Added ext_pillar Django model field access through the ORM

This external pillar will load django model fields into pillar
data.

doc/ref/pillar/all/index.rst

@@ -13,6 +13,7 @@ Full list of builtin pillar modules
     cmd_json
     cmd_yaml
     cobbler
+    django_orm
     git_pillar
     hiera
     libvirt

doc/ref/pillar/all/salt.pillar.django_orm.rst

@@ -0,0 +1,6 @@
+======================
+salt.pillar.django_orm
+======================
+
+.. automodule:: salt.pillar.django_orm
+    :members:

salt/pillar/django_orm.py

@@ -0,0 +1,186 @@
+# -*- coding: utf-8 -*-
+'''
+Generate pillar data from Django models through the Django ORM
+
+:maintainer: Micah Hausler <micah.hausler@gmail.com>
+:maturity: new
+
+
+Configuring the django_orm ext_pillar
+================================
+
+To use this module, your Django project must be on the saltmaster server with
+databse access. This assumes you are using virtualenv with all the project's
+requirements installed.
+
+.. code-block:: yaml
+
+    ext_pillar:
+      - django_orm:
+        pillar_name: my_application
+        env: /path/to/virtualenv/
+        project_path: /path/to/project/
+        env_file: /path/to/env/file.sh
+        settings_module: my_application.settings
+
+        django_app:
+
+          # Required: the app that is included in INSTALLED_APPS
+          my_application.clients:
+
+            # Required: the model name
+            Client:
+
+              # Required: model field to use as a name in the
+              # rendered pillar, should be unique
+              name: shortname
+
+              # Optional:
+              # See the Django QuerySet docuemntation for how to use .filter()
+              filter:  {'kw': 'args'}
+
+              # Required: a list of field names
+              fields:
+                - field_1
+                - field_2
+
+
+This would return pillar data that would look like
+
+.. code-block:: yaml
+
+    my_application:
+      my_application.clients:
+        Client:
+          client_1:
+            field_1: data_from_field_1
+            field_2: data_from_field_2
+          client_2:
+            field_1: data_from_field_1
+            field_2: data_from_field_2
+
+
+Module Documentation
+====================
+'''
+
+import logging
+import os
+import sys
+
+
+HAS_VIRTUALENV = False
+
+try:
+    import virtualenv
+    HAS_VIRTUALENV = True
+except ImportError:
+    pass
+
+log = logging.getLogger(__name__)
+
+
+def __virtual__():
+    if not HAS_VIRTUALENV:
+        log.warn('virtualenv not installed, please install first')
+        return False
+    return 'django_orm'
+
+
+def ext_pillar(minion_id,
+               pillar,
+               pillar_name,
+               env,
+               project_path,
+               settings_module,
+               django_app,
+               env_file=None,
+               *args,
+               **kwargs):
+    '''
+    Connect to a django database through the ORM and retrieve model fields
+
+    Parameters:
+        * `pillar_name`: The name of the pillar to be returned
+        * `env`: The full path to the virtualenv for your django project
+        * `project_path`: The full path to your django project (the directory
+          manage.py is in.)
+        * `settings_module`: The settings module for your project. This can be
+          found in your manage.py file.
+        * `django_app`: A dictionary containing your apps, models, and fields
+        * `env_file`: A bash file that sets up your environment. The file is
+          run in a subprocess and the changed variables are then added.
+    '''
+
+    if not os.path.isdir(project_path):
+        log.error('Django project dir: \'{}\' not a directory!'.format(env))
+        return {}
+    for path in virtualenv.path_locations(env):
+        if not os.path.isdir(path):
+            log.error('Virtualenv {} not a directory!'.format(path))
+            return {}
+
+    # load the virtualenv
+    sys.path.append(virtualenv.path_locations(env)[1] + '/site-packages/')
+    # load the django project
+    sys.path.append(project_path)
+
+    os.environ['DJANGO_SETTINGS_MODULE'] = settings_module
+
+    if env_file is not None:
+        import subprocess
+
+        base_env = {}
+        proc = subprocess.Popen(['bash', '-c', 'env'], stdout=subprocess.PIPE)
+        for line in proc.stdout:
+            (key, _, value) = line.partition('=')
+            base_env[key] = value
+
+        command = ['bash', '-c', 'source {0} && env'.format(env_file)]
+        proc = subprocess.Popen(command, stdout=subprocess.PIPE)
+
+        for line in proc.stdout:
+            (key, _, value) = line.partition('=')
+            # only add a key if it is different or doesn't already exist
+            if key not in base_env or base_env[key] != value:
+                os.environ[key] = value.rstrip('\n')
+                log.debug('Adding {} = {} to django environment'.format(
+                            key,
+                            value.rstrip('\n')))
+
+    try:
+        import importlib
+
+        django_pillar = {}
+
+        for app, models in django_app.iteritems():
+            django_pillar[app] = {}
+            model_file = importlib.import_module(app + '.models')
+            for model_name, model_meta in models.iteritems():
+                model_orm = model_file.__dict__[model_name]
+                django_pillar[app][model_orm.__name__] = {}
+
+                fields = model_meta['fields']
+
+                if 'filter' in model_meta.keys():
+                    qs = model_orm.objects.filter(**model_meta['filter'])
+                else:
+                    qs = model_orm.objects.all()
+
+                # Loop through records for the queryset
+                for model in qs:
+                    django_pillar[app][model_orm.__name__][
+                            model.__dict__[
+                                model_meta['name']
+                            ]] = {}
+
+                    for field in fields:
+                        django_pillar[app][model_orm.__name__][
+                                        model.__dict__[
+                                            model_meta['name']
+                                        ]][field] = model.__dict__[field]
+
+        return {pillar_name: django_pillar}
+    except ImportError, e:
+        log.error('Failed to import library: {}'.format(e.message))
+        return {}