r"""
Saltclass Configuration
=======================

.. code-block:: yaml

    master_tops:
      saltclass:
        path: /srv/saltclass

Description
===========

This module clones the behaviour of reclass (http://reclass.pantsfullofunix.net/),
without the need of an external app, and add several features to improve flexibility.
Saltclass lets you define your nodes from simple ``yaml`` files (``.yml``) through
hierarchical class inheritance with the possibility to override pillars down the tree.

Features
========

- Define your nodes through hierarchical class inheritance
- Reuse your reclass datas with minimal modifications
    - applications => states
    - parameters => pillars
- Use Jinja templating in your yaml definitions
- Access to the following Salt objects in Jinja
    - ``__opts__``
    - ``__salt__``
    - ``__grains__``
    - ``__pillars__``
    - ``minion_id``
- Chose how to merge or override your lists using ^ character (see examples)
- Expand variables ${} with possibility to escape them if needed \${} (see examples)
- Ignores missing node/class and will simply return empty without breaking the pillar module completely - will be logged

The original example subset hosted at ``git.mauras.ch`` is no longer
reachable; see the ``salt/tops/saltclass`` test fixtures in the Salt
source tree for working examples.

==========================  ===========
Terms usable in yaml files  Description
==========================  ===========
classes                     A list of classes that will be processed in order
states                      A list of states that will be returned by master_tops function
pillars                     A yaml dictionary that will be returned by the ext_pillar function
environment                 Node saltenv that will be used by master_tops
==========================  ===========

A class consists of:

- zero or more parent classes
- zero or more states
- any number of pillars

A child class can override pillars from a parent class.
A node definition is a class in itself with an added ``environment`` parameter for ``saltenv`` definition.

Class names
===========

Class names mimic salt way of defining states and pillar files.
This means that ``default.users`` class name will correspond to one of these:

- ``<saltclass_path>/classes/default/users.yml``
- ``<saltclass_path>/classes/default/users/init.yml``

Saltclass file hierarchy
========================

A saltclass tree would look like this:

.. code-block:: text

    <saltclass_path>
    ├── classes
    │   ├── app
    │   │   ├── borgbackup.yml
    │   │   └── ssh
    │   │       └── server.yml
    │   ├── default
    │   │   ├── init.yml
    │   │   ├── motd.yml
    │   │   └── users.yml
    │   ├── roles
    │   │   ├── app.yml
    │   │   └── nginx
    │   │       ├── init.yml
    │   │       └── server.yml
    │   └── subsidiaries
    │       ├── gnv.yml
    │       ├── qls.yml
    │       └── zrh.yml
    └── nodes
        ├── geneva
        │   └── gnv.node1.yml
        ├── lausanne
        │   ├── qls.node1.yml
        │   └── qls.node2.yml
        ├── node127.yml
        └── zurich
            ├── zrh.node1.yml
            ├── zrh.node2.yml
            └── zrh.node3.yml


Saltclass Examples
==================

``<saltclass_path>/nodes/lausanne/qls.node1.yml``

.. code-block:: jinja

    environment: base

    classes:
    {% for class in ['default'] %}
      - {{ class }}
    {% endfor %}
      - subsidiaries.{{ __grains__['id'].split('.')[0] }}

``<saltclass_path>/classes/default/init.yml``

.. code-block:: yaml

    classes:
      - default.users
      - default.motd

    states:
      - openssh

    pillars:
      default:
        network:
          dns:
            srv1: 192.168.0.1
            srv2: 192.168.0.2
            domain: example.com
        ntp:
          srv1: 192.168.10.10
          srv2: 192.168.10.20

``<saltclass_path>/classes/subsidiaries/gnv.yml``

.. code-block:: yaml

    pillars:
      default:
        network:
          sub: Geneva
          dns:
            srv1: 10.20.0.1
            srv2: 10.20.0.2
            srv3: 192.168.1.1
            domain: gnv.example.com
        users:
          adm1:
            uid: 1210
            gid: 1210
            gecos: 'Super user admin1'
            homedir: /srv/app/adm1
          adm3:
            uid: 1203
            gid: 1203
            gecos: 'Super user adm

Variable expansions
===================

Escaped variables are rendered as is: ``${test}``

Missing variables are rendered as is: ``${net:dns:srv2}``

.. code-block:: yaml

    pillars:
      app:
      config:
        dns:
          srv1: ${default:network:dns:srv1}
          srv2: ${net:dns:srv2}
        uri: https://application.domain/call?\${test}
        prod_parameters:
          - p1
          - p2
          - p3
      pkg:
        - app-core
        - app-backend

List override
=============

Not using ``^`` as the first entry will simply merge the lists

.. code-block:: yaml

    pillars:
      app:
        pkg:
          - ^
          - app-frontend


.. note:: **Known limitation**

    Currently you can't have both a variable and an escaped variable in the same string as the
    escaped one will not be correctly rendered - '\${xx}' will stay as is instead of being rendered as '${xx}'
"""

import logging

import salt.utils.saltclass as sc

log = logging.getLogger(__name__)


def __virtual__():
    """
    Only run if properly configured
    """
    if __opts__["master_tops"].get("saltclass"):
        return True
    return False


def top(**kwargs):
    """
    Compile tops
    """
    # Node definitions path will be retrieved from args (or set to default),
    # then added to 'salt_data' dict that is passed to the 'get_pillars'
    # function. The dictionary contains:
    #     - __opts__
    #     - __salt__
    #     - __grains__
    #     - __pillar__
    #     - minion_id
    #     - path
    #
    # If successful, the function will return a pillar dict for minion_id.

    # If path has not been set, make a default
    _opts = __opts__["master_tops"]["saltclass"]
    if "path" not in _opts:
        path = "/srv/saltclass"
        log.warning("path variable unset, using default: %s", path)
    else:
        path = _opts["path"]

    # Create a dict that will contain our salt objects
    # to send to get_tops function
    if "id" not in kwargs["opts"]:
        log.warning("Minion id not found - Returning empty dict")
        return {}
    else:
        minion_id = kwargs["opts"]["id"]

    salt_data = {
        "__opts__": kwargs["opts"],
        "__salt__": {},
        "__grains__": kwargs["grains"],
        "__pillar__": {},
        "minion_id": minion_id,
        "path": path,
    }

    return sc.get_tops(minion_id, salt_data)
