.. _requisites:

===========================================
Requisites and Other Global State Arguments
===========================================

Requisites
==========

The Salt requisite system is used to create relationships between states. This
provides a method to easily define inter-dependencies between states. These
dependencies are expressed by declaring the relationships using state names
and IDs or names. The generalized form of a requisite target is ``<state name>:
<ID or name>``. The specific form is defined as a :ref:`Requisite Reference
<requisite-reference>`.

A common use-case for requisites is ensuring a package has been installed before
trying to ensure the service is running. In the following example, Salt will
ensure nginx has been installed before trying to manage the service. If the
package could not be installed, Salt will not try to manage the service.

.. code-block:: yaml

    nginx:
      pkg.installed:
        - name: nginx-light
      service.running:
        - enable: True
        - require:
          - pkg: nginx

Without the requisite defined, salt would attempt to install the package and
then attempt to manage the service even if the installation failed.

These requisites always form dependencies in a predictable single direction.
Each requisite has an alternate :ref:`<requisite>_in <requisites-in>` form that
can be used to establish a "reverse" dependency--useful in for loops.

In the end, a single dependency map is created and everything is executed in a
finite and predictable order.

.. _requisites-matching:

Requisite matching
------------------

Requisites typically need two pieces of information for matching:

* The state module name (e.g. ``pkg`` or ``service``)
* The state identifier (e.g. ``nginx`` or ``/etc/nginx/nginx.conf``)

.. code-block:: yaml

    nginx:
      pkg.installed: []
      file.managed:
        - name: /etc/nginx/nginx.conf
      service.running:
        - require:
          - pkg: nginx
          - file: /etc/nginx/nginx.conf

Glob matching in requisites
~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. versionadded:: 0.9.8

Glob matching is supported in requisites. This is mostly useful for file
changes. In the example below, a change in ``/etc/apache2/httpd.conf`` or
``/etc/apache2/sites-available/default.conf`` will reload/restart the service:

.. code-block:: yaml

    apache2:
      service.running:
        - watch:
          - file: /etc/apache2/*

Omitting state module in requisites
-----------------------------------

.. versionadded:: 2016.3.0

In version 2016.3.0, the state module name was made optional. If the state module
is omitted, all states matching the ID will be required, regardless of which
module they are using.

.. code-block:: yaml

    - require:
      - vim

State target matching
~~~~~~~~~~~~~~~~~~~~~

In order to understand how state targets are matched, it is helpful to know
:ref:`how the state compiler is working <compiler-ordering>`. Consider the following
example:

.. code-block:: yaml

    Deploy server package:
      file.managed:
        - name: /usr/local/share/myapp.tar.xz
        - source: salt://myapp.tar.xz

    Extract server package:
      archive.extracted:
        - name: /usr/local/share/myapp
        - source: /usr/local/share/myapp.tar.xz
        - archive_format: tar
        - onchanges:
          - file: Deploy server package

The first formula is converted to a dictionary which looks as follows (represented
as YAML, some properties omitted for simplicity) as `High Data`:

.. code-block:: yaml

    Deploy server package:
      file:
        - managed
        - name: /usr/local/share/myapp.tar.xz
        - source: salt://myapp.tar.xz

The ``file.managed`` format used in the formula is essentially syntactic sugar:
at the end, the target is ``file``, which is used in the ``Extract server package``
state above.

Identifier matching
~~~~~~~~~~~~~~~~~~~

Requisites match on both the ID Declaration and the ``name`` parameter.
This means that, in the "Deploy server package" example above, a ``require``
requisite would match with ``Deploy server package`` *or* ``/usr/local/share/myapp.tar.xz``,
so either of the following versions for "Extract server package" is correct:

.. code-block:: yaml

    # (Archive arguments omitted for simplicity)

    # Match by ID declaration
    Extract server package:
      archive.extracted:
        - onchanges:
          - file: Deploy server package

    # Match by name parameter
    Extract server package:
      archive.extracted:
        - onchanges:
          - file: /usr/local/share/myapp.tar.xz

Omitting state module in requisites
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. versionadded:: 2016.3.0

In version 2016.3.0, the state module name was made optional. If the state module
is omitted, all states matching the ID will be required, regardless of which
module they are using.

.. code-block:: yaml

    - require:
      - vim

Requisites Types
----------------

All requisite types have a corresponding :ref:`<requisite>_in <requisites-in>` form:

* :ref:`require <requisites-require>`: Requires that a list of target states succeed before execution
* :ref:`onchanges <requisites-onchanges>`: Execute if any target states succeed with changes
* :ref:`watch <requisites-watch>`: Similar to ``onchanges``; modifies state behavior using ``mod_watch``
* :ref:`listen <requisites-listen>`: Similar to ``onchanges``; delays execution to end of state run using ``mod_wait``
* :ref:`prereq <requisites-prereq>`: Execute prior to target state if target state expects to produce changes
* :ref:`onfail <requisites-onfail>`: Execute only if a target state fails
* :ref:`use <requisites-use>`: Copy arguments from another state

Several requisite types have a corresponding :ref:`requisite_any <requisites-any>` form:

* ``require_any``
* ``watch_any``
* ``onchanges_any``
* ``onfail_any``

Lastly, onfail has one special ``onfail_all`` form to account for when `AND`
logic is desired instead of the default `OR` logic of onfail/onfail_any (which
are equivalent).

All requisites define specific relationships and always work with the dependency
logic defined :ref:`above <requisites-matching>`.

.. _requisites-require:

require
~~~~~~~

The use of ``require`` builds a dependency that prevents a state from executing
until all required states execute successfully. If any required state fails,
then the state will fail due to requisites.

In the following example, the ``service`` state will not be checked unless both
``file`` states execute without failure.

.. code-block:: yaml

    nginx:
      service.running:
        - require:
          - file: /etc/nginx/nginx.conf
          - file: /etc/nginx/conf.d/ssl.conf

Require SLS File
++++++++++++++++

As of Salt 0.16.0, it is possible to require an entire sls file. Do this by first
including the sls file and then setting a state to ``require`` the included sls
file:

.. code-block:: yaml

    include:
      - foo

    bar:
      pkg.installed:
        - require:
          - sls: foo

This will add a ``require`` to all of the state declarations found in the given
sls file. This means that ``bar`` will ``require`` every state within ``foo``.
This makes it very easy to batch large groups of states easily in any requisite
statement.

.. _requisites-onchanges:

onchanges
~~~~~~~~~

.. versionadded:: 2014.7.0

The ``onchanges`` requisite makes a state only apply if the required states
generate changes, and if the watched state's "result" is ``True`` (does not fail).
This can be a useful way to execute a post hook after changing aspects of a system.

If a state has multiple ``onchanges`` requisites then the state will trigger
if any of the watched states changes.

.. code-block:: yaml

    myservice:
      file.managed:
        - name: /etc/myservice/myservice.conf
        - source: salt://myservice/files/myservice.conf
      cmd.run:
        - name: /usr/local/sbin/run-build
        - onchanges:
          - file: /etc/myservice/myservice.conf

In the example above, ``cmd.run`` will run only if there are changes in the
``file.managed`` state.

An easy mistake to make is using ``onchanges_in`` when ``onchanges`` is the
correct choice, as seen in this next example.

.. code-block:: yaml

    myservice:
      file.managed:
        - name: /etc/myservice/myservice.conf
        - source: salt://myservice/files/myservice.conf
      cmd.run:
        - name: /usr/local/sbin/run-build
        - onchanges_in:  # <-- broken logic
          - file: /etc/myservice/myservice.conf


This will set up a requisite relationship in which the ``cmd.run`` state
always executes, and the ``file.managed`` state only executes if the
``cmd.run`` state has changes (which it always will, since the ``cmd.run``
state includes the command results as changes).

It may semantically seem like the ``cmd.run`` state should only run
when there are changes in the file state, but remember that requisite
relationships involve one state watching another state, and a
:ref:`requisite_in <requisites-onchanges-in>` does the opposite: it forces
the specified state to watch the state with the ``requisite_in``.

.. _requisites-watch:

watch
~~~~~

A ``watch`` requisite is used to add additional behavior when there are changes
in other states. This is done using the ``mod_watch`` function available from
the execution module and will execute any time a watched state changes.

.. note::

    If a state should only execute when another state has changes, and
    otherwise do nothing, the ``onchanges`` requisite should be used instead
    of ``watch``. ``watch`` is designed to add *additional* behavior when
    there are changes, but otherwise the state executes normally.

A good example of using ``watch`` is with a :mod:`service.running
<salt.states.service.running>` state. When a service watches a state, then
the service is reloaded/restarted when the watched state changes, in addition
to Salt ensuring that the service is running.

.. code-block:: yaml

    ntpd:
      service.running:
        - watch:
          - file: /etc/ntp.conf
      file.managed:
        - name: /etc/ntp.conf
        - source: salt://ntp/files/ntp.conf

Another useful example of ``watch`` is using salt to ensure a configuration file
is present and in a correct state, ensure the service is running, and trigger
``service nginx reload`` instead of ``service nginx restart`` in order to avoid
dropping any connections.

.. code-block:: yaml

    nginx:
      service.running:
        - reload: True
        - watch:
          - file: nginx
      file.managed:
        - name: /etc/nginx/conf.d/tls-settings.conf
        - source: salt://nginx/files/tls-settings.conf

.. note::

    Not all state modules contain ``mod_watch``. If ``mod_watch`` is absent
    from the watching state module, the ``watch`` requisite behaves exactly
    like a ``require`` requisite.

The state containing the ``watch`` requisite is defined as the watching
state. The state specified in the ``watch`` statement is defined as the watched
state. When the watched state executes, it will return a dictionary containing
a key named "changes". Here are two examples of state return dictionaries,
shown in json for clarity:

.. code-block:: json

    {
        "local": {
            "file_|-/tmp/foo_|-/tmp/foo_|-directory": {
                "comment": "Directory /tmp/foo updated",
                "__run_num__": 0,
                "changes": {
                    "user": "bar"
                },
                "name": "/tmp/foo",
                "result": true
            }
        }
    }

    {
        "local": {
            "pkgrepo_|-salt-minion_|-salt-minion_|-managed": {
                "comment": "Package repo 'salt-minion' already configured",
                "__run_num__": 0,
                "changes": {},
                "name": "salt-minion",
                "result": true
            }
        }
    }

If the "result" of the watched state is ``True``, the watching state *will
execute normally*, and if it is ``False``, the watching state will never run.
This part of ``watch`` mirrors the functionality of the ``require`` requisite.

If the "result" of the watched state is ``True`` *and* the "changes"
key contains a populated dictionary (changes occurred in the watched state),
then the ``watch`` requisite can add additional behavior. This additional
behavior is defined by the ``mod_watch`` function within the watching state
module. If the ``mod_watch`` function exists in the watching state module, it
will be called *in addition to* the normal watching state. The return data
from the ``mod_watch`` function is what will be returned to the master in this
case; the return data from the main watching function is discarded.

If the "changes" key contains an empty dictionary, the ``watch`` requisite acts
exactly like the ``require`` requisite (the watching state will execute if
"result" is ``True``, and fail if "result" is ``False`` in the watched state).

.. note::

   If the watching state ``changes`` key contains values, then ``mod_watch``
   will not be called. If you're using ``watch`` or ``watch_in`` then it's a
   good idea to have a state that only enforces one attribute - such as
   splitting out ``service.running`` into its own state and have
   ``service.enabled`` in another.

One common source of confusion is expecting ``mod_watch`` to be called for
every necessary change. You might be tempted to write something like this:

.. code-block:: yaml

   httpd:
     service.running:
       - enable: True
       - watch:
         - file: httpd-config

   httpd-config:
     file.managed:
       - name: /etc/httpd/conf/httpd.conf
       - source: salt://httpd/files/apache.conf

If your service is already running but not enabled, you might expect that Salt
will be able to tell that since the config file changed your service needs to
be restarted. This is not the case. Because the service needs to be enabled,
that change will be made and ``mod_watch`` will never be triggered. In this
case, changes to your ``apache.conf`` will fail to be loaded. If you want to
ensure that your service always reloads the correct way to handle this is
either ensure that your service is not running before applying your state, or
simply make sure that ``service.running`` is in a state on its own:

.. code-block:: yaml

   enable-httpd:
     service.enabled:
       - name: httpd

   start-httpd:
     service.running:
       - name: httpd
       - watch:
         - file: httpd-config

   httpd-config:
     file.managed:
       - name: /etc/httpd/conf/httpd.conf
       - source: salt://httpd/files/apache.conf

Now that ``service.running`` is its own state, changes to ``service.enabled``
will no longer prevent ``mod_watch`` from getting triggered, so your ``httpd``
service will get restarted like you want.

.. _requisites-listen:

listen
~~~~~~

.. versionadded:: 2014.7.0

A ``listen`` requisite is used to trigger the ``mod_wait`` function of an
execution module. Rather than modifying execution order, the ``mod_wait`` state
created by ``listen`` will execute at the end of the state run.

.. code-block:: yaml

 restart-apache2:
   service.running:
     - name: apache2
     - listen:
       - file: /etc/apache2/apache2.conf

 configure-apache2:
   file.managed:
     - name: /etc/apache2/apache2.conf
     - source: salt://apache2/apache2.conf

This example will cause apache2 to restart when the apache2.conf file is
changed, but the apache2 restart will happen at the end of the state run.

.. code-block:: yaml

 restart-apache2:
   service.running:
     - name: apache2

 configure-apache2:
   file.managed:
     - name: /etc/apache2/apache2.conf
     - source: salt://apache2/apache2.conf
     - listen_in:
       - service: apache2

This example does the same as the above example, but puts the state argument
on the file resource, rather than the service resource.

.. _requisites-prereq:

prereq
~~~~~~

.. versionadded:: 0.16.0

The ``prereq`` requisite works similar to ``onchanges`` except that it uses the
result from ``test=True`` on the observed state to determine if it should run
prior to the observed state being run.

The best way to define how ``prereq`` operates is displayed in the following
practical example: When a service should be shut down because underlying code
is going to change, the service should be off-line while the update occurs. In
this example, ``graceful-down`` is the pre-requiring state and ``site-code``
is the pre-required state.

.. code-block:: yaml

    graceful-down:
      cmd.run:
        - name: service apache graceful
        - prereq:
          - file: site-code

    site-code:
      file.recurse:
        - name: /opt/site_code
        - source: salt://site/code

In this case, the apache server will only be shut down if the site-code state
expects to deploy fresh code via the file.recurse call. The site-code deployment
will only be executed if the graceful-down run completes successfully.

When a ``prereq`` requisite is evaluated, the pre-required state reports if it
expects to have any changes. It does this by running the pre-required single
state as a test-run by enabling ``test=True``. This test-run will return a
dictionary containing a key named "changes". (See the ``watch`` section above
for examples of "changes" dictionaries.)

If the "changes" key contains a populated dictionary, it means that the
pre-required state expects changes to occur when the state is actually
executed, as opposed to the test-run. The pre-requiring state will now
run. If the pre-requiring state executes successfully, the pre-required
state will then execute. If the pre-requiring state fails, the pre-required
state will not execute.

If the "changes" key contains an empty dictionary, this means that changes are
not expected by the pre-required state. Neither the pre-required state nor the
pre-requiring state will run.

.. _requisites-onfail:

onfail
~~~~~~

.. versionadded:: 2014.7.0

The ``onfail`` requisite allows for reactions to happen strictly as a response
to the failure of another state. This can be used in a number of ways, such as
sending a notification or attempting an alternate task or thread of tasks when
an important state fails.

The ``onfail`` requisite is applied in the same way as ``require`` and ``watch``:

.. code-block:: yaml

    primary_mount:
      mount.mounted:
        - name: /mnt/share
        - device: 10.0.0.45:/share
        - fstype: nfs

    backup_mount:
      mount.mounted:
        - name: /mnt/share
        - device: 192.168.40.34:/share
        - fstype: nfs
        - onfail:
          - mount: primary_mount

.. code-block:: yaml

    build_site:
      cmd.run:
        - name: /srv/web/app/build_site

    notify-build_failure:
      hipchat.send_message:
        - room_id: 123456
        - message: "Building website fail on {{ salt.grains.get('id') }}"


The default behavior of the ``onfail`` when multiple requisites are listed is
the opposite of other requisites in the salt state engine, it acts by default
like ``any()`` instead of ``all()``. This means that when you list multiple
onfail requisites on a state, if *any* fail the requisite will be satisfied.
If you instead need *all* logic to be applied, you can use ``onfail_all``
form:

.. code-block:: yaml

    test_site_a:
      cmd.run:
        - name: ping -c1 10.0.0.1

    test_site_b:
      cmd.run:
        - name: ping -c1 10.0.0.2

    notify_site_down:
      hipchat.send_message:
        - room_id: 123456
        - message: "Both primary and backup sites are down!"
      - onfail_all:
        - cmd: test_site_a
        - cmd: test_site_b

In this contrived example `notify_site_down` will run when both 10.0.0.1 and
10.0.0.2 fail to respond to ping.

.. note::

    Setting failhard (:ref:`globally <global-failhard>` or in
    :ref:`the failing state <state-level-failhard>`) to ``True`` will cause
    ``onfail``, ``onfail_in`` and ``onfail_any`` requisites to be ignored.
    If you want to combine a global failhard set to True with ``onfail``,
    ``onfail_in`` or ``onfail_any``, you will have to explicitly set failhard
    to ``False`` (overriding the global setting) in the state that could fail.

.. note::

    Beginning in the ``2016.11.0`` release of Salt, ``onfail`` uses OR logic for
    multiple listed ``onfail`` requisites. Prior to the ``2016.11.0`` release,
    ``onfail`` used AND logic. See `Issue #22370`_ for more information.
    Beginning in the ``Neon`` release of Salt, a new ``onfail_all`` requisite
    form is available if AND logic is desired.

.. _Issue #22370: https://github.com/saltstack/salt/issues/22370

.. _requisites-use:

use
~~~

The ``use`` requisite is used to inherit the arguments passed in another
id declaration. This is useful when many files need to have the same defaults.

.. code-block:: yaml

    /etc/foo.conf:
      file.managed:
        - source: salt://foo.conf
        - template: jinja
        - mkdirs: True
        - user: apache
        - group: apache
        - mode: 755

    /etc/bar.conf:
      file.managed:
        - source: salt://bar.conf
        - use:
          - file: /etc/foo.conf

The ``use`` statement was developed primarily for the networking states but
can be used on any states in Salt. This makes sense for the networking state
because it can define a long list of options that need to be applied to
multiple network interfaces.

The ``use`` statement does not inherit the requisites arguments of the
targeted state. This means also a chain of ``use`` requisites would not
inherit inherited options.

.. _requisites-in:
.. _requisites-require-in:
.. _requisites-watch-in:
.. _requisites-onchanges-in:

The _in version of requisites
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Direct requisites form a dependency in a single direction. This makes it possible
for Salt to detect cyclical dependencies and helps prevent faulty logic. In some
cases, often in loops, it is desirable to establish a dependency in the opposite
direction.

All direct requisites have an ``_in`` counterpart that behaves the same but forms
the dependency in the opposite direction. The following sls examples will produce
the exact same dependency mapping.

.. code-block:: yaml

    httpd:
      pkg.installed: []
      service.running:
        - require:
          - pkg: httpd

.. code-block:: yaml

    httpd:
      pkg.installed:
        - require_in:
          - service: httpd
      service.running: []

In the following example, Salt will not try to manage the nginx service or any
configuration files unless the nginx package is installed because of the ``pkg:
nginx`` requisite.

.. code-block:: yaml

    nginx:
      pkg.installed: []
      service.running:
        - enable: True
        - reload: True
        - require:
          - pkg: nginx

php.sls

.. code-block:: yaml

    include:
      - http

    php:
      pkg.installed:
        - require_in:
          - service: httpd

mod_python.sls

.. code-block:: yaml

    include:
      - http

    mod_python:
      pkg.installed:
        - require_in:
          - service: httpd

Now the httpd server will only start if both php and mod_python are first verified to
be installed. Thus allowing for a requisite to be defined "after the fact".

.. code-block:: sls

    {% for cfile in salt.pillar.get('nginx:config_files') %}
    /etc/nginx/conf.d/{{ cfile }}:
      file.managed:
        - source: salt://nginx/configs/{{ cfile }}
        - require:
          - pkg: nginx
        - listen_in:
          - service: nginx
    {% endfor %}

In this scenario, ``listen_in`` is a better choice than ``require_in`` because the
``listen`` requisite will trigger ``mod_wait`` behavior which will wait until the
end of state execution and then reload the service.

.. _requisites-any:
.. _requisites-onchanges_any:
.. _requisites-require_any:
.. _requisites-onfail_any:

The _any version of requisites
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

.. versionadded:: 2018.3.0

Some requisites have an ``_any`` counterpart that changes the requisite behavior
from ``all()`` to ``any()``.

.. code-block:: yaml

    A:
      cmd.run:
        - name: echo A
        - require_any:
          - cmd: B
          - cmd: C

    B:
      cmd.run:
        - name: echo B

    C:
      cmd.run:
        - name: /bin/false

In this example `A` will run because at least one of the requirements specified,
`B` or `C`, will succeed.

.. code-block:: yaml

    myservice:
      pkg.installed

    /etc/myservice/myservice.conf:
      file.managed:
        - source: salt://myservice/files/myservice.conf

    /etc/yourservice/yourservice.conf:
      file.managed:
        - source: salt://yourservice/files/yourservice.conf

    /usr/local/sbin/myservice/post-changes-hook.sh
      cmd.run:
        - onchanges_any:
          - file: /etc/myservice/myservice.conf
          - file: /etc/your_service/yourservice.conf
        - require:
          - pkg: myservice

In this example, `cmd.run` would be run only if either of the `file.managed`
states generated changes and at least one of the watched state's "result" is
``True``.

.. _requisites-fire-event:

Altering States
---------------

The state altering system is used to make sure that states are evaluated exactly
as the user expects. It can be used to double check that a state preformed
exactly how it was expected to, or to make 100% sure that a state only runs
under certain conditions. The use of unless or onlyif options help make states
even more stateful. The ``check_cmd`` option helps ensure that the result of a
state is evaluated correctly.

reload
~~~~~~

``reload_modules`` is a boolean option that forces salt to reload its modules
after a state finishes. ``reload_pillar`` and ``reload_grains`` can also be set.
See :ref:`Reloading Modules <reloading-modules>`.

.. code-block:: yaml

    grains_refresh:
      module.run:
       - name: saltutil.refresh_grains
       - reload_grains: true

    grains_read:
      module.run:
       - name: grains.items

.. _unless-requisite:

unless
~~~~~~

.. versionadded:: 2014.7.0

The ``unless`` requisite specifies that a state should only run when any of
the specified commands return ``False``. The ``unless`` requisite operates
as NAND and is useful in giving more granular control over when a state should
execute.

**NOTE**: Under the hood ``unless`` calls ``cmd.retcode`` with
``python_shell=True``. This means the commands referenced by ``unless`` will be
parsed by a shell, so beware of side-effects as this shell will be run with the
same privileges as the salt-minion. Also be aware that the boolean value is
determined by the shell's concept of ``True`` and ``False``, rather than Python's
concept of ``True`` and ``False``.

.. code-block:: yaml

    vim:
      pkg.installed:
        - unless:
          - rpm -q vim-enhanced
          - ls /usr/bin/vim

In the example above, the state will only run if either the vim-enhanced
package is not installed (returns ``False``) or if /usr/bin/vim does not
exist (returns ``False``). The state will run if both commands return
``False``.

However, the state will not run if both commands return ``True``.

Unless checks are resolved for each name to which they are associated.

For example:

.. code-block:: yaml

    deploy_app:
      cmd.run:
        - names:
          - first_deploy_cmd
          - second_deploy_cmd
        - unless: some_check

In the above case, ``some_check`` will be run prior to _each_ name -- once for
``first_deploy_cmd`` and a second time for ``second_deploy_cmd``.

.. versionchanged:: 3000
    The ``unless`` requisite can take a module as a dictionary field in unless.
    The dictionary must contain an argument ``fun`` which is the module that is
    being run, and everything else must be passed in under the args key or will
    be passed as individual kwargs to the module function.

    .. code-block:: yaml

        install apache on debian based distros:
          cmd.run:
            - name: make install
            - cwd: /path/to/dir/whatever-2.1.5/
            - unless:
              - fun: file.file_exists
                path: /usr/local/bin/whatever

    .. code-block:: yaml

      set mysql root password:
        debconf.set:
          - name: mysql-server-5.7
          - data:
              'mysql-server/root_password': {'type': 'password', 'value': {{pillar['mysql.pass']}} }
          - unless:
            - fun: pkg.version
              args:
                - mysql-server-5.7

.. _onlyif-requisite:

onlyif
~~~~~~

.. versionadded:: 2014.7.0

The ``onlyif`` requisite specifies that if each command listed in ``onlyif``
returns ``True``, then the state is run. If any of the specified commands
return ``False``, the state will not run.

**NOTE**: Under the hood ``onlyif`` calls ``cmd.retcode`` with
``python_shell=True``. This means the commands referenced by ``onlyif`` will be
parsed by a shell, so beware of side-effects as this shell will be run with the
same privileges as the salt-minion. Also be aware that the boolean value is
determined by the shell's concept of ``True`` and ``False``, rather than Python's
concept of ``True`` and ``False``.

.. code-block:: yaml

    stop-volume:
      module.run:
        - name: glusterfs.stop_volume
        - m_name: work
        - onlyif:
          - gluster volume status work
        - order: 1

    remove-volume:
      module.run:
        - name: glusterfs.delete
        - m_name: work
        - onlyif:
          - gluster volume info work
        - watch:
          - cmd: stop-volume

The above example ensures that the stop_volume and delete modules only run
if the gluster commands return a 0 ret value.

.. versionchanged:: 3000
    The ``onlyif`` requisite can take a module as a dictionary field in onlyif.
    The dictionary must contain an argument ``fun`` which is the module that is
    being run, and everything else must be passed in under the args key or will
    be passed as individual kwargs to the module function.

    .. code-block:: yaml

        install apache on redhat based distros:
          pkg.latest:
            - name: httpd
            - onlyif:
              - fun: match.grain
                tgt: 'os_family: RedHat'

        install apache on debian based distros:
          pkg.latest:
            - name: apache2
            - onlyif:
              - fun: match.grain
                tgt: 'os_family: Debian'

    .. code-block:: yaml

      arbitrary file example:
        file.touch:
          - name: /path/to/file
          - onlyif:
            - fun: file.search
              args:
                - /etc/crontab
                - 'entry1'

.. _creates-requisite:

Creates
-------

.. versionadded:: 3001

The ``creates`` requisite specifies that a state should only run when any of
the specified files do not already exist. Like ``unless``, ``creates`` requisite
operates as NAND and is useful in giving more granular control over when a state
should execute. This was previously used by the :mod:`cmd <salt.states.cmd>` and
:mod:`docker_container <salt.states.docker_container>` states.

    .. code-block:: yaml

      contrived creates example:
        file.touch:
          - name: /path/to/file
          - creates: /path/to/file

``creates`` also accepts a list of files, in which case this state will
run if **any** of the files do not exist:

    .. code-block:: yaml

      creates list:
        file.cmd:
          - name: /path/to/command
          - creates:
              - /path/file
              - /path/file2

listen
~~~~~~

.. versionadded:: 2017.7.0

The ``runas`` global option is used to set the user which will be used to run
the command in the ``cmd.run`` module.

.. code-block:: yaml

    django:
      pip.installed:
        - name: django >= 1.6, <= 1.7
        - runas: daniel
        - require:
          - pkg: python-pip

In the above state, the pip command run by ``cmd.run`` will be run by the daniel user.

runas_password
~~~~~~~~~~~~~~

.. versionadded:: 2017.7.2

The ``runas_password`` global option is used to set the password used by the
runas global option. This is required by ``cmd.run`` on Windows when ``runas``
is specified. It will be set when ``runas_password`` is defined in the state.

.. code-block:: yaml

    run_script:
      cmd.run:
        - name: Powershell -NonInteractive -ExecutionPolicy Bypass -File C:\\Temp\\script.ps1
        - runas: frank
        - runas_password: supersecret

In the above state, the Powershell script run by ``cmd.run`` will be run by the
frank user with the password ``supersecret``.

check_cmd
~~~~~~~~~

.. versionadded:: 2014.7.0

Check Command is used for determining that a state did or did not run as
expected.

**NOTE**: Under the hood ``check_cmd`` calls ``cmd.retcode`` with
``python_shell=True``. This means the commands referenced by unless will be
parsed by a shell, so beware of side-effects as this shell will be run with the
same privileges as the salt-minion.

.. code-block:: yaml

    comment-repo:
      file.replace:
        - name: /etc/yum.repos.d/fedora.repo
        - pattern: '^enabled=0'
        - repl: enabled=1
        - check_cmd:
          - "! grep 'enabled=0' /etc/yum.repos.d/fedora.repo"

This will attempt to do a replace on all ``enabled=0`` in the .repo file, and
replace them with ``enabled=1``. The ``check_cmd`` is just a bash command. It
will do a grep for ``enabled=0`` in the file, and if it finds any, it will
return a 0, which will be inverted by the leading ``!``, causing ``check_cmd``
to set the state as failed. If it returns a 1, meaning it didn't find any
``enabled=0``, it will be inverted by the leading ``!``, returning a 0, and
declaring the function succeeded.

**NOTE**: This requisite ``check_cmd`` functions differently than the ``check_cmd``
of the ``file.managed`` state.

Overriding Checks
~~~~~~~~~~~~~~~~~

There are two commands used for the above checks.

``mod_run_check`` is used to check for ``onlyif`` and ``unless``. If the goal is to
override the global check for these to variables, include a ``mod_run_check`` in the
salt/states/ file.

``mod_run_check_cmd`` is used to check for the check_cmd options. To override
this one, include a ``mod_run_check_cmd`` in the states file for the state.

Fire Event Notifications
========================

.. versionadded:: 2015.8.0

The `fire_event` option in a state will cause the minion to send an event to
the Salt Master upon completion of that individual state.

The following example will cause the minion to send an event to the Salt Master
with a tag of `salt/state_result/20150505121517276431/dasalt/nano` and the
result of the state will be the data field of the event. Notice that the `name`
of the state gets added to the tag.

.. code-block:: yaml

    nano_stuff:
      pkg.installed:
        - name: nano
        - fire_event: True

In the following example instead of setting `fire_event` to `True`,
`fire_event` is set to an arbitrary string, which will cause the event to be
sent with this tag:
`salt/state_result/20150505121725642845/dasalt/custom/tag/nano/finished`

.. code-block:: yaml

    nano_stuff:
      pkg.installed:
        - name: nano
        - fire_event: custom/tag/nano/finished

Retrying States
===============

.. versionadded:: 2017.7.0

The retry option in a state allows it to be executed multiple times until a desired
result is obtained or the maximum number of attempts have been made.

The retry option can be configured by the ``attempts``, ``until``, ``interval``, and
``splay`` parameters.

The ``attempts`` parameter controls the maximum number of times the state will be
run.  If not specified or if an invalid value is specified, ``attempts`` will default
to ``2``.

The ``until`` parameter defines the result that is required to stop retrying the state.
If not specified or if an invalid value is specified, ``until`` will default to ``True``

The ``interval`` parameter defines the amount of time, in seconds, that the system
will wait between attempts.  If not specified or if an invalid value is specified,
``interval`` will default to ``30``.

The ``splay`` parameter allows the ``interval`` to be additionally spread out.  If not
specified or if an invalid value is specified, ``splay`` defaults to ``0`` (i.e. no
splaying will occur).

The following example will run the pkg.installed state until it returns ``True`` or it has
been run ``5`` times.  Each attempt will be ``60`` seconds apart and the interval will be splayed
up to an additional ``10`` seconds:

.. code-block:: yaml

    my_retried_state:
      pkg.installed:
        - name: nano
        - retry:
            attempts: 5
            until: True
            interval: 60
            splay: 10

The following example will run the pkg.installed state with all the defaults for ``retry``.
The state will run up to ``2`` times, each attempt being ``30`` seconds apart, or until it
returns ``True``.

.. code-block:: yaml

    install_nano:
      pkg.installed:
        - name: nano
        - retry: True

The following example will run the file.exists state every ``30`` seconds up to ``15`` times
or until the file exists (i.e. the state returns ``True``).

.. code-block:: yaml

    wait_for_file:
      file.exists:
        - name: /path/to/file
        - retry:
            attempts: 15
            interval: 30

Return data from a retried state
--------------------------------

When a state is retried, the returned output is as follows:

The ``result`` return value is the ``result`` from the final run.  For example, imagine a state set
to ``retry`` up to three times or ``until`` ``True``.  If the state returns ``False`` on the first run
and then ``True`` on the second, the ``result`` of the state will be ``True``.

The ``started`` return value is the ``started`` from the first run.

The ``duration`` return value is the total duration of all attempts plus the retry intervals.

The ``comment`` return value will include the result and comment from all previous attempts.

For example:

.. code-block:: yaml

    wait_for_file:
      file.exists:
        - name: /path/to/file
        - retry:
            attempts: 10
            interval: 2
            splay: 5

Would return similar to the following.  The state result in this case is ``False`` (file.exist was run 10
times with a 2 second interval, but the file specified did not exist on any run).

.. code-block:: none

          ID: wait_for_file
    Function: file.exists
      Result: False
     Comment: Attempt 1: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 2: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 3: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 4: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 5: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 6: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 7: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 8: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Attempt 9: Returned a result of "False", with the following comment: "Specified path /path/to/file does not exist"
              Specified path /path/to/file does not exist
     Started: 09:08:12.903000
    Duration: 47000.0 ms
     Changes:
