
|
|
|
The following examples are equivalent::
|
|
|
|
lookup('dict', dict_variable, wantlist=True)
|
|
|
|
query('dict', dict_variable)
|
|
|
|
As demonstrated above the behavior of ``wantlist=True`` is implicit when using ``query``.
|
|
|
|
Additionally, ``q`` was introduced as a shortform of ``query``::
|
|
|
|
q('dict', dict_variable)
|
|
|
|
|
|
.. _lookup_plugins_list:
|
|
|
|
Plugin List
|
|
+++++++++++
|
|
|
|
You can use ``ansible-doc -t lookup -l`` to see the list of available plugins. Use ``ansible-doc -t lookup <plugin name>`` to see specific documents and examples.
|
|
|
|
|
|
.. toctree:: :maxdepth: 1
|
|
:glob:
|
|
|
|
lookup/*
|
|
|
|
.. seealso::
|
|
|
|
:ref:`about_playbooks`
|
|
An introduction to playbooks
|
|
:doc:`inventory`
|
|
Ansible inventory plugins
|
|
:doc:`callback`
|
|
Ansible callback plugins
|
|
:ref:`playbooks_filters`
|
|
Jinja2 filter plugins
|
|
:ref:`playbooks_tests`
|
|
Jinja2 test plugins
|
|
:ref:`playbooks_lookups`
|
|
Jinja2 lookup plugins
|
|
`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
|