# Highstate data structure definitions

## The Salt State Tree

A state tree is a collection of `SLS` files and directories that live under the directory specified in `file_roots`.

Note

Directory names or filenames in the state tree cannot contain a period, with the exception of the period in the .sls file suffix.

### Top file

The main state file that instructs minions what environment and modules to use during state execution.

Configurable via `state_top`.

See also

A detailed description of the top file

### Include declaration

Defines a list of Module reference strings to include in this `SLS`.

Occurs only in the top level of the SLS data structure.

Example:

    include:
      - edit.vim
      - http.server

### Module reference

The name of a SLS module defined by a separate SLS file and residing on the Salt Master. A module named `edit.vim` is a reference to the SLS file `salt://edit/vim.sls`.

### ID declaration

Defines an individual highstate component. Always references a value of a dictionary containing keys referencing State declaration and Requisite declaration. Can be overridden by a Name declaration or a Names declaration.

Occurs on the top level or under the Extend declaration.

Must be unique across entire state tree. If the same ID declaration is used twice, only the first one matched will be used. All subsequent ID declarations with the same name will be ignored.

Note

Naming gotchas

In Salt versions earlier than 0.9.7, ID declarations containing dots would result in unpredictable output.

### Extend declaration

Extends a Name declaration from an included `SLS module`. The keys of the extend declaration always refer to an existing ID declaration which have been defined in included `SLS modules`.

Occurs only in the top level and defines a dictionary.

States cannot be extended more than once in a single state run.

Extend declarations are useful for adding-to or overriding parts of a State declaration that is defined in another `SLS` file. In the following contrived example, the shown `mywebsite.sls` file is `include` -ing and `extend` -ing the `apache.sls` module in order to add a `watch` declaration that will restart Apache whenever the Apache configuration file, `mywebsite` changes.

    include:
      - apache

    extend:
      apache:
        service:
          - watch:
            - file: mywebsite

    mywebsite:
      file.managed:
        - name: /var/www/mysite

See also

watch_in and require_in

Sometimes it is more convenient to use the watch_in or require_in syntax instead of extending another `SLS` file.

State Requisites

### State declaration

A list which contains one string defining the Function declaration and any number of Function arg declaration dictionaries.

Can, optionally, contain a number of additional components like the name override components — name and names. Can also contain requisite declarations.

Occurs under an ID declaration.

### Requisite declaration

A list containing requisite references.

Used to build the action dependency tree. While Salt states are made to execute in a deterministic order, this order is managed by requiring and watching other Salt states.

Occurs as a list component under a State declaration or as a key under an ID declaration.

### Requisite reference

A single key dictionary. The key is the name of the referenced State declaration and the value is the ID of the referenced ID declaration.

Occurs as a single index in a Requisite declaration list.

### Function declaration

The name of the function to call within the state. A state declaration can contain only a single function declaration.

For example, the following state declaration calls the `installed` function in the `pkg` state module:

    httpd:
      pkg.installed: []

The function can be declared inline with the state as a shortcut. The actual data structure is compiled to this form:

    httpd:
      pkg:
        - installed

Where the function is a string in the body of the state declaration. Technically when the function is declared in dot notation the compiler converts it to be a string in the state declaration list. Note that the use of the first example more than once in an ID declaration is invalid yaml.

INVALID:

    httpd:
      pkg.installed
      service.running

When passing a function without arguments and another state declaration within a single ID declaration, then the long or "standard" format needs to be used since otherwise it does not represent a valid data structure.

VALID:

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

Occurs as the only index in the State declaration list.

### Function arg declaration

A single key dictionary referencing a Python type which is to be passed to the named Function declaration as a parameter. The type must be the data type expected by the function.

Occurs under a Function declaration.

For example in the following state declaration `user`, `group`, and `mode` are passed as arguments to the `managed` function in the `file` state module:

    /etc/http/conf/http.conf:
      file.managed:
        - user: root
        - group: root
        - mode: 644

### Name declaration

Overrides the `name` argument of a State declaration. If `name` is not specified the ID declaration satisfies the `name` argument.

The name is always a single key dictionary referencing a string.

Overriding `name` is useful for a variety of scenarios.

For example, avoiding clashing ID declarations. The following two state declarations cannot both have `/etc/motd` as the ID declaration:

    motd_perms:
      file.managed:
        - name: /etc/motd
        - mode: 644

    motd_quote:
      file.append:
        - name: /etc/motd
        - text: "Of all smells, bread; of all tastes, salt."

Another common reason to override `name` is if the ID declaration is long and needs to be referenced in multiple places. In the example below it is much easier to specify `mywebsite` than to specify `/etc/apache2/sites-available/mywebsite.com` multiple times:

    mywebsite:
      file.managed:
        - name: /etc/apache2/sites-available/mywebsite.com
        - source: salt://mywebsite.com

    a2ensite mywebsite.com:
      cmd.wait:
        - unless: test -L /etc/apache2/sites-enabled/mywebsite.com
        - watch:
          - file: mywebsite

    apache2:
      service.running:
        - watch:
          - file: mywebsite

### Names declaration

Expands the contents of the containing State declaration into multiple state declarations, each with its own name.

For example, given the following state declaration:

    python-pkgs:
      pkg.installed:
        - names:
          - python-django
          - python-crypto
          - python-yaml

Once converted into the lowstate data structure the above state declaration will be expanded into the following three state declarations:

    python-django:
      pkg.installed

    python-crypto:
      pkg.installed

    python-yaml:
      pkg.installed

Other values can be overridden during the expansion by providing an additional dictionary level.

Added in version 2014.7.0.

    ius:
      pkgrepo.managed:
        - humanname: IUS Community Packages for Enterprise Linux 6 - $basearch
        - gpgcheck: 1
        - baseurl: http://mirror.rackspace.com/ius/stable/CentOS/6/$basearch
        - gpgkey: http://dl.iuscommunity.org/pub/ius/IUS-COMMUNITY-GPG-KEY
        - names:
            - ius
            - ius-devel:
                - baseurl: http://mirror.rackspace.com/ius/development/CentOS/6/$basearch

## Large example

Here is the layout in yaml using the names of the highdata structure components.

    <Include Declaration>:
      - <Module Reference>
      - <Module Reference>

    <Extend Declaration>:
      <ID Declaration>:
        [<overrides>]

    # standard declaration

    <ID Declaration>:
      <State Module>:
        - <Function>
        - <Function Arg>
        - <Function Arg>
        - <Function Arg>
        - <Name>: <name>
        - <Requisite Declaration>:
          - <Requisite Reference>
          - <Requisite Reference>

    # inline function and names

    <ID Declaration>:
      <State Module>.<Function>:
        - <Function Arg>
        - <Function Arg>
        - <Function Arg>
        - <Names>:
          - <name>
          - <name>
          - <name>
        - <Requisite Declaration>:
          - <Requisite Reference>
          - <Requisite Reference>

    # multiple states for single id

    <ID Declaration>:
      <State Module>:
        - <Function>
        - <Function Arg>
        - <Name>: <name>
        - <Requisite Declaration>:
          - <Requisite Reference>
      <State Module>:
        - <Function>
        - <Function Arg>
        - <Names>:
          - <name>
          - <name>
        - <Requisite Declaration>:
          - <Requisite Reference>