1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
.. _lookup_plugins:
Lookup Plugins
==============
.. contents::
:local:
:depth: 2
Lookup plugins are an Ansible-specific extension to the Jinja2 templating language. You can use lookup plugins to access data from outside sources (files, databases, key/value stores, APIs, and other services) within your playbooks. Like all :ref:`templating <playbooks_templating>`, lookups execute and are evaluated on the Ansible control machine. Ansible makes the data returned by a lookup plugin available using the standard templating system. You can use lookup plugins to load variables or templates with information from external sources.
.. 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.
- Pass ``wantlist=True`` to lookups to use in Jinja2 template "for" loops.
.. 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
-----------------------
Ansible enables all lookup plugins it can find. You can activate a custom lookup by either dropping it into a ``lookup_plugins`` directory adjacent to your play, inside the ``plugins/lookup/`` directory of a collection you have installed, inside a standalone role, or in one of the lookup directory sources configured in :ref:`ansible.cfg <ansible_configuration_settings>`.
.. _using_lookup:
Using lookup plugins
--------------------
You can use lookup plugins 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+Jinja
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. For this reason, most lookups output lists and take lists as input; for example, ``with_items`` uses the :ref:`items <items_lookup>` lookup::
tasks:
- name: count to 3
debug: msg={{item}}
with_items: [1, 2, 3]
You can combine lookups with :ref:`filters <playbooks_filters>`, :ref:`tests <playbooks_tests>` and even each other to do some complex data generation and manipulation. For example::
tasks:
- name: valid but useless and over complicated chained lookups and filters
debug: msg="find the answer here:\n{{ lookup('url', 'https://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:: 2.6
You can 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 if the lookup returns an error. For example:
To ignore lookup errors::
- name: if this file does not exist, I do not care .. file plugin itself warns anyway ...
debug: msg="{{ lookup('file', '/nosuchfile', errors='ignore') }}"
.. code-block:: ansible-output
[WARNING]: Unable to find '/nosuchfile' in expected paths (use -vvvvv to see paths)
ok: [localhost] => {
"msg": ""
}
To get a warning instead of a failure::
- name: if this file does not exist, let me know, but continue
debug: msg="{{ lookup('file', '/nosuchfile', errors='warn') }}"
.. code-block:: ansible-output
[WARNING]: Unable to find '/nosuchfile' 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: /nosuchfile
ok: [localhost] => {
"msg": ""
}
To get a fatal error (the default)::
- name: if this file does not exist, FAIL (this is the default)
debug: msg="{{ lookup('file', '/nosuchfile', errors='strict') }}"
.. code-block:: ansible-output
[WARNING]: Unable to find '/nosuchfile' 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: /nosuchfile"}
.. _query:
Forcing lookups to return lists: ``query`` and ``wantlist=True``
----------------------------------------------------------------
.. 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 feature provides an easier and more consistent interface for interacting with the new ``loop`` keyword, while maintaining backwards compatibility with other uses of ``lookup``.
The following examples are equivalent:
.. code-block:: jinja
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``:
.. code-block:: jinja
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.
.. seealso::
:ref:`about_playbooks`
An introduction to playbooks
:ref:`inventory_plugins`
Ansible inventory plugins
:ref:`callback_plugins`
Ansible callback plugins
:ref:`playbooks_filters`
Jinja2 filter plugins
:ref:`playbooks_tests`
Jinja2 test plugins
:ref:`playbooks_lookups`
Jinja2 lookup plugins
`User Mailing List <https://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
|
